main.go

package main

import (
	"crypto/tls"
	"encoding/csv"
	"encoding/json"
	"errors"
	"fmt"
	"html"
	"html/template"
	"io"
	"log"
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"reflect"
	"strconv"
	"strings"
	"time"

	gz "github.com/NYTimes/gziphandler"
	"github.com/bradfitz/gomemcache/memcache"
	gsm "github.com/bradleypeabody/gorilla-sessions-memcache"
	sqlite "github.com/gwenn/gosqlite"
	"github.com/segmentio/ksuid"
	com "github.com/sqlitebrowser/dbhub.io/common"
	gfm "github.com/sqlitebrowser/github_flavored_markdown"
	"golang.org/x/oauth2"
)

var (
	// Log file for incoming HTTPS requests
	reqLog *os.File

	// Our parsed HTML templates
	tmpl *template.Template

	// Session cookie storage
	store *gsm.MemcacheStore
)

// apiKeyGenHandler generates a new API key, stores it in the PG database, and returns the details to the caller
func apiKeyGenHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Generate new API key
	creationTime := time.Now()
	keyRaw, err := ksuid.NewRandom()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	key := keyRaw.String()

	// Save the API key in PG database
	err = com.APIKeySave(key, loggedInUser, creationTime)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Log the key creation
	log.Printf("New API key created for user '%s', key: '%s'\n", loggedInUser, key)

	// Return the API key to the caller
	d := com.APIKey{
		Key:         key,
		DateCreated: creationTime,
	}
	data, err := json.Marshal(d)
	if err != nil {
		log.Println(err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	fmt.Fprint(w, string(data))
}

// auth0CallbackHandler is called at the end of the Auth0 authentication process, whether successful or not.
// If the authentication process was successful:
//   - if the user already has an account on our system then this function creates a login session for them.
//   - if the user doesn't yet have an account on our system, they're bounced to the username selection page.
//
// If the authentication process wasn't successful, an error message is displayed.
func auth0CallbackHandler(w http.ResponseWriter, r *http.Request) {
	// Auth0 login part, mostly copied from https://github.com/auth0-samples/auth0-golang-web-app (MIT License)
	conf := &oauth2.Config{
		ClientID:     com.Conf.Auth0.ClientID,
		ClientSecret: com.Conf.Auth0.ClientSecret,
		RedirectURL:  "https://" + com.Conf.Web.ServerName + "/x/callback",
		Scopes:       []string{"openid", "profile"},
		Endpoint: oauth2.Endpoint{
			AuthURL:  "https://" + com.Conf.Auth0.Domain + "/authorize",
			TokenURL: "https://" + com.Conf.Auth0.Domain + "/oauth/token",
		},
	}
	code := r.URL.Query().Get("code")
	if code == "" {
		log.Printf("Login failure from '%v', probably due to blocked 3rd party cookies\n", r.RemoteAddr)
		errorPage(w, r, http.StatusInternalServerError,
			"Login failure.  Please allow 3rd party cookies from https://dbhub.eu.auth0.com then try again (it should then work).")
		return
	}
	token, err := conf.Exchange(oauth2.NoContext, code)
	if err != nil {
		log.Printf("Login failure: %s\n", err.Error())
		errorPage(w, r, http.StatusInternalServerError, "Login failed")
		return
	}

	// Retrieve the user info (JSON format)
	conn := conf.Client(oauth2.NoContext, token)
	userInfo, err := conn.Get("https://" + com.Conf.Auth0.Domain + "/userinfo")
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	raw, err := io.ReadAll(userInfo.Body)
	defer userInfo.Body.Close()
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Convert the JSON into something usable
	var profile map[string]interface{}
	if err = json.Unmarshal(raw, &profile); err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Extract the basic user info we use
	var auth0Conn, auth0ID, avatarURL, email, nickName string
	em := profile["email"]
	if em != nil {
		email = em.(string)
	}
	au := profile["user_id"]
	if au != nil {
		auth0ID = au.(string)
	}
	if auth0ID == "" {
		log.Printf("Auth0 callback error: Auth0 ID string was empty. Email: %s\n", email)
		errorPage(w, r, http.StatusInternalServerError, "Error: Auth0 ID string was empty")
		return
	}
	ni := profile["nickname"]
	if ni != nil {
		nickName = ni.(string)
	}

	// Determine if the user has a profile pic we can use
	var i map[string]interface{}
	if profile["identities"] != nil {
		i = profile["identities"].([]interface{})[0].(map[string]interface{})
	}
	co, ok := i["connection"]
	if ok {
		auth0Conn = co.(string)
	}
	if auth0Conn != "Test2DB" { // The Auth0 fallback profile pic's seem pretty lousy, so avoid those
		p, ok := profile["picture"]
		if ok && p.(string) != "" {
			avatarURL = p.(string)
		}
	}

	// If the user has an unverified email address, tell them to verify it before proceeding
	ve := profile["email_verified"]
	if ve != nil && ve.(bool) != true {
		// TODO: Create a nicer notice page for this, as errorPage() doesn't look friendly
		errorPage(w, r, http.StatusUnauthorized, "Please check your email.  You need to verify your "+
			"email address before logging in will work.")
		return
	}

	// Determine the DBHub.io username matching the given Auth0 ID
	userName, err := com.UserNameFromAuth0ID(auth0ID)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// If the user doesn't already exist, we need to create an account for them
	if userName == "" {
		if email != "" {
			// Check if the email address is already in our system
			exists, err := com.CheckEmailExists(email)
			if err != nil {
				errorPage(w, r, http.StatusInternalServerError, "Email check failed.  Can't continue.")
				return
			}
			if exists {
				errorPage(w, r, http.StatusConflict,
					"Can't create new account: Your email address is already associated "+
						"with a different account in our system.")
				return
			}
		}

		// Create a special session cookie, purely for the registration page
		sess, err := store.Get(r, "user-reg")
		if err != nil {
			if err == memcache.ErrCacheMiss {
				// Seems like a stale session token, so delete the session and reload the page
				sess.Options.MaxAge = -1
				err = sess.Save(r, w)
				if err != nil {
					errorPage(w, r, http.StatusInternalServerError, err.Error())
					return
				}
				http.Redirect(w, r, "/selectusername", http.StatusTemporaryRedirect)
				return
			}
			errorPage(w, r, http.StatusBadRequest, err.Error())
			return
		}
		sess.Values["registrationinprogress"] = true
		sess.Values["auth0id"] = auth0ID
		sess.Values["avatar"] = avatarURL
		sess.Values["email"] = email
		sess.Values["nickname"] = nickName
		err = sess.Save(r, w)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}

		// Bounce to a new page, for the user to select their preferred username
		http.Redirect(w, r, "/selectusername", http.StatusSeeOther)
		return
	}

	// If Auth0 provided a picture URL for the user, check if it's different to what we already have (eg it may have
	// been updated)
	if avatarURL != "" {
		usr, err := com.User(userName)
		if err != nil {
			errorPage(w, r, http.StatusBadRequest, err.Error())
			return
		}
		if usr.AvatarURL != avatarURL {
			// The Auth0 provided pic URL is different to what we have already, so we update the database with the new
			// value
			err = com.UpdateAvatarURL(userName, avatarURL)
			if err != nil {
				errorPage(w, r, http.StatusBadRequest, err.Error())
				return
			}
		}
	}

	// Create a session cookie for the user
	sess, err := store.Get(r, "dbhub-user")
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, err.Error())
		return
	}
	sess.Values["UserName"] = userName
	sess.Save(r, w)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Login completed, so bounce to the users' profile page
	http.Redirect(w, r, "/"+userName, http.StatusSeeOther)
}

// Returns a list of the branches present in a database
func branchNamesHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, true)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbOwner := strings.ToLower(usr)

	// If any of the required values were empty, indicate failure
	if dbOwner == "" || dbFolder == "" || dbName == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, false)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	if !exists {
		log.Printf("%s: Validation failed for database name: %s", com.GetCurrentFunctionName(), err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Retrieve the branch info for the database
	branchList, err := com.GetBranches(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	defBranch, err := com.GetDefaultBranchName(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}

	// Prepare the branch list for sending
	var b struct {
		Branches      []string `json:"branches"`
		DefaultBranch string   `json:"default_branch"`
	}
	for name := range branchList {
		b.Branches = append(b.Branches, name)
	}
	b.DefaultBranch = defBranch
	data, err := json.MarshalIndent(b, "", " ")
	if err != nil {
		log.Println(err)
		return
	}

	// Return the branch list
	w.WriteHeader(http.StatusOK)
	fmt.Fprint(w, string(data))
}

func checkLogin(r *http.Request) (loggedInUser string, validSession bool, err error) {
	// Retrieve session data (if any)
	var u interface{}
	if com.Conf.Environment.Environment == "production" {
		sess, err := store.Get(r, "dbhub-user")
		if err != nil {
			return "", false, err
		}
		u = sess.Values["UserName"]
	} else {
		// Non-production environments (eg dev, test) can directly set the logged in user
		u = com.Conf.Environment.UserOverride
		if u == "" {
			u = nil
		}
	}
	if u != nil {
		loggedInUser = u.(string)
		validSession = true
	}

	return
}

func collectPageAuth0Info() (auth0 com.Auth0Set) {
	auth0.CallbackURL = "https://" + com.Conf.Web.ServerName + "/x/callback"
	auth0.ClientID = com.Conf.Auth0.ClientID
	auth0.Domain = com.Conf.Auth0.Domain
	return
}

func collectPageMetaInfo(r *http.Request, meta *com.MetaInfo, requireLogin bool, getOwnerAndDatabaseFromUrl bool, getOwnerAndDatabaseFromData bool) (errCode int, err error) {
	// Server name
	meta.Server = com.Conf.Web.ServerName

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		return http.StatusBadRequest, err
	}
	if validSession {
		meta.LoggedInUser = loggedInUser
	}

	// Ensure we have a valid logged in user
	if requireLogin && !validSession {
		return http.StatusUnauthorized, fmt.Errorf("You need to be logged in")
	}

	// Retrieve the details and status updates count for the logged in user
	if validSession {
		ur, err := com.User(loggedInUser)
		if err != nil {
			return http.StatusBadRequest, err
		}
		if ur.AvatarURL != "" {
			meta.AvatarURL = ur.AvatarURL + "&s=48"
		}
		meta.NumStatusUpdates, err = com.UserStatusUpdates(loggedInUser)
		if err != nil {
			return http.StatusBadRequest, err
		}
	}

	// Retrieve the database owner & name
	if getOwnerAndDatabaseFromUrl || getOwnerAndDatabaseFromData {
		// TODO: Add folder and branch name support
		var dbOwner, dbName string
		if getOwnerAndDatabaseFromUrl {
			dbOwner, dbName, err = com.GetOD(1, r) // 1 = Ignore "/xxx/" at the start of the URL
			if err != nil {
				return http.StatusBadRequest, err
			}
		} else {
			// Get owner + dbname combination from post data
			dbOwner, _, dbName, err = com.GetUFD(r, true)
			if dbOwner == "" || dbName == "" {
				err = nil
				return
			}
			if err != nil {
				return http.StatusBadRequest, err
			}
		}

		// Validate the supplied information
		if dbOwner == "" || dbName == "" {
			return http.StatusBadRequest, fmt.Errorf("Missing database owner or database name")
		}

		// Check if the database exists
		exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, "/", dbName, false)
		if err != nil {
			return http.StatusInternalServerError, fmt.Errorf("Database failure when looking up database details")
		}
		if !exists {
			return http.StatusNotFound, fmt.Errorf("That database doesn't seem to exist")
		}

		// Retrieve correctly capitalised username for the database owner
		usr, err := com.User(dbOwner)
		if err != nil {
			return http.StatusBadRequest, err
		}

		// Store information
		meta.Database = dbName
		meta.Owner = usr.Username
		meta.Folder = "/"

		// Retrieve the "forked from" information
		meta.ForkOwner, meta.ForkFolder, meta.ForkDatabase, meta.ForkDeleted, err = com.ForkedFrom(meta.Owner, meta.Folder, meta.Database)
		if err != nil {
			return http.StatusBadRequest, err
		}
	}

	// Pass along the environment setting
	meta.Environment = com.Conf.Environment.Environment

	return
}

func createBranchHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		errorPage(w, r, http.StatusUnauthorized, "You need to be logged in")
		return
	}

	// Extract and validate the form variables
	dbOwner, dbName, commit, err := com.GetFormUDC(r)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Missing or incorrect data supplied")
		return
	}
	branchName, err := com.GetFormBranch(r)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Missing or incorrect branch name")
		return
	}
	bd := r.PostFormValue("branchdesc") // Optional

	// If given, validate the branch description field
	var branchDesc string
	if bd != "" {
		err = com.Validate.Var(bd, "markdownsource")
		if err != nil {
			errorPage(w, r, http.StatusBadRequest, "Invalid characters in branch description")
			return
		}
		branchDesc = bd
	}

	// Check if the requested database exists
	dbFolder := "/"
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	if !exists {
		errorPage(w, r, http.StatusNotFound, fmt.Sprintf("Database '%s%s%s' doesn't exist", dbOwner, dbFolder,
			dbName))
		return
	}

	// Read the branch heads list from the database
	branches, err := com.GetBranches(dbOwner, dbFolder, dbName)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Make sure the branch name doesn't already exist
	_, ok := branches[branchName]
	if ok {
		errorPage(w, r, http.StatusConflict, "A branch of that name already exists!")
		return
	}

	// Count the number of commits in the new branch
	commitList, err := com.GetCommitList(dbOwner, dbFolder, dbName)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	c, ok := commitList[commit]
	if !ok {
		errorPage(w, r, http.StatusBadRequest, fmt.Sprint("The given commit ID doesn't exist"))
		return
	}
	commitCount := 1
	for c.Parent != "" {
		commitCount++
		c, ok = commitList[c.Parent]
		if !ok {
			log.Printf("Error when counting commits in new branch '%s' of database '%s%s%s'\n", com.SanitiseLogString(branchName),
				com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName))
			return
		}
	}

	// Create the branch
	newBranch := com.BranchEntry{
		Commit:      commit,
		CommitCount: commitCount,
		Description: branchDesc,
	}
	branches[branchName] = newBranch
	err = com.StoreBranches(dbOwner, dbFolder, dbName, branches)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Invalidate the memcache data for the database, so the new branch count gets picked up
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Bounce to the branches page
	http.Redirect(w, r, fmt.Sprintf("/branches/%s%s%s", loggedInUser, dbFolder, dbName), http.StatusSeeOther)
}

// Receives incoming info for adding a comment to an existing discussion
func createCommentHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		fmt.Fprint(w, "You need to be logged in")
		return
	}

	// Extract and validate the form variables
	dbOwner, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Missing or incorrect data supplied")
		return
	}

	// Ensure a discussion ID was given
	a := r.PostFormValue("discid")
	if a == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Missing discussion id")
		return
	}
	discID, err := strconv.Atoi(a)
	if err != nil {
		log.Printf("Error converting string '%s' to integer in function '%s': %s\n", com.SanitiseLogString(a),
			com.GetCurrentFunctionName(), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Error when parsing discussion id value")
		return
	}

	// Check if the discussion should also be closed or reopened
	discClose := false
	c := r.PostFormValue("close")
	if c == "true" {
		discClose = true
	}

	// If comment text was provided, then validate it.  Note that if the flag for closing/reopening the discussion has
	// been set, then comment text isn't required.  In all other situations it is
	rawTxt := r.PostFormValue("comtext")
	if rawTxt == "" && discClose == false {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Comment can't be empty!")
		return
	}
	var comText string
	if discClose == false || (discClose == true && rawTxt != "") {
		// Unescape and validate the comment text
		t, err := url.QueryUnescape(rawTxt)
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			fmt.Fprint(w, "Error when unescaping comment field value")
			return
		}
		err = com.Validate.Var(t, "markdownsource")
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			fmt.Fprint(w, "Invalid characters in the new discussions' main text field")
			return
		}
		comText = t
	}

	// Check if the requested database exists
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, false) // We don't require write access since discussions are considered public
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	if !exists {
		w.WriteHeader(http.StatusNotFound)
		fmt.Fprintf(w, "Database '%s%s%s' doesn't exist", dbOwner, dbFolder, dbName)
		return
	}

	// Add the comment to PostgreSQL
	err = com.StoreComment(dbOwner, dbFolder, dbName, loggedInUser, discID, comText, discClose,
		com.CLOSED_WITHOUT_MERGE) // com.CLOSED_WITHOUT_MERGE is ignored for discussions.  It's only used for MRs
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}

	// Invalidate the memcache data for the database, so if the discussion counter for the database was changed it
	// gets picked up
	if discClose {
		err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
		if err != nil {
			// Something went wrong when invalidating memcached entries for the database
			log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
			return
		}
	}

	// Send a success message
	w.WriteHeader(http.StatusOK)
}

// Receives incoming info from the "Create a new discussion" page, adds the discussion to PostgreSQL,
// then bounces to the discussion page
func createDiscussHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		errorPage(w, r, http.StatusUnauthorized, "You need to be logged in")
		return
	}

	// Extract and validate the form variables
	dbOwner, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Missing or incorrect data supplied")
		return
	}

	// Validate the discussions' title
	tl := r.PostFormValue("title")
	err = com.ValidateDiscussionTitle(tl)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Invalid characters in the new discussions' title")
		return
	}
	discTitle := tl

	// Validate the discussions' text
	txt := r.PostFormValue("disctxt")
	if txt == "" {
		errorPage(w, r, http.StatusBadRequest, "Discussion body can't be empty!")
		return
	}
	err = com.Validate.Var(txt, "markdownsource")
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Invalid characters in the new discussions' main text field")
		return
	}
	discText := txt

	// Check if the requested database exists
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, false) // We don't require write access since discussions are considered public
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	if !exists {
		errorPage(w, r, http.StatusNotFound, fmt.Sprintf("Database '%s%s%s' doesn't exist", dbOwner, dbFolder,
			dbName))
		return
	}

	// Add the discussion detail to PostgreSQL
	id, err := com.StoreDiscussion(dbOwner, dbFolder, dbName, loggedInUser, discTitle, discText, com.DISCUSSION,
		com.MergeRequestEntry{})
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Generate an event about the new discussion
	details := com.EventDetails{
		DBName:   dbName,
		DiscID:   id,
		Folder:   dbFolder,
		Owner:    dbOwner,
		Title:    discTitle,
		Type:     com.EVENT_NEW_DISCUSSION,
		URL:      fmt.Sprintf("/discuss/%s%s%s?id=%d", url.PathEscape(dbOwner), dbFolder, url.PathEscape(dbName), id),
		UserName: loggedInUser,
	}
	err = com.NewEvent(details)
	if err != nil {
		log.Printf("Error when creating a new event: %s\n", err.Error())
		return
	}

	// Invalidate the memcache data for the database, so the new discussion count gets picked up
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Bounce to the discussions page
	http.Redirect(w, r, fmt.Sprintf("/discuss/%s%s%s?id=%d", dbOwner, dbFolder, dbName, id), http.StatusSeeOther)
}

// Receives incoming requests from the merge request creation page, creating them if the info is correct
func createMergeHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		fmt.Fprint(w, "You need to be logged in")
		return
	}

	// Extract and validate the form variables
	userName, err := com.GetUsername(r, false)
	if err != nil {
		w.WriteHeader(http.StatusUnauthorized)
		fmt.Fprint(w, err.Error())
		return
	}
	if userName == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Missing username in supplied fields")
		return
	}

	// Retrieve source owner
	o := r.PostFormValue("sourceowner")
	srcOwner, err := url.QueryUnescape(o)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateUser(srcOwner)
	if err != nil {
		log.Printf("Validation failed for username: '%s'- %s", com.SanitiseLogString(srcOwner), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve source folder
	f := r.PostFormValue("sourcefolder")
	srcFolder, err := url.QueryUnescape(f)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateFolder(srcFolder)
	if err != nil {
		log.Printf("Validation failed for folder: '%s' - %s", com.SanitiseLogString(srcFolder), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve source database name
	d := r.PostFormValue("sourcedbname")
	srcDBName, err := url.QueryUnescape(d)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateDB(srcDBName)
	if err != nil {
		log.Printf("Validation failed for database name '%s': %s", com.SanitiseLogString(srcDBName), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve source branch name
	a := r.PostFormValue("sourcebranch")
	srcBranch, err := url.QueryUnescape(a)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateBranchName(srcBranch)
	if err != nil {
		log.Printf("Validation failed for branch name '%s': %s", com.SanitiseLogString(srcBranch), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve destination owner
	o = r.PostFormValue("destowner")
	destOwner, err := url.QueryUnescape(o)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateUser(destOwner)
	if err != nil {
		log.Printf("Validation failed for username: '%s'- %s", com.SanitiseLogString(destOwner), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve destination folder
	f = r.PostFormValue("destfolder")
	destFolder, err := url.QueryUnescape(f)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateFolder(destFolder)
	if err != nil {
		log.Printf("Validation failed for folder: '%s' - %s", com.SanitiseLogString(destFolder), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve destination database name
	d = r.PostFormValue("destdbname")
	destDBName, err := url.QueryUnescape(d)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateDB(destDBName)
	if err != nil {
		log.Printf("Validation failed for database name '%s': %s", com.SanitiseLogString(destDBName), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve destination branch name
	a = r.PostFormValue("destbranch")
	destBranch, err := url.QueryUnescape(a)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateBranchName(destBranch)
	if err != nil {
		log.Printf("Validation failed for branch name '%s': %s", com.SanitiseLogString(destBranch), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Validate the MR title
	tl := r.PostFormValue("title")
	if tl == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Title can't be blank")
		return
	}
	title, err := url.QueryUnescape(tl)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateDiscussionTitle(title)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Invalid characters in the merge request title")
		return
	}

	// Validate the MR description
	t := r.PostFormValue("desc")
	if t == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Merge request description can't be empty")
		return
	}
	descrip, err := url.QueryUnescape(t)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.Validate.Var(title, "markdownsource")
	if err != nil {
		w.WriteHeader(http.StatusUnauthorized)
		fmt.Fprint(w, "Invalid characters in the description field")
		return
	}

	// Make sure none of the required fields is empty
	if srcOwner == "" || srcFolder == "" || srcDBName == "" || srcBranch == "" || destOwner == "" || destFolder ==
		"" || destDBName == "" || destBranch == "" || title == "" || descrip == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Some of the (required) supplied fields are empty")
		return
	}

	// Check the databases exist
	srcExists, err := com.CheckDBPermissions(loggedInUser, srcOwner, srcFolder, srcDBName, false) // We don't require write access since MRs are considered public
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	destExists, err := com.CheckDBPermissions(loggedInUser, destOwner, destFolder, destDBName, false) // We don't require write access since MRs are considered public
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	if !srcExists || !destExists {
		w.WriteHeader(http.StatusNotFound)
		fmt.Fprint(w, "Invalid database.  One of the source or destination databases doesn't exist")
		return
	}

	// Get the details of the commits for the MR
	mrDetails := com.MergeRequestEntry{
		DestBranch:   destBranch,
		SourceBranch: srcBranch,
		SourceDBName: srcDBName,
		SourceFolder: srcFolder,
		SourceOwner:  srcOwner,
	}
	var ancestorID string
	ancestorID, mrDetails.Commits, _, err = com.GetCommonAncestorCommits(srcOwner, srcFolder, srcDBName, srcBranch,
		destOwner, destFolder, destDBName, destBranch)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}

	// Make sure the source branch will cleanly apply to the destination.  eg the destination branch hasn't received
	// additional commits since the source was forked
	if ancestorID == "" {
		w.WriteHeader(http.StatusConflict)
		fmt.Fprint(w, "Source branch is not a direct descendent of the destination branch.  Cannot merge.")
		return
	}

	// Create the merge request in PostgreSQL
	var x struct {
		ID int `json:"mr_id"`
	}
	x.ID, err = com.StoreDiscussion(destOwner, destFolder, destDBName, loggedInUser, title, descrip, com.MERGE_REQUEST,
		mrDetails)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}

	// Generate an event about the new merge request
	details := com.EventDetails{
		DBName:   destDBName,
		DiscID:   x.ID,
		Folder:   destFolder,
		Owner:    destOwner,
		Title:    title,
		Type:     com.EVENT_NEW_MERGE_REQUEST,
		URL:      fmt.Sprintf("/merge/%s%s%s?id=%d", url.PathEscape(destOwner), destFolder, url.PathEscape(destDBName), x.ID),
		UserName: loggedInUser,
	}
	err = com.NewEvent(details)
	if err != nil {
		log.Printf("Error when creating a new event: %s\n", err.Error())
		return
	}

	// Invalidate the memcache data for the destination database, so the new MR count gets picked up
	err = com.InvalidateCacheEntry(loggedInUser, destOwner, destFolder, destDBName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Indicate success to the caller, and return the ID # of the new merge request
	y, err := json.MarshalIndent(x, "", " ")
	if err != nil {
		log.Println(err)
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	w.WriteHeader(http.StatusOK)
	fmt.Fprint(w, string(y))
}

func createTagHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		errorPage(w, r, http.StatusUnauthorized, "You need to be logged in")
		return
	}

	// Extract and validate the form variables
	dbOwner, dbName, commit, err := com.GetFormUDC(r)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Missing or incorrect data supplied")
		return
	}
	tagName, err := com.GetFormTag(r)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Missing or incorrect tag name")
		return
	}

	// If given, validate the tag description field
	td := r.PostFormValue("tagdesc") // Optional
	var tagDesc string
	if td != "" {
		err = com.Validate.Var(td, "markdownsource")
		if err != nil {
			errorPage(w, r, http.StatusBadRequest, "Invalid characters in tag description")
			return
		}
		tagDesc = td
	}

	// Validate the tag type field
	tagType := r.PostFormValue("tagtype")
	if tagType != "tag" && tagType != "release" {
		errorPage(w, r, http.StatusBadRequest, "Unknown tag type")
		return
	}

	// Check if the requested database exists
	dbFolder := "/"
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	if !exists {
		errorPage(w, r, http.StatusNotFound, fmt.Sprintf("Database '%s%s%s' doesn't exist", dbOwner, dbFolder,
			dbName))
		return
	}

	// Retrieve the user details
	usr, err := com.User(loggedInUser)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, "An error occurred when retrieving user details")
	}

	// Create a new tag or release as appropriate
	if tagType == "release" {
		// * It's a release *

		// Read the releases list from the database
		rels, err := com.GetReleases(dbOwner, dbFolder, dbName)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}

		// Ensure the release doesn't already exist
		if _, ok := rels[tagName]; ok {
			errorPage(w, r, http.StatusConflict, "A release of that name already exists!")
			return
		}

		// Retrieve the size of the database for this release
		var tmp com.SQLiteDBinfo
		err = com.DBDetails(&tmp, loggedInUser, dbOwner, dbFolder, dbName, commit)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}
		size := tmp.Info.DBEntry.Size

		// Create the release
		newRel := com.ReleaseEntry{
			Commit:        commit,
			Date:          time.Now(),
			Description:   tagDesc,
			ReleaserEmail: usr.Email,
			ReleaserName:  usr.DisplayName,
			Size:          size,
		}
		rels[tagName] = newRel

		// Store it in PostgreSQL
		err = com.StoreReleases(dbOwner, dbFolder, dbName, rels)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}

		// Invalidate the memcache data for the database
		err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
		if err != nil {
			// Something went wrong when invalidating memcached entries for the database
			log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
			return
		}

		// Bounce to the releases page
		http.Redirect(w, r, fmt.Sprintf("/releases/%s%s%s", loggedInUser, dbFolder, dbName), http.StatusSeeOther)
		return
	}

	// * It's a tag *

	// Read the tags list from the database
	tags, err := com.GetTags(dbOwner, dbFolder, dbName)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Make sure the tag doesn't already exist
	if _, ok := tags[tagName]; ok {
		errorPage(w, r, http.StatusConflict, "A tag of that name already exists!")
		return
	}

	// Create the tag
	newTag := com.TagEntry{
		Commit:      commit,
		Date:        time.Now(),
		Description: tagDesc,
		TaggerEmail: usr.Email,
		TaggerName:  usr.DisplayName,
	}
	tags[tagName] = newTag

	// Store it in PostgreSQL
	err = com.StoreTags(dbOwner, dbFolder, dbName, tags)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Invalidate the memcache data for the database, so the new tag count gets picked up
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Bounce to the tags page
	http.Redirect(w, r, fmt.Sprintf("/tags/%s%s%s", loggedInUser, dbFolder, dbName), http.StatusSeeOther)
}

func createUserHandler(w http.ResponseWriter, r *http.Request) {
	// Make sure this user creation session is valid
	sess, err := store.Get(r, "user-reg")
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, err.Error())
		return
	}
	va := sess.Values["registrationinprogress"]
	if va == nil {
		// This isn't a valid username selection session, so abort
		errorPage(w, r, http.StatusBadRequest, "Invalid user creation session")
		return
	}
	validRegSession := va.(bool)
	if validRegSession != true {
		// This isn't a valid username selection session, so abort
		errorPage(w, r, http.StatusBadRequest, "Invalid user creation session")
		return
	}

	// Retrieve the registration data
	var auth0ID, avatarURL, email, displayName string
	au := sess.Values["auth0id"]
	if au != nil {
		auth0ID = au.(string)
	} else {
		errorPage(w, r, http.StatusBadRequest, "Invalid user creation id")
		return
	}
	av, ok := sess.Values["avatar"]
	if ok {
		avatarURL = av.(string)
	}
	em := sess.Values["email"]
	if em != nil {
		email = em.(string)
	} else {
		errorPage(w, r, http.StatusBadRequest, "Invalid user creation email")
		return
	}

	// Gather submitted form data (if any)
	err = r.ParseForm()
	if err != nil {
		log.Printf("Error when parsing user creation data: %s\n", err)
		errorPage(w, r, http.StatusBadRequest, "Error when parsing user creation data")
		return
	}
	userName := r.PostFormValue("username")

	// Ensure username was given
	if userName == "" {
		// No, so render the username selection page
		selectUserNamePage(w, r)
		return
	}

	// Validate the user supplied username
	err = com.ValidateUser(userName)
	if err != nil {
		log.Printf("Username failed validation: %s", err)

		// Note : gorilla/sessions uses MaxAge < 0 to mean "delete this session"
		sess.Options.MaxAge = -1
		err = sess.Save(r, w)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error()+" Username failed validation")
			return
		}

		// Alert the user to the validation problem
		errorPage(w, r, http.StatusInternalServerError, "Username failed validation")
		return
	}

	// Ensure the username isn't a reserved one
	err = com.ReservedUsernamesCheck(userName)
	if err != nil {
		log.Println(com.SanitiseLogString(err.Error()))

		// Note : gorilla/sessions uses MaxAge < 0 to mean "delete this session"
		sess.Options.MaxAge = -1
		err2 := sess.Save(r, w)
		if err2 != nil {
			// Try to display both errors
			errorPage(w, r, http.StatusInternalServerError, err2.Error()+" "+err.Error())
			return
		}

		// Alert the user to the ReservedUsernamesCheck() failure
		errorPage(w, r, http.StatusBadRequest, err.Error())
		return
	}

	// Check if the username is already in our system
	exists, err := com.CheckUserExists(userName)
	if err != nil {
		// Note : gorilla/sessions uses MaxAge < 0 to mean "delete this session"
		sess.Options.MaxAge = -1
		err = sess.Save(r, w)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error()+" Username check failed")
			return
		}

		// Alert the username check failure
		errorPage(w, r, http.StatusInternalServerError, "Username check failed")
		return
	}
	if exists {
		// Note : gorilla/sessions uses MaxAge < 0 to mean "delete this session"
		sess.Options.MaxAge = -1
		err = sess.Save(r, w)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error()+" That username is already taken")
			return
		}

		// Let the user know their desired username is not available
		errorPage(w, r, http.StatusConflict, "That username is already taken")
		return
	}

	// If present, validate the users' full name
	if displayName != "" {
		err = com.Validate.Var(displayName, "required,displayname,min=1,max=80")
		if err != nil {
			log.Printf("Display name value failed validation: %s\n", err)
			errorPage(w, r, http.StatusBadRequest, "Error when parsing full name value")
			return
		}
	}

	// If present, validate the email address
	if email != "" {
		err = com.Validate.Var(email, "email")
		if err != nil {
			// Check for the special case of username@server, which may fail standard email validation checks
			// eg username@localhost, won't validate as an email address, but should be accepted anyway
			serverName := strings.Split(com.Conf.Web.ServerName, ":")
			em := fmt.Sprintf("%s@%s", userName, serverName[0])
			if email != em {
				log.Printf("Email value failed validation: %s\n", err)
				errorPage(w, r, http.StatusBadRequest, "Error when parsing email value")
				return
			}
		}
	}

	// Add the user to the system
	// NOTE: We generate a random password here (for now).  We may remove the password field itself from the
	// database at some point, depending on whether we continue to support local database users
	err = com.AddUser(auth0ID, userName, com.RandomString(32), email, displayName, avatarURL)
	if err != nil {
		// Note : gorilla/sessions uses MaxAge < 0 to mean "delete this session"
		sess.Options.MaxAge = -1
		err = sess.Save(r, w)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error()+" Something went wrong during user creation")
			return
		}

		// Alert the user to the problem
		errorPage(w, r, http.StatusInternalServerError, "Something went wrong during user creation")
		return
	}

	// Remove the temporary username selection session data
	sess.Options.MaxAge = -1
	err = sess.Save(r, w)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Create normal session cookie for the user
	sess, err = store.Get(r, "dbhub-user")
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, err.Error())
		return
	}
	sess.Values["UserName"] = userName
	sess.Save(r, w)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// User creation completed, so bounce to the user profile page
	http.Redirect(w, r, "/"+userName, http.StatusSeeOther)
}

// This is called from the username selection page, to check if a name is available.
func checkNameHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve the potential username from the URL
	userName := r.FormValue("name")

	// Validate the user supplied username
	err := com.ValidateUser(userName)
	if err != nil {
		fmt.Fprint(w, "n")
		return
	}

	// Ensure the username isn't a reserved one
	err = com.ReservedUsernamesCheck(userName)
	if err != nil {
		fmt.Fprint(w, "n")
		return
	}

	// Check if the username is already in our system
	exists, err := com.CheckUserExists(userName)
	if err != nil {
		fmt.Fprint(w, "n")
		return
	}
	if exists {
		fmt.Fprint(w, "n")
		return
	}

	// The username is available
	fmt.Fprint(w, "y")
	return
}

// This is called from the username selection page, to check if a name is available.
func checkUserExistsHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve the username from the URL
	userName := r.FormValue("name")

	// Validate the username
	err := com.ValidateUser(userName)
	if err != nil {
		return
	}

	// Check if the username exists
	exists, err := com.CheckUserExists(userName)
	if err != nil {
		return
	}
	if exists {
		fmt.Fprint(w, "y")
		return
	}

	// The username does not exist
	fmt.Fprint(w, "n")
	return
}

// This function deletes a branch.
func deleteBranchHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Delete Branch handler"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbOwner := strings.ToLower(usr)

	// Check if a branch name was requested
	branchName, err := com.GetFormBranch(r)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// If any of the required values were empty, indicate failure
	if branchName == "" || dbFolder == "" || dbName == "" || dbOwner == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if !exists {
		log.Printf("%s: Validation failed for database to delete: %s", pageName, err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Load the existing branchHeads for the database
	branchList, err := com.GetBranches(loggedInUser, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Make sure the given branch exists
	branch, ok := branchList[branchName]
	if !ok {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Make sure the branch being deleted isn't the default one
	defBranch, err := com.GetDefaultBranchName(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if defBranch == branchName {
		w.WriteHeader(http.StatusConflict)
		return
	}

	// Make sure that deleting this branch wouldn't result in any isolated tags or releases.  For example, when there
	// is a tag or release on a commit which is only in this branch, deleting the branch would leave the tag or
	// release in place with no way to reach it

	// Get the commit list for the database
	commitList, err := com.GetCommitList(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Get the tag list for the database
	tags, err := com.GetTags(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Get the release list for the database
	rels, err := com.GetReleases(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// If the database has tags, walk the commit history for the branch checking if any of the tags are on commits in
	// this branch
	branchTags := make(map[string]string)
	if len(tags) > 0 {
		// Walk the commit history for the branch checking if any of the tags are on commits in this branch
		c, ok := commitList[branch.Commit]
		if !ok {
			log.Printf("Error when checking for isolated tags while deleting branch '%s' of database "+
				"'%s%s%s'\n", com.SanitiseLogString(branchName), com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName))
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
		for tName, tEntry := range tags {
			// Scan through the tags, checking if any of them are for this commit
			if tEntry.Commit == c.ID {
				// It's a match, so add this tag to the list of tags on this branch
				branchTags[tName] = c.ID
			}
		}
		for c.Parent != "" {
			c, ok = commitList[c.Parent]
			if !ok {
				log.Printf("Error when checking for isolated tags while deleting branch '%s' of database "+
					"'%s%s%s'\n", com.SanitiseLogString(branchName), com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName))
				w.WriteHeader(http.StatusInternalServerError)
				return
			}
			for tName, tEntry := range tags {
				// Scan through the tags, checking if any of them are for this commit
				if tEntry.Commit == c.ID {
					// It's a match, so add this tag to the list of tags on this branch
					branchTags[tName] = c.ID
				}
			}
		}

		// For any tags on commits in this branch, check if they're also on other branches
		if len(branchTags) > 0 {
			for bName, bEntry := range branchList {
				if bName == branchName {
					// We're only checking "other branches"
					continue
				}

				// If there are no tags left to check, we might as well stop further looping
				if len(branchTags) == 0 {
					break
				}

				c := commitList[bEntry.Commit]
				for tName, tCommit := range branchTags {
					if c.ID == tCommit {
						// This commit matches a tag, so remove the tag from the list
						delete(branchTags, tName)
					}
				}
				for c.Parent != "" {
					c, ok = commitList[c.Parent]
					if !ok {
						log.Printf("Error when checking for isolated tags while deleting branch '%s' of "+
							"database '%s%s%s'\n", com.SanitiseLogString(branchName), com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName))
						w.WriteHeader(http.StatusInternalServerError)
						return
					}
					for tName, tCommit := range branchTags {
						if c.ID == tCommit {
							// This commit matches a tag, so remove the tag from the list
							delete(branchTags, tName)
						}
					}
				}
			}
		}

		// If there are any tags left over which aren't on other branches, abort this branch deletion and tell the user
		if len(branchTags) > 0 {
			var conflictedTags string
			for tName := range branchTags {
				if conflictedTags == "" {
					conflictedTags = tName
				} else {
					conflictedTags += ", " + tName
				}
			}

			w.WriteHeader(http.StatusConflict)
			if len(branchTags) > 1 {
				w.Write([]byte(fmt.Sprintf("You need to delete the tags '%s' before you can delete this branch",
					conflictedTags)))
			} else {
				w.Write([]byte(fmt.Sprintf("You need to delete the tag '%s' before you can delete this branch",
					conflictedTags)))
			}
			return
		}
	}

	// If the database has releases, walk the commit history for the branch checking if any of the releases are on
	// commits in this branch
	branchRels := make(map[string]string)
	if len(rels) > 0 {
		// Walk the commit history for the branch checking if any of the releases are on commits in this branch
		c, ok := commitList[branch.Commit]
		if !ok {
			log.Printf("Error when checking for isolated releases while deleting branch '%s' of database "+
				"'%s%s%s'\n", com.SanitiseLogString(branchName), com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName))
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
		for rName, rEntry := range rels {
			// Scan through the releases, checking if any of them are for this commit
			if rEntry.Commit == c.ID {
				// It's a match, so add this release to the list of releases on this branch
				branchRels[rName] = c.ID
			}
		}
		for c.Parent != "" {
			c, ok = commitList[c.Parent]
			if !ok {
				log.Printf("Error when checking for isolated releases while deleting branch '%s' of database "+
					"'%s%s%s'\n", com.SanitiseLogString(branchName), com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName))
				w.WriteHeader(http.StatusInternalServerError)
				return
			}
			for rName, rEntry := range rels {
				// Scan through the releases, checking if any of them are for this commit
				if rEntry.Commit == c.ID {
					// It's a match, so add this release to the list of releases on this branch
					branchRels[rName] = c.ID
				}
			}
		}

		// For any releases on commits in this branch, check if they're also on other branches
		if len(branchRels) > 0 {
			for bName, bEntry := range branchList {
				if bName == branchName {
					// We're only checking "other branches"
					continue
				}

				// If there are no releases left to check, we might as well stop further looping
				if len(branchRels) == 0 {
					break
				}

				c := commitList[bEntry.Commit]
				for rName, rCommit := range branchRels {
					if c.ID == rCommit {
						// This commit matches a release, so remove the release from the list
						delete(branchRels, rName)
					}
				}
				for c.Parent != "" {
					c, ok = commitList[c.Parent]
					if !ok {
						log.Printf("Error when checking for isolated releases while deleting branch '%s' of "+
							"database '%s%s%s'\n", com.SanitiseLogString(branchName), com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName))
						w.WriteHeader(http.StatusInternalServerError)
						return
					}
					for rName, rCommit := range branchRels {
						if c.ID == rCommit {
							// This commit matches a release, so remove the release from the list
							delete(branchRels, rName)
						}
					}
				}
			}
		}

		// If there are any releases left over which aren't on other branches, abort this branch deletion and tell the user
		if len(branchRels) > 0 {
			var conflictedRels string
			for rName := range branchRels {
				if conflictedRels == "" {
					conflictedRels = rName
				} else {
					conflictedRels += ", " + rName
				}
			}

			w.WriteHeader(http.StatusConflict)
			if len(branchRels) > 1 {
				w.Write([]byte(fmt.Sprintf("You need to delete the releases '%s' before you can delete this branch",
					conflictedRels)))
			} else {
				w.Write([]byte(fmt.Sprintf("You need to delete the release '%s' before you can delete this branch",
					conflictedRels)))
			}
			return
		}
	}

	// Make a list of commits in this branch
	lst := map[string]bool{}
	c, ok := commitList[branch.Commit]
	if !ok {
		log.Printf("Error when creating commit list while deleting branch '%s' of database '%s%s%s'\n",
			com.SanitiseLogString(branchName), com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName))
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	lst[c.ID] = true
	for c.Parent != "" {
		c, ok = commitList[c.Parent]
		if !ok {
			log.Printf("Error when creating commit list while deleting branch '%s' of database '%s%s%s'\n",
				com.SanitiseLogString(branchName), com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName))
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
		lst[c.ID] = true
	}

	// For each commit, determine if it's only on this branch, and will need to be deleted after the branch
	for bName, bEntry := range branchList {
		if bName == branchName {
			// We only run this comparison from "other branches", not the branch we're deleting
			continue
		}

		// If there are no commits left to check, we might as well stop further looping
		if len(lst) == 0 {
			break
		}

		c, ok = commitList[bEntry.Commit]
		if !ok {
			err = fmt.Errorf("Broken commit history encountered when checking for commits while deleting "+
				"branch '%s' of database '%s%s%s'\n", branchName, dbOwner, dbFolder, dbName)
			log.Print(err.Error()) // Broken commit history is pretty serious, so we log it for admin investigation
			return
		}
		for delCommit := range lst {
			if c.ID == delCommit {
				// The commit is also on another branch, so we *must not* delete the commit afterwards
				delete(lst, c.ID)
			}
		}
		for c.Parent != "" {
			c, ok = commitList[c.Parent]
			if !ok {
				err = fmt.Errorf("Broken commit history encountered when checking for commits while "+
					"deleting branch '%s' of database '%s%s%s'\n", branchName, dbOwner, dbFolder, dbName)
				log.Print(err.Error()) // Broken commit history is pretty serious, so we log it for admin investigation
				return
			}
			for delCommit := range lst {
				if c.ID == delCommit {
					// The commit is also on another branch, so we *must not* delete the commit afterwards
					delete(lst, c.ID)
				}
			}
		}
	}

	// Delete the branch
	delete(branchList, branchName)
	err = com.StoreBranches(dbOwner, dbFolder, dbName, branchList)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Delete the left over commits
	// TODO: We may want to consider clearing any memcache entries for the deleted commits too
	for cid := range lst {
		delete(commitList, cid)
	}
	err = com.StoreCommits(dbOwner, dbFolder, dbName, commitList)
	if err != nil {
		log.Printf("Error when updating commit list while deleting branch '%s' of database '%s%s%s': %s\n",
			com.SanitiseLogString(branchName), com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName), err.Error())
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Invalidate the memcache data for the database, so the new branch count gets picked up
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Update succeeded
	w.WriteHeader(http.StatusOK)
}

// This function deletes a given comment from a discussion.
func deleteCommentHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		fmt.Fprint(w, "You need to be logged in")
		return
	}

	// Extract and validate the form variables
	dbOwner, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Missing or incorrect data supplied")
		return
	}

	// Ensure a discussion ID was given
	a := r.PostFormValue("discid")
	if a == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Missing discussion id")
		return
	}
	discID, err := strconv.Atoi(a)
	if err != nil {
		log.Printf("Error converting string '%s' to integer in function '%s': %s\n", com.SanitiseLogString(a),
			com.GetCurrentFunctionName(), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Error when parsing discussion id value")
		return
	}

	// Ensure a comment ID was given
	a = r.PostFormValue("comid")
	if a == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Missing comment id")
		return
	}
	comID, err := strconv.Atoi(a)
	if err != nil {
		log.Printf("Error converting string '%s' to integer in function '%s': %s\n", com.SanitiseLogString(a),
			com.GetCurrentFunctionName(), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Error when parsing comment id value")
		return
	}

	// Check if the requested database exists
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, false) // We don't require write access since MRs are considered public
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	if !exists {
		w.WriteHeader(http.StatusNotFound)
		fmt.Fprintf(w, "Database '%s%s%s' doesn't exist", dbOwner, dbFolder, dbName)
		return
	}

	// Check if the logged in user is allowed to delete the requested comment
	deleteAllowed := false
	if strings.ToLower(dbOwner) == strings.ToLower(loggedInUser) {
		// The database owner can delete any discussion comment on their databases
		deleteAllowed = true
	} else {
		// Retrieve the details for the requested comment, so we can check if the logged in user is the comment creator
		rq, err := com.DiscussionComments(dbOwner, dbFolder, dbName, discID, comID)
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			fmt.Fprint(w, err.Error())
			return
		}
		if strings.ToLower(rq[0].Commenter) == strings.ToLower(loggedInUser) {
			deleteAllowed = true
		}
	}

	// If the logged in user isn't allowed to delete the requested comment, then reject the request
	if !deleteAllowed {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Delete the comment from PostgreSQL
	err = com.DeleteComment(dbOwner, dbFolder, dbName, discID, comID)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	w.WriteHeader(http.StatusOK)
}

// This function deletes the latest commit from a given branch.
func deleteCommitHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Delete commit handler"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbOwner := strings.ToLower(usr)

	// Validate the supplied commit ID
	commit, err := com.GetFormCommit(r)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Validate the supplied branch name
	branchName, err := com.GetFormBranch(r)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// If any of the required values were empty, indicate failure
	if branchName == "" || dbFolder == "" || dbName == "" || dbOwner == "" || commit == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if !exists {
		log.Printf("%s: Validation failed for database name: %s", pageName, err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Load the existing branchHeads for the database
	branches, err := com.GetBranches(loggedInUser, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Make sure the given branch exists
	b, ok := branches[branchName]
	if !ok {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Unknown branch name"))
		return
	}

	// Check that the given commit matches the head commit of the branch
	if b.Commit != commit {
		w.WriteHeader(http.StatusConflict)
		w.Write([]byte("Only the most recent commit for a branch can be deleted"))
		return
	}

	// Determine the commit ID we'll be rewinding to
	commitList, err := com.GetCommitList(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	c, ok := commitList[commit]
	if !ok {
		w.WriteHeader(http.StatusNotFound)
		w.Write([]byte("Requested commit not found"))
		return
	}
	if c.Parent == "" {
		w.WriteHeader(http.StatusConflict)
		w.Write([]byte("Requested commit has no ancestors.  Not going to delete it"))
		return
	}
	prevCommit := c.Parent

	// If we're working on the default branch, check if the default table is present in the prior commit's version
	// of the database.  If it's not, we need to clear the default table value
	defBranch, err := com.GetDefaultBranchName(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if branchName == defBranch {
		// * Retrieve the list of tables present in the prior commit *
		bkt, id, _, err := com.MinioLocation(dbOwner, dbFolder, dbName, prevCommit, loggedInUser)
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			return
		}

		// Get a handle from Minio for the SQLite database object
		sdb, err := com.OpenSQLiteDatabase(bkt, id)
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			return
		}

		// Automatically close the SQLite database when this function finishes
		defer sdb.Close()

		// Retrieve the list of tables in the database
		sTbls, err := com.TablesAndViews(sdb, fmt.Sprintf("%s%s%s", dbOwner, dbFolder, dbName))
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}

		// Retrieve the default table name for the database
		defTbl, err := com.GetDefaultTableName(dbOwner, dbFolder, dbName)
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
		defFound := false
		for _, j := range sTbls {
			if j == defTbl {
				defFound = true
			}
		}
		if !defFound {
			// The default table is present in the previous commit, so we clear the default table value
			err = com.StoreDefaultTableName(dbOwner, dbFolder, dbName, "")
			if err != nil {
				w.WriteHeader(http.StatusInternalServerError)
				return
			}
		}
	}

	// Delete the commit
	iTags, iRels, err := com.DeleteBranchHistory(dbOwner, dbFolder, dbName, branchName, prevCommit)
	if err != nil {
		if (len(iTags) > 0) || (len(iRels) > 0) {
			msg := fmt.Sprintln("You need to delete the following tags and releases before the commit can be " +
				"deleted:")
			var rList, tList string
			if len(iTags) > 0 {
				// Would-be-isolated tags were identified.  Warn the user.
				msg += "  TAGS: "
				for _, tName := range iTags {
					if tList == "" {
						msg += fmt.Sprintf("'%s'", tName)
					} else {
						msg += fmt.Sprintf(", '%s'", tName)
					}
				}
			}
			if len(iRels) > 0 {
				// Would-be-isolated releases were identified.  Warn the user.
				msg += "  RELEASES: "
				for _, rName := range iRels {
					if rList == "" {
						msg += fmt.Sprintf("'%s'", rName)
					} else {
						msg += fmt.Sprintf(", '%s'", rName)
					}
				}
			}
			w.WriteHeader(http.StatusConflict)
			w.Write([]byte(msg))
			return
		}
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte("Commit deletion failed, internal server error"))
		return
	}

	// Invalidate the memcache data for the database, so the new branch count gets picked up
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Update succeeded
	w.WriteHeader(http.StatusOK)
}

// This function deletes a database.
func deleteDatabaseHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Delete Database handler"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		fmt.Fprint(w, "You need to be logged in")
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Validation failed for owner or database name")
		return
	}
	dbOwner := strings.ToLower(usr)

	// If any of the required values were empty, indicate failure
	if dbFolder == "" || dbName == "" || dbOwner == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Owner, folder, or database name values() missing")
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, "Internal server error")
		return
	}
	if !exists {
		log.Printf("%s: Missing database for '%s%s%s' when attempting deletion\n", pageName, com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder),
			com.SanitiseLogString(dbName))
		w.WriteHeader(http.StatusNotFound)
		fmt.Fprint(w, "Internal server error")
		return
	}

	// Make sure the database is owned by the logged in user. eg prevent changes to other people's databases
	if strings.ToLower(dbOwner) != strings.ToLower(loggedInUser) {
		w.WriteHeader(http.StatusUnauthorized)
		fmt.Fprint(w, "You don't have permission to delete that database")
		return
	}

	// Invalidate the memcache data for the database, so the new branch count gets picked up
	// Note - on one hand this is a race condition, as new cache data could get into memcache between this invalidation
	// call and the delete.  On the other hand, once it's deleted the invalidation function would itself fail due to
	// needing the database to be present so it can look up the commit list.  At least doing the invalidation here lets
	// us clear stale data (hopefully) for the vast majority of the time
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Delete the database
	err = com.DeleteDatabase(dbOwner, dbFolder, dbName)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, "Internal server error")
		return
	}

	// Update succeeded
	w.WriteHeader(http.StatusOK)
}

// This function deletes a release.
func deleteReleaseHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Delete Release handler"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbOwner := strings.ToLower(usr)

	// Ensure a release name was supplied
	relName, err := com.GetFormRelease(r)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// If any of the required values were empty, indicate failure
	if relName == "" || dbFolder == "" || dbName == "" || dbOwner == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if !exists {
		log.Printf("%s: Validation failed for database name: %s", pageName, err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Load the existing releases for the database
	releases, err := com.GetReleases(loggedInUser, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Make sure the given tag exists
	if _, ok := releases[relName]; !ok {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Delete the release
	delete(releases, relName)
	err = com.StoreReleases(dbOwner, dbFolder, dbName, releases)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Invalidate the memcache data for the database, so the new release count gets picked up
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Update succeeded
	w.WriteHeader(http.StatusOK)
}

// This function deletes a tag.
func deleteTagHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Delete Tag handler"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbOwner := strings.ToLower(usr)

	// Ensure a tag name was supplied
	tagName, err := com.GetFormTag(r)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// If any of the required values were empty, indicate failure
	if tagName == "" || dbFolder == "" || dbName == "" || dbOwner == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if !exists {
		log.Printf("%s: Validation failed for database name: %s", pageName, err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Load the existing tags for the database
	tags, err := com.GetTags(loggedInUser, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Make sure the given tag exists
	if _, ok := tags[tagName]; !ok {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Delete the tag
	delete(tags, tagName)
	err = com.StoreTags(dbOwner, dbFolder, dbName, tags)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Invalidate the memcache data for the database, so the new tag count gets picked up
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Update succeeded
	w.WriteHeader(http.StatusOK)
}

// Returns the list of commits that are different between a source and destination database/branch
func diffCommitListHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, _, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Retrieve source owner
	o := r.PostFormValue("sourceowner")
	srcOwner, err := url.QueryUnescape(o)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateUser(srcOwner)
	if err != nil {
		log.Printf("Validation failed for username: '%s'- %s", com.SanitiseLogString(srcOwner), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve source folder
	f := r.PostFormValue("sourcefolder")
	srcFolder, err := url.QueryUnescape(f)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateFolder(srcFolder)
	if err != nil {
		log.Printf("Validation failed for folder: '%s' - %s", com.SanitiseLogString(srcFolder), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve source database name
	d := r.PostFormValue("sourcedbname")
	srcDBName, err := url.QueryUnescape(d)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateDB(srcDBName)
	if err != nil {
		log.Printf("Validation failed for database name '%s': %s", com.SanitiseLogString(srcDBName), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve source branch name
	a := r.PostFormValue("sourcebranch")
	srcBranch, err := url.QueryUnescape(a)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateBranchName(srcBranch)
	if err != nil {
		log.Printf("Validation failed for branch name '%s': %s", com.SanitiseLogString(srcBranch), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve destination owner
	o = r.PostFormValue("destowner")
	destOwner, err := url.QueryUnescape(o)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateUser(destOwner)
	if err != nil {
		log.Printf("Validation failed for username: '%s'- %s", com.SanitiseLogString(destOwner), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve destination folder
	f = r.PostFormValue("destfolder")
	destFolder, err := url.QueryUnescape(f)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateFolder(destFolder)
	if err != nil {
		log.Printf("Validation failed for folder: '%s' - %s", com.SanitiseLogString(destFolder), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve destination database name
	d = r.PostFormValue("destdbname")
	destDBName, err := url.QueryUnescape(d)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateDB(destDBName)
	if err != nil {
		log.Printf("Validation failed for database name '%s': %s", com.SanitiseLogString(destDBName), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Retrieve destination branch name
	a = r.PostFormValue("destbranch")
	destBranch, err := url.QueryUnescape(a)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	err = com.ValidateBranchName(destBranch)
	if err != nil {
		log.Printf("Validation failed for branch name '%s': %s", com.SanitiseLogString(destBranch), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}

	// Make sure none of the required fields is empty
	if srcOwner == "" || srcFolder == "" || srcDBName == "" || srcBranch == "" || destOwner == "" || destFolder ==
		"" || destDBName == "" || destBranch == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Some of the (required) supplied fields are empty")
		return
	}

	// Check the databases exist
	srcExists, err := com.CheckDBPermissions(loggedInUser, srcOwner, srcFolder, srcDBName, false)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	destExists, err := com.CheckDBPermissions(loggedInUser, destOwner, destFolder, destDBName, false)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	if !srcExists || !destExists {
		w.WriteHeader(http.StatusNotFound)
		fmt.Fprint(w, "Invalid database.  One of the source or destination databases doesn't exist")
		return
	}

	// Get the commit list diff
	ancestorID, cList, errType, err := com.GetCommonAncestorCommits(srcOwner, srcFolder, srcDBName, srcBranch, destOwner,
		destFolder, destDBName, destBranch)
	if err != nil && errType != http.StatusBadRequest {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}

	// Make sure the source branch will cleanly apply to the destination.  eg the destination branch hasn't received
	// additional commits since the source was forked
	if ancestorID == "" {
		w.WriteHeader(http.StatusConflict)
		fmt.Fprint(w, "Source branch is not a direct descendent of the destination branch.  Cannot create commit "+
			"list diff.")
		return
	}

	// * Retrieve the current licence for the destination branch *

	// Retrieve the commit ID for the destination branch
	destBranchList, err := com.GetBranches(destOwner, destFolder, destDBName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	b, ok := destBranchList[destBranch]
	if !ok {
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			fmt.Fprint(w, err.Error())
			return
		}
	}
	destCommitID := b.Commit

	// Retrieve the current licence for the destination branch, using the commit ID
	commitList, err := com.GetCommitList(destOwner, destFolder, destDBName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	destCommit, ok := commitList[destCommitID]
	if !ok {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, "Destination commit ID not found in commit list.")
		return
	}
	destLicenceSHA := destCommit.Tree.Entries[0].LicenceSHA

	// Convert the commit entries into something we can display in a commit list
	var x struct {
		CommitList []com.CommitData `json:"commit_list"`
	}
	for _, j := range cList {
		var c com.CommitData
		c.AuthorEmail = j.AuthorEmail
		c.AuthorName = j.AuthorName
		c.ID = j.ID
		c.Parent = j.Parent
		c.Message = j.Message
		c.Timestamp = j.Timestamp
		c.AuthorUsername, c.AuthorAvatar, err = com.GetUsernameFromEmail(j.AuthorEmail)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}
		if c.AuthorAvatar != "" {
			c.AuthorAvatar += "&s=18"
		}

		// Check for licence changes
		commitLicSHA := j.Tree.Entries[0].LicenceSHA
		if commitLicSHA != destLicenceSHA {
			lName, _, err := com.GetLicenceInfoFromSha256(srcOwner, commitLicSHA)
			if err != nil {
				errorPage(w, r, http.StatusInternalServerError, err.Error())
				return
			}
			c.LicenceChange = fmt.Sprintf("This commit includes a licence change to '%s'", lName)
		}
		x.CommitList = append(x.CommitList, c)
	}

	// Return the commit list
	y, err := json.MarshalIndent(x, "", " ")
	if err != nil {
		log.Println(err)
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	w.WriteHeader(http.StatusOK)
	fmt.Fprint(w, string(y))
}

func downloadCSVHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Download CSV"

	// Extract the username, database, table, and commit ID requested
	// NOTE - The commit ID is optional.  Without it, we just pick the latest commit from the (for now) default branch
	// TODO: Add support for passing in a specific branch, to get the latest commit for that instead
	dbOwner, dbName, dbTable, commitID, err := com.GetODTC(2, r) // 2 = Ignore "/x/download/" at the start of the URL
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, err.Error())
		return
	}

	// Abort if the table name was missing
	if dbTable == "" {
		log.Printf("%s: Missing table name\n", pageName)
		errorPage(w, r, http.StatusBadRequest, "Missing table name")
		return
	}

	// Retrieve session data (if any)
	loggedInUser, _, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Verify the given database exists and is ok to be downloaded (and get the Minio bucket + id while at it)
	bucket, id, _, err := com.MinioLocation(dbOwner, "/", dbName, commitID, loggedInUser)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Ensure the database being requested isn't overly large
	var tmp com.SQLiteDBinfo
	err = com.DBDetails(&tmp, loggedInUser, dbOwner, "/", dbName, commitID)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	size := tmp.Info.DBEntry.Size
	if size >= 100000000 {
		errorPage(w, r, http.StatusBadRequest, "CSV export not allowed for this database due to size restrictions.")
		return
	}

	// Get a handle from Minio for the database object
	sdb, err := com.OpenSQLiteDatabase(bucket, id)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, "Database query failed")
		return
	}

	// Automatically close the SQLite database when this function finishes
	defer sdb.Close()

	// Read the table data from the database object
	resultSet, err := com.ReadSQLiteDBCSV(sdb, dbTable)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, "Error reading table data from the database")
		return
	}

	// Was a user agent part of the request?
	var userAgent string
	if ua, ok := r.Header["User-Agent"]; ok {
		userAgent = strings.ToLower(ua[0])
	}

	// Check if the request came from a Windows based device.  If it did, it'll need CRLF line endings
	win := strings.Contains(userAgent, "windows")

	// Convert resultSet into CSV and send to the user
	w.Header().Set("Content-Disposition", fmt.Sprintf(`attachment; filename="%s.csv"`, dbTable))
	w.Header().Set("Content-Type", "text/csv")
	csvFile := csv.NewWriter(w)
	csvFile.UseCRLF = win
	err = csvFile.WriteAll(resultSet)
	if err != nil {
		log.Printf("%s: Error when generating CSV: %v\n", pageName, err)
		errorPage(w, r, http.StatusInternalServerError, "Error when generating CSV")
		return
	}
}

func downloadHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Download Handler"

	// NOTE - The commit ID is optional.  Without it, we just pick the latest commit from the (for now) default branch
	// TODO: Add support for passing in a specific branch, to get the latest commit for that instead
	dbOwner, dbName, commitID, err := com.GetODC(2, r) // 2 = Ignore "/x/download/" at the start of the URL
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, err.Error())
		return
	}
	dbFolder := "/"

	// Retrieve session data (if any)
	loggedInUser, _, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Return the requested database to the user
	var bytesWritten int64
	bytesWritten, err = com.DownloadDatabase(w, r, dbOwner, dbFolder, dbName, commitID, loggedInUser, "webui")
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Log the number of bytes written
	log.Printf("%s: '%s/%s' downloaded. %d bytes", pageName, com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbName), bytesWritten)
}

// Forks a database for the logged in user.
func forkDBHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve username, database name, and commit ID
	dbOwner, dbName, commitID, err := com.GetODC(2, r) // 2 = Ignore "/x/forkdb/" at the start of the URL
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, err.Error())
		return
	}
	dbFolder := "/"

	// Make sure a database commit ID was given
	if commitID == "" {
		errorPage(w, r, http.StatusBadRequest, "No database commit ID given")
		return
	}

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		// No logged in username, so nothing to update
		errorPage(w, r, http.StatusBadRequest, "To fork a database, you need to be logged in")
		return
	}

	// Check the user has access to the specific version of the source database requested
	allowed, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, false)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	if !allowed {
		errorPage(w, r, http.StatusNotFound, "You don't have access to the requested database")
		return
	}

	// Make sure the source and destination owners are different
	if strings.ToLower(loggedInUser) == strings.ToLower(dbOwner) {
		errorPage(w, r, http.StatusBadRequest, "Forking your own database in-place doesn't make sense")
		return
	}

	// Make sure the user doesn't have a database of the same name already
	// Note the use of "loggedInUser" for the 2nd parameter in this call, unlike using "dbOwner" in the call above
	exists, err := com.CheckDBPermissions(loggedInUser, loggedInUser, dbFolder, dbName, false)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	if exists {
		// Database of the same name already exists
		errorPage(w, r, http.StatusNotFound, "You already have a database of this name")
		return
	}

	// Add the forked database info to PostgreSQL
	_, err = com.ForkDatabase(dbOwner, dbFolder, dbName, loggedInUser)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Add the user to the watch list for the forked database
	if !exists {
		err = com.ToggleDBWatch(loggedInUser, loggedInUser, dbFolder, dbName)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}
	}

	// Invalidate the old memcached entry for the database
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Log the database fork
	log.Printf("Database '%s%s%s' forked to user '%s'\n", com.SanitiseLogString(dbOwner), dbFolder, com.SanitiseLogString(dbName), loggedInUser)

	// Bounce to the page of the forked database
	http.Redirect(w, r, fmt.Sprintf("/%s%s%s", loggedInUser, dbFolder, dbName), http.StatusSeeOther)
}

// Generates a client certificate for the user and gives it to the browser.
func generateCertHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		// No logged in user, so error out
		errorPage(w, r, http.StatusBadRequest, "Not logged in")
		return
	}

	// Generate a new certificate
	newCert, err := com.GenerateClientCert(loggedInUser)
	if err != nil {
		log.Printf("Error generating client certificate for user '%s': %s!\n", loggedInUser, err)
		errorPage(w, r, http.StatusInternalServerError, "Error generating client certificate")
		return
	}

	// Send the client certificate to the user
	w.Header().Set("Content-Disposition", fmt.Sprintf(`attachment; filename="%s.cert.pem"`, loggedInUser))
	// Note, don't use "application/x-x509-user-cert", otherwise the browser may try to install it!
	// Useful reference info: https://pki-tutorial.readthedocs.io/en/latest/mime.html
	w.Header().Set("Content-Type", "application/x-pem-file")
	w.Write(newCert)
	return
}

// Removes the logged in users session information.
func logoutHandler(w http.ResponseWriter, r *http.Request) {
	// Remove session info
	sess, err := store.Get(r, "dbhub-user")
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, err.Error())
		return
	}
	// Note : gorilla/sessions uses MaxAge < 0 to mean "delete this session"
	sess.Options.MaxAge = -1
	err = sess.Save(r, w)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Simulate logout for the test environment
	if com.Conf.Environment.Environment == "test" {
		com.Conf.Environment.UserOverride = ""
	}

	// Bounce to the front page
	// TODO: This should probably reload the existing page instead
	http.Redirect(w, r, "/", http.StatusSeeOther)
}

// Wrapper function to log incoming https requests.
func logReq(fn http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		// Check if user is logged in
		var loggedInUser string
		sess, err := store.Get(r, "dbhub-user")
		if err != nil {
			if err == memcache.ErrCacheMiss {
				// If the memcache session token is stale (eg memcached has been restarted), delete the session
				// TODO: This should probably look for the session token in persistent storage (eg PG) instead, so
				// TODO  restarts of memcached don't nuke everyone's saved sessions

				// Delete the session
				// Note : gorilla/sessions uses MaxAge < 0 to mean "delete this session"
				sess.Options.MaxAge = -1
				err = sess.Save(r, w)
				if err != nil {
					errorPage(w, r, http.StatusInternalServerError, err.Error())
					return
				}

				// Reload the page
				http.Redirect(w, r, fmt.Sprintf("%s", r.URL), http.StatusTemporaryRedirect)
			} else {
				errorPage(w, r, http.StatusBadRequest, err.Error())
				return
			}
		}
		u := sess.Values["UserName"]
		if u != nil {
			loggedInUser = u.(string)
		} else {
			loggedInUser = "-"
		}

		if com.Conf.Environment.Environment != "production" {
			loggedInUser = "default"
		}

		// Write request details to the request log
		fmt.Fprintf(reqLog, "%v - %s [%s] \"%s %s %s\" \"-\" \"-\" \"%s\" \"%s\"\n", r.RemoteAddr,
			loggedInUser, time.Now().Format(time.RFC3339Nano), r.Method, r.URL, r.Proto,
			r.Referer(), r.Header.Get("User-Agent"))

		// Call the original function
		fn(w, r)
	}
}

func main() {
	// Read server configuration
	var err error
	if err = com.ReadConfig(); err != nil {
		log.Fatalf("Configuration file problem\n\n%v", err)
	}

	// Set the temp dir environment variable
	err = os.Setenv("TMPDIR", com.Conf.DiskCache.Directory)
	if err != nil {
		log.Fatalf("Setting temp directory environment variable failed: '%s'\n", err.Error())
	}

	// Ensure the SQLite library is recent enough
	if com.SQLiteVersionNumber() < 3031000 {
		log.Fatalf("Aborting.  SQLite version is too old: %v, needs to be at least SQLite 3.31.0.\n ", sqlite.Version())
	}

	// Open the request log for writing
	reqLog, err = os.OpenFile(com.Conf.Web.RequestLog, os.O_CREATE|os.O_APPEND|os.O_WRONLY|os.O_SYNC, 0750)
	if err != nil {
		log.Fatalf("Error when opening request log: %s\n", err)
	}
	defer reqLog.Close()
	log.Printf("Request log opened: %s\n", com.Conf.Web.RequestLog)

	// Parse our template files
	tmpl = template.Must(template.New("templates").Delims("[[", "]]").ParseGlob(
		filepath.Join(com.Conf.Web.BaseDir, "webui", "templates", "*.html")))

	// Connect to Minio server
	err = com.ConnectMinio()
	if err != nil {
		log.Fatalf(err.Error())
	}

	// Connect to PostgreSQL server
	err = com.ConnectPostgreSQL()
	if err != nil {
		log.Fatalf(err.Error())
	}

	// Add the default user to the system
	err = com.AddDefaultUser()
	if err != nil {
		log.Fatalf(err.Error())
	}

	// Add the default licences to PostgreSQL
	err = com.AddDefaultLicences()
	if err != nil {
		log.Fatalf(err.Error())
	}

	// Connect to MQ server
	com.Conf.Live.Nodename = "WebUI server"
	com.AmqpChan, err = com.ConnectMQ()
	if err != nil {
		log.Fatal(err)
	}

	// Connect to the Memcached server
	err = com.ConnectCache()
	if err != nil {
		log.Fatalf(err.Error())
	}

	// Setup session storage
	store = gsm.NewMemcacheStore(com.MemcacheHandle(), "dbhub_", []byte(com.Conf.Web.SessionStorePassword))

	// Start the view count flushing routine in the background
	go com.FlushViewCount()

	// Start the status update processing goroutine in the background (will likely need moving into a separate daemon)
	go com.StatusUpdatesLoop()

	// Start the email sending goroutine in the background
	go com.SendEmails()

	// Our pages
	http.Handle("/", gz.GzipHandler(logReq(mainHandler)))
	http.Handle("/about", gz.GzipHandler(logReq(aboutPage)))
	http.Handle("/branches/", gz.GzipHandler(logReq(branchesPage)))
	http.Handle("/commits/", gz.GzipHandler(logReq(commitsPage)))
	http.Handle("/compare/", gz.GzipHandler(logReq(comparePage)))
	http.Handle("/confirmdelete/", gz.GzipHandler(logReq(confirmDeletePage)))
	http.Handle("/contributors/", gz.GzipHandler(logReq(contributorsPage)))
	http.Handle("/createbranch/", gz.GzipHandler(logReq(createBranchPage)))
	http.Handle("/creatediscuss/", gz.GzipHandler(logReq(createDiscussionPage)))
	http.Handle("/createtag/", gz.GzipHandler(logReq(createTagPage)))
	http.Handle("/diffs/", gz.GzipHandler(logReq(diffPage)))
	http.Handle("/discuss/", gz.GzipHandler(logReq(discussPage)))
	http.Handle("/forks/", gz.GzipHandler(logReq(forksPage)))
	http.Handle("/logout", gz.GzipHandler(logReq(logoutHandler)))
	http.Handle("/merge/", gz.GzipHandler(logReq(mergePage)))
	http.Handle("/pref", gz.GzipHandler(logReq(prefHandler)))
	http.Handle("/register", gz.GzipHandler(logReq(createUserHandler)))
	http.Handle("/releases/", gz.GzipHandler(logReq(releasesPage)))
	http.Handle("/selectusername", gz.GzipHandler(logReq(selectUserNamePage)))
	http.Handle("/settings/", gz.GzipHandler(logReq(settingsPage)))
	http.Handle("/stars/", gz.GzipHandler(logReq(starsPage)))
	http.Handle("/tags/", gz.GzipHandler(logReq(tagsPage)))
	http.Handle("/updates/", gz.GzipHandler(logReq(updatesPage)))
	http.Handle("/upload/", gz.GzipHandler(logReq(uploadPage)))
	http.Handle("/vis/", gz.GzipHandler(logReq(visualisePage)))
	http.Handle("/watchers/", gz.GzipHandler(logReq(watchersPage)))
	http.Handle("/x/apikeygen", gz.GzipHandler(logReq(apiKeyGenHandler)))
	http.Handle("/x/branchnames", gz.GzipHandler(logReq(branchNamesHandler)))
	http.Handle("/x/callback", gz.GzipHandler(logReq(auth0CallbackHandler)))
	http.Handle("/x/checkname", gz.GzipHandler(logReq(checkNameHandler)))
	http.Handle("/x/checkuserexists", gz.GzipHandler(logReq(checkUserExistsHandler)))
	http.Handle("/x/createbranch", gz.GzipHandler(logReq(createBranchHandler)))
	http.Handle("/x/createcomment/", gz.GzipHandler(logReq(createCommentHandler)))
	http.Handle("/x/creatediscuss", gz.GzipHandler(logReq(createDiscussHandler)))
	http.Handle("/x/createmerge/", gz.GzipHandler(logReq(createMergeHandler)))
	http.Handle("/x/createtag", gz.GzipHandler(logReq(createTagHandler)))
	http.Handle("/x/deletebranch/", gz.GzipHandler(logReq(deleteBranchHandler)))
	http.Handle("/x/deletecomment/", gz.GzipHandler(logReq(deleteCommentHandler)))
	http.Handle("/x/deletecommit/", gz.GzipHandler(logReq(deleteCommitHandler)))
	http.Handle("/x/deletedatabase/", gz.GzipHandler(logReq(deleteDatabaseHandler)))
	http.Handle("/x/deleterelease/", gz.GzipHandler(logReq(deleteReleaseHandler)))
	http.Handle("/x/deletetag/", gz.GzipHandler(logReq(deleteTagHandler)))
	http.Handle("/x/diffcommitlist/", gz.GzipHandler(logReq(diffCommitListHandler)))
	http.Handle("/x/download/", gz.GzipHandler(logReq(downloadHandler)))
	http.Handle("/x/downloadcsv/", gz.GzipHandler(logReq(downloadCSVHandler)))
	http.Handle("/x/execsql/", gz.GzipHandler(logReq(visExecuteSQL)))
	http.Handle("/x/forkdb/", gz.GzipHandler(logReq(forkDBHandler)))
	http.Handle("/x/gencert", gz.GzipHandler(logReq(generateCertHandler)))
	http.Handle("/x/markdownpreview/", gz.GzipHandler(logReq(markdownPreview)))
	http.Handle("/x/mergerequest/", gz.GzipHandler(logReq(mergeRequestHandler)))
	http.Handle("/x/savesettings", gz.GzipHandler(logReq(saveSettingsHandler)))
	http.Handle("/x/setdefaultbranch/", gz.GzipHandler(logReq(setDefaultBranchHandler)))
	http.Handle("/x/star/", gz.GzipHandler(logReq(starToggleHandler)))
	http.Handle("/x/table/", gz.GzipHandler(logReq(tableViewHandler)))
	http.Handle("/x/tablenames/", gz.GzipHandler(logReq(tableNamesHandler)))
	http.Handle("/x/updatebranch/", gz.GzipHandler(logReq(updateBranchHandler)))
	http.Handle("/x/updatecomment/", gz.GzipHandler(logReq(updateCommentHandler)))
	http.Handle("/x/updatediscuss/", gz.GzipHandler(logReq(updateDiscussHandler)))
	http.Handle("/x/updaterelease/", gz.GzipHandler(logReq(updateReleaseHandler)))
	http.Handle("/x/updatetag/", gz.GzipHandler(logReq(updateTagHandler)))
	http.Handle("/x/uploaddata/", gz.GzipHandler(logReq(uploadDataHandler)))
	http.Handle("/x/visdel/", gz.GzipHandler(logReq(visDel)))
	http.Handle("/x/visdlresults/", gz.GzipHandler(logReq(visDownloadResults)))
	http.Handle("/x/visget/", gz.GzipHandler(logReq(visGet)))
	http.Handle("/x/vissave/", gz.GzipHandler(logReq(visSave)))
	http.Handle("/x/watch/", gz.GzipHandler(logReq(watchToggleHandler)))

	// Add routes which are only useful during testing
	if com.Conf.Environment.Environment == "test" {
		http.Handle("/x/test/seed", gz.GzipHandler(logReq(com.CypressSeed)))
		http.Handle("/x/test/envprod", gz.GzipHandler(logReq(com.EnvProd)))
		http.Handle("/x/test/envtest", gz.GzipHandler(logReq(com.EnvTest)))
		http.Handle("/x/test/switchdefault", gz.GzipHandler(logReq(com.SwitchDefault)))
		http.Handle("/x/test/switchfirst", gz.GzipHandler(logReq(com.SwitchFirst)))
		http.Handle("/x/test/switchsecond", gz.GzipHandler(logReq(com.SwitchSecond)))
		http.Handle("/x/test/switchthird", gz.GzipHandler(logReq(com.SwitchThird)))
		http.Handle("/x/test/logout", gz.GzipHandler(logReq(com.TestLogout)))
	}

	// CSS
	http.Handle("/css/bootstrap-3.3.7.min.css", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "css", "bootstrap-3.3.7.min.css"))
	})))
	http.Handle("/css/bootstrap.min.css.map", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "css", "bootstrap-3.3.7.min.css.map"))
	})))
	http.Handle("/css/font-awesome-4.7.0.min.css", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "css", "font-awesome-4.7.0.min.css"))
	})))
	http.Handle("/css/local.css", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "css", "local.css"))
	})))

	// Fonts
	http.Handle("/css/FontAwesome.otf", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "fonts", "FontAwesome-4.7.0.otf"))
	})))
	http.Handle("/css/fontawesome-webfont.eot", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "fonts", "fontawesome-webfont-4.7.0.eot"))
	})))
	http.Handle("/css/fontawesome-webfont.svg", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "fonts", "fontawesome-webfont-4.7.0.svg"))
	})))
	http.Handle("/css/fontawesome-webfont.ttf", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "fonts", "fontawesome-webfont-4.7.0.ttf"))
	})))
	http.Handle("/css/fontawesome-webfont.woff", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "fonts", "fontawesome-webfont-4.7.0.woff"))
	})))
	http.Handle("/css/fontawesome-webfont.woff2", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "fonts", "fontawesome-webfont-4.7.0.woff2"))
	})))
	http.Handle("/fonts/glyphicons-halflings-regular.eot", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "fonts", "glyphicons-halflings-regular.eot"))
	})))
	http.Handle("/fonts/glyphicons-halflings-regular.svg", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "fonts", "glyphicons-halflings-regular.svg"))
	})))
	http.Handle("/fonts/glyphicons-halflings-regular.ttf", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "fonts", "glyphicons-halflings-regular.ttf"))
	})))
	http.Handle("/fonts/glyphicons-halflings-regular.woff", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "fonts", "glyphicons-halflings-regular.woff"))
	})))
	http.Handle("/fonts/glyphicons-halflings-regular.woff2", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "fonts", "glyphicons-halflings-regular.woff2"))
	})))

	// Javascript
	http.Handle("/js/angular-1.8.2.min.js", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "js", "angular-1.8.2.min.js"))
	})))
	http.Handle("/js/angular.min.js.map", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "js", "angular-1.8.2.min.js.map"))
	})))
	http.Handle("/js/angular-sanitize-1.8.2.min.js", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "js", "angular-sanitize-1.8.2.min.js"))
	})))
	http.Handle("/js/angular-sanitize.min.js.map", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "js", "angular-sanitize-1.8.2.min.js.map"))
	})))

	http.Handle("/js/dbhub.js", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "js", "dbhub.js"))
	})))

	http.Handle("/js/local.js", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "js", "local.js"))
	})))

	http.Handle("/js/plotly-basic-2.18.2.min.js", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "js", "plotly-basic-2.18.2.min.js"))
	})))

	http.Handle("/js/ui-bootstrap-tpls-2.5.0.min.js", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "js", "ui-bootstrap-tpls-2.5.0.min.js"))
	})))

	// Other static files
	http.Handle("/images/auth0.svg", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "auth0.svg"))
	})))
	http.Handle("/images/digitalocean.svg", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "digitalocean.svg"))
	})))
	http.Handle("/images/sqlitebrowser.svg", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "sqlitebrowser.svg"))
	})))
	http.Handle("/favicon.ico", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "favicon.ico"))
	})))
	http.Handle("/robots.txt", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "robots.txt"))
	})))

	// Landing page images
	http.Handle("/images/db4s_screenshot1.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "db4s_screenshot1.png"))
	})))
	http.Handle("/images/db4s_screenshot1-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "db4s_screenshot1-50px.png"))
	})))
	http.Handle("/images/db4s_screenshot2.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "db4s_screenshot2.png"))
	})))
	http.Handle("/images/db4s_screenshot2-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "db4s_screenshot2-50px.png"))
	})))
	http.Handle("/images/db4s_screenshot3.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "db4s_screenshot3.png"))
	})))
	http.Handle("/images/db4s_screenshot3-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "db4s_screenshot3-50px.png"))
	})))
	http.Handle("/images/db4s_screenshot4.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "db4s_screenshot4.png"))
	})))
	http.Handle("/images/db4s_screenshot4-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "db4s_screenshot4-50px.png"))
	})))
	http.Handle("/images/pub_priv1.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "pub_priv1.png"))
	})))
	http.Handle("/images/pub_priv1-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "pub_priv1-50px.png"))
	})))
	http.Handle("/images/watch1.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "watch1.png"))
	})))
	http.Handle("/images/watch1-46px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "watch1-46px.png"))
	})))
	http.Handle("/images/discussions1.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "discussions1.png"))
	})))
	http.Handle("/images/discussions1-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "discussions1-50px.png"))
	})))
	http.Handle("/images/discussions2.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "discussions2.png"))
	})))
	http.Handle("/images/discussions2-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "discussions2-50px.png"))
	})))
	http.Handle("/images/discussions3.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "discussions3.png"))
	})))
	http.Handle("/images/discussions3-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "discussions3-50px.png"))
	})))
	http.Handle("/images/version_control_history1.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "version_control_history1.png"))
	})))
	http.Handle("/images/version_control_history1-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "version_control_history1-50px.png"))
	})))
	http.Handle("/images/version_control_history2.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "version_control_history2.png"))
	})))
	http.Handle("/images/version_control_history2-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "version_control_history2-50px.png"))
	})))
	http.Handle("/images/merge1.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "merge1.png"))
	})))
	http.Handle("/images/merge1-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "merge1-50px.png"))
	})))
	http.Handle("/images/merge2.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "merge2.png"))
	})))
	http.Handle("/images/merge2-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "merge2-50px.png"))
	})))
	http.Handle("/images/merge3.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "merge3.png"))
	})))
	http.Handle("/images/merge3-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "merge3-50px.png"))
	})))
	http.Handle("/images/merge4.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "merge4.png"))
	})))
	http.Handle("/images/merge4-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "merge4-50px.png"))
	})))
	http.Handle("/images/plotly1.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "plotly1.png"))
	})))
	http.Handle("/images/plotly1-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "plotly1-50px.png"))
	})))
	http.Handle("/images/plotly2.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "plotly2.png"))
	})))
	http.Handle("/images/plotly2-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "plotly2-50px.png"))
	})))
	http.Handle("/images/plotly3.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "plotly3.png"))
	})))
	http.Handle("/images/plotly3-50px.png", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "plotly3-50px.png"))
	})))
	http.Handle("/images/dbhub-vis-720.mp4", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "dbhub-vis-720.mp4"))
	})))
	http.Handle("/images/dbhub-vis-720.webm", gz.GzipHandler(logReq(func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filepath.Join(com.Conf.Web.BaseDir, "webui", "images", "dbhub-vis-720.webm"))
	})))

	// Start webUI server
	log.Printf("WebUI server starting on https://%s\n", com.Conf.Web.ServerName)
	srv := &http.Server{
		Addr: com.Conf.Web.BindAddress,
		TLSConfig: &tls.Config{
			MinVersion: tls.VersionTLS12, // TLS 1.2 is now the lowest acceptable level
		},
	}
	err = srv.ListenAndServeTLS(com.Conf.Web.Certificate, com.Conf.Web.CertificateKey)

	// Shut down nicely
	com.DisconnectPostgreSQL()
	if err != nil {
		log.Println(err)
	}

	err = com.CloseMQChannel(com.AmqpChan)
	if err != nil {
		log.Fatal(err)
	}
}

func mainHandler(w http.ResponseWriter, r *http.Request) {
	// Split the request URL into path components
	pathStrings := strings.Split(r.URL.Path, "/")

	// numPieces will be 2 if the request was for the root directory (https://server/), or if
	// the request included only a single path component (https://server/someuser) and no trailing slash
	var dbName, userName string
	numPieces := len(pathStrings)
	switch numPieces {
	case 2:
		userName = pathStrings[1]
		// Check if the request was for the root directory
		if pathStrings[1] == "" {
			// Yep, root directory request
			frontPage(w, r)
			return
		}

		// The request was for a user page
		userPage(w, r, userName)
		return
	case 3:
		userName = pathStrings[1]
		dbName = pathStrings[2]

		// This catches the case where a "/" is on the end of a user page URL
		if dbName == "" {
			// The request was for a user page
			userPage(w, r, userName)
			return
		}
	default:
		// TODO: Add support for folders and sub folders
		// TODO  eg: Allow for collections of databases
		// TODO    * /user/collectionFoo/database1
		// TODO    * /user/collectionFoo/database2
		// TODO    * /user/collectionBar/database1
		// TODO    * /user/collectionBar/database2

		// We haven't yet added support for folders and subfolders, so bounce back to the /user/database page
		http.Redirect(w, r, fmt.Sprintf("/%s/%s", pathStrings[1], pathStrings[2]), http.StatusTemporaryRedirect)
		return
	}

	userName = pathStrings[1]
	dbName = pathStrings[2]

	// Validate the user supplied user and database name
	err := com.ValidateUserDB(userName, dbName)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Invalid user or database name")
		return
	}

	// TODO: Add support for folders and sub-folders in request paths
	dbFolder := "/"

	// A specific database was requested
	databasePage(w, r, userName, dbFolder, dbName)
}

// Returns HTML rendered content from a given markdown string, for the settings page README preview tab.
func markdownPreview(w http.ResponseWriter, r *http.Request) {
	// Extract and unescape the markdown text form value
	a := r.PostFormValue("mkdown")
	mkDown, err := url.QueryUnescape(a)
	if err != nil {
		fmt.Fprint(w, "Something went wrong when unescaping provided value")
		return
	}

	// Validate the markdown source provided, just to be safe
	var renderedText []byte
	if mkDown != "" {
		err := com.Validate.Var(mkDown, "markdownsource")
		if err != nil {
			fmt.Fprint(w, "Invalid characters in Markdown")
			return
		}
		renderedText = gfm.Markdown([]byte(mkDown))
	}

	// Send the rendered version back to the caller
	fmt.Fprint(w, string(renderedText))
}

// Handler which does merging to MR's.  Called from the MR details page
func mergeRequestHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		fmt.Fprint(w, "You need to be logged in")
		return
	}

	// Extract and validate the form variables
	dbOwner, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Missing or incorrect data supplied")
		return
	}

	// Ensure an MR id was given
	a := r.PostFormValue("mrid")
	if a == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Missing merge request id")
		return
	}
	mrID, err := strconv.Atoi(a)
	if err != nil {
		log.Printf("Error converting string '%s' to integer in function '%s': %s\n", com.SanitiseLogString(a),
			com.GetCurrentFunctionName(), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Error when parsing merge request id value")
		return
	}

	// Check if the requested database exists
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	if !exists {
		w.WriteHeader(http.StatusNotFound)
		fmt.Fprintf(w, "Database '%s%s%s' doesn't exist", dbOwner, dbFolder, dbName)
		return
	}

	// Retrieve the names of the source & destination databases and branches
	disc, err := com.Discussions(dbOwner, dbFolder, dbName, com.MERGE_REQUEST, mrID)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	branchName := disc[0].MRDetails.DestBranch
	commitDiffList := disc[0].MRDetails.Commits
	srcOwner := disc[0].MRDetails.SourceOwner
	srcFolder := disc[0].MRDetails.SourceFolder
	srcDBName := disc[0].MRDetails.SourceDBName
	srcBranchName := disc[0].MRDetails.SourceBranch

	// Ensure the merge request isn't closed
	if !disc[0].Open {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Cannot merge a closed merge request")
		return
	}

	// * The required details have been collected, and sanity checks completed, so merge the MR *

	message := fmt.Sprintf("Merge branch '%s' of '%s%s%s' into '%s'", srcBranchName, srcOwner, srcFolder,
		srcDBName, branchName)
	_, err = com.Merge(dbOwner, dbFolder, dbName, branchName, srcOwner, srcFolder, srcDBName, commitDiffList, message, loggedInUser)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}

	// Change the status of the MR to closed, and indicate it was successfully merged
	err = com.StoreComment(dbOwner, dbFolder, dbName, loggedInUser, mrID, "", true,
		com.CLOSED_WITH_MERGE)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}

	// Invalidate the memcached entries for the destination database case
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Send a success message back to the caller
	w.WriteHeader(http.StatusOK)
}

// This handles incoming requests for the preferences page by logged in users.
func prefHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Preferences handler"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		errorPage(w, r, http.StatusUnauthorized, "You need to be logged in")
		return
	}

	// Gather submitted form data (if any)
	maxRows := r.PostFormValue("maxrows")
	displayName := r.PostFormValue("fullname")
	email := r.PostFormValue("email")

	// If no form data was submitted, display the preferences page form
	if maxRows == "" {
		prefPage(w, r, fmt.Sprintf("%s", loggedInUser))
		return
	}

	// Basic sanity check
	if displayName == "" {
		errorPage(w, r, http.StatusBadRequest, "Full name can't be blank!")
		return
	}
	if email == "" {
		errorPage(w, r, http.StatusBadRequest, "Email address can't be blank!")
		return
	}

	// Validate submitted form data
	err = com.Validate.Var(maxRows, "required,numeric,min=1,max=500")
	if err != nil {
		log.Printf("%s: Maximum rows value failed validation: %s\n", pageName, err)
		errorPage(w, r, http.StatusBadRequest, "Error when parsing maximum rows preference value")
		return
	}
	maxRowsNum, err := strconv.Atoi(maxRows)
	if err != nil {
		log.Printf("%s: Error converting string '%v' to integer: %s\n", pageName, com.SanitiseLogString(maxRows), err)
		errorPage(w, r, http.StatusBadRequest, "Error when parsing preference data")
		return
	}
	err = com.ValidateDisplayName(displayName)
	if err != nil {
		log.Printf("%s: Display name '%s' failed validation: %s\n", pageName, com.SanitiseLogString(displayName), err)
		errorPage(w, r, http.StatusBadRequest, "Error when parsing full name value")
		return
	}
	err = com.Validate.Var(email, "required,email")
	if err != nil {
		// Check for the special case of username@server, which may fail standard email validation checks
		// eg username@localhost, won't validate as an email address, but should be accepted anyway
		serverName := strings.Split(com.Conf.Web.ServerName, ":")
		em := fmt.Sprintf("%s@%s", loggedInUser, serverName[0])
		if email != em {
			log.Printf("%s: Email value failed validation: %s\n", pageName, err)
			errorPage(w, r, http.StatusBadRequest, "Error when parsing email value")
			return
		}
	}

	// Make sure the email address isn't already assigned to a different user
	a, _, err := com.GetUsernameFromEmail(email)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, "Error when checking email address")
		return
	}
	if a != "" && strings.ToLower(a) != strings.ToLower(loggedInUser) {
		errorPage(w, r, http.StatusBadRequest, "That email address is already associated with a different user")
		return
	}

	// TODO: Store previous email addresses in a database table that associates them with the username.  This will be
	// TODO  needed so looking up an old email finds the correct username.  For example when looking through historical
	// TODO  commit data

	// Update the preference data in the database
	err = com.SetUserPreferences(loggedInUser, maxRowsNum, displayName, email)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, "Error when updating preferences")
		return
	}

	// Bounce to the user home page
	http.Redirect(w, r, "/"+loggedInUser, http.StatusSeeOther)
}

// Handler for the Database Settings page
func saveSettingsHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		errorPage(w, r, http.StatusUnauthorized, "You need to be logged in")
		return
	}

	// Extract the username, folder, and (current) database name form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, err.Error())
		return
	}
	dbOwner := strings.ToLower(usr)

	// Default to the root folder if none was given
	if dbFolder == "" {
		dbFolder = "/"
	}

	// Make sure a username was given
	if len(dbOwner) == 0 || dbOwner == "" {
		// No username supplied
		errorPage(w, r, http.StatusBadRequest, "No username supplied!")
		return
	}

	// Make sure the database owner matches the logged in user
	if strings.ToLower(loggedInUser) != strings.ToLower(dbOwner) {
		errorPage(w, r, http.StatusBadRequest, "You can only change settings for your own databases.")
		return
	}

	// Extract the form variables
	oneLineDesc := r.PostFormValue("onelinedesc")
	newName := r.PostFormValue("newname")
	fullDesc := r.PostFormValue("fulldesc")
	defTable := r.PostFormValue("defaulttable") // TODO: Update the default table to be "per branch"
	licences := r.PostFormValue("licences")
	sharesRaw := r.PostFormValue("shares")

	// Validate the licence names
	branchLics := make(map[string]string)
	err = json.Unmarshal([]byte(licences), &branchLics)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	for bName, lName := range branchLics {
		err = com.ValidateLicence(lName)
		if err != nil {
			errorPage(w, r, http.StatusBadRequest, fmt.Sprintf(
				"Validation failed on licence name for branch '%s'", bName))
			return
		}
	}

	// Validate the share information
	// TODO - Probably need to add some logic here so that the user submitting the change can't
	//        make changes for themselves
	shares := make(map[string]com.ShareDatabasePermissions)
	err = json.Unmarshal([]byte(sharesRaw), &shares)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	for user, access := range shares {
		exists, err := com.CheckUserExists(user)
		if exists == false || err != nil || (access != com.MayRead && access != com.MayReadAndWrite) {
			errorPage(w, r, http.StatusBadRequest, fmt.Sprintf(
				"Validation failed for user '%s'", user))
			return
		}
	}

	// Validate the source URL
	sourceURL, err := com.GetFormSourceURL(r)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Validation failed for source URL value")
		return
	}

	// Grab and validate the supplied default branch name
	defBranch, err := com.GetFormBranch(r)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Validation failed for branch name")
		return
	}

	// Grab and validate the supplied "public" form field
	public, err := com.GetPub(r)
	if err != nil {
		log.Printf("Error when converting public value to boolean: %v\n", err)
		errorPage(w, r, http.StatusBadRequest, "Public value incorrect")
		return
	}

	// If set, validate the new database name
	if newName != dbName {
		err := com.ValidateDB(newName)
		if err != nil {
			log.Printf("Validation failed for new database name '%s': %s", com.SanitiseLogString(newName), err)
			errorPage(w, r, http.StatusBadRequest, "New database name failed validation")
			return
		}
	}

	// Validate characters and length of the one line description
	if oneLineDesc != "" {
		err = com.Validate.Var(oneLineDesc, "markdownsource,max=120")
		if err != nil {
			log.Printf("One line description '%s' failed validation", com.SanitiseLogString(oneLineDesc))
			errorPage(w, r, http.StatusBadRequest, "One line description failed validation")
			return
		}
	}

	// Validate the full description
	if fullDesc != "" {
		err = com.Validate.Var(fullDesc, "markdownsource,max=8192") // 8192 seems reasonable.  Maybe too long?
		if err != nil {
			log.Printf("Full description '%s' failed validation", com.SanitiseLogString(fullDesc))
			errorPage(w, r, http.StatusBadRequest, "Full description failed validation")
			return
		}
	}

	// Validate the name of the default table
	err = com.ValidatePGTable(defTable)
	if err != nil {
		// Validation failed
		log.Printf("Validation failed for name of default table '%s': %s", com.SanitiseLogString(defTable), err)
		errorPage(w, r, http.StatusBadRequest, "Validation failed for name of default table")
		return
	}

	// Get the list of branches in the database
	branchList, err := com.GetBranches(dbOwner, dbFolder, dbName)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Retrieve the SHA256 for the database file
	head, ok := branchList[defBranch]
	if !ok {
		errorPage(w, r, http.StatusInternalServerError, "Requested branch name not found")
		return
	}
	bkt, id, _, err := com.MinioLocation(dbOwner, dbFolder, dbName, head.Commit, loggedInUser)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Get a handle from Minio for the database object
	sdb, err := com.OpenSQLiteDatabase(bkt, id)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Automatically close the SQLite database when this function finishes
	defer sdb.Close()

	// Retrieve the list of tables in the database
	// TODO: Update this to handle having a default table "per branch".  Even though it would mean looping here, it
	// TODO  seems like the only way to be flexible and accurate enough for our purposes
	tables, err := com.TablesAndViews(sdb, fmt.Sprintf("%s%s%s", dbOwner, dbFolder, dbName))
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// If a specific table was requested, check that it's present
	if defTable != "" {
		// Check the requested table is present
		tablePresent := false
		for _, tbl := range tables {
			if tbl == defTable {
				tablePresent = true
			}
		}
		if tablePresent == false {
			// The requested table doesn't exist in the database
			log.Printf("Requested table '%s' not present in database '%s%s%s'\n",
				com.SanitiseLogString(defTable), com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName))
			errorPage(w, r, http.StatusBadRequest, "Requested table not present")
			return
		}
	}

	// Grab the complete commit list for the database
	commitList, err := com.GetCommitList(dbOwner, dbFolder, dbName)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Loop through the branches of the database, processing the user submitted licence choice for each
	branchesUpdated := false
	newBranchHeads := make(map[string]com.BranchEntry)
	for bName, bEntry := range branchList {
		// Get the previous licence entry for the branch
		c, ok := commitList[bEntry.Commit]
		if !ok {
			errorPage(w, r, http.StatusInternalServerError, fmt.Sprintf(
				"Error when retrieving commit ID '%s', branch '%s' for database '%s%s%s'", bEntry.Commit,
				bName, dbOwner, dbFolder, dbName))
			return
		}
		dbEntry := c.Tree.Entries[0]
		licSHA := dbEntry.LicenceSHA
		var oldLic string
		if licSHA != "" {
			oldLic, _, err = com.GetLicenceInfoFromSha256(loggedInUser, licSHA)
			if err != nil {
				errorPage(w, r, http.StatusInternalServerError, err.Error())
				return
			}
		}

		// Get the new licence entry for the branch
		newLic, ok := branchLics[bName]
		if !ok {
			errorPage(w, r, http.StatusInternalServerError, fmt.Sprintf(
				"Missing licence entry for branch '%s'", bName))
			return
		}

		// If the new licence given for a branch is different from the old one, generate a new commit, add it to the
		// commit list, and update the branch with it
		if oldLic != newLic {
			// Retrieve the SHA256 of the new licence
			newLicSHA, err := com.GetLicenceSha256FromName(loggedInUser, newLic)
			if err != nil {
				errorPage(w, r, http.StatusInternalServerError, err.Error())
				return
			}

			// Create a new dbTree entry for the database file
			var e com.DBTreeEntry
			e.EntryType = com.DATABASE
			e.LastModified = dbEntry.LastModified.UTC()
			e.LicenceSHA = newLicSHA
			e.Name = dbEntry.Name
			e.Sha256 = dbEntry.Sha256
			e.Size = dbEntry.Size

			// Create a new dbTree structure for the new database entry
			var t com.DBTree
			t.Entries = append(t.Entries, e)
			t.ID = com.CreateDBTreeID(t.Entries)

			// Retrieve the user details
			usr, err := com.User(loggedInUser)
			if err != nil {
				errorPage(w, r, http.StatusInternalServerError, "An error occurred when retrieving user details")
			}

			// Create a new commit for the new tree
			newCom := com.CommitEntry{
				CommitterName:  c.AuthorName,
				CommitterEmail: c.AuthorEmail,
				Message:        fmt.Sprintf("Licence changed from '%s' to '%s'.", oldLic, newLic),
				Parent:         bEntry.Commit,
				Timestamp:      time.Now().UTC(),
				Tree:           t,
			}
			newCom.AuthorName = usr.DisplayName
			newCom.AuthorEmail = usr.Email

			// Calculate the new commit ID, which incorporates the updated tree ID (and thus the new licence sha256)
			newCom.ID = com.CreateCommitID(newCom)

			// Add the new commit to the commit list
			commitList[newCom.ID] = newCom

			// Add the commit to the new branch heads list, and set a flag indicating it needs to be stored to the
			// database after the licence processing finishes
			newBranchEntry := com.BranchEntry{
				Commit:      newCom.ID,
				CommitCount: bEntry.CommitCount + 1,
				Description: bEntry.Description,
			}
			newBranchHeads[bName] = newBranchEntry
			branchesUpdated = true
		} else {
			// Copy the old branch entry to the new list
			newBranchHeads[bName] = branchList[bName]
		}
	}

	// If the branches were updated, store the new commit list and branch heads
	if branchesUpdated {
		err = com.StoreCommits(dbOwner, dbFolder, dbName, commitList)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}

		err = com.StoreBranches(dbOwner, dbFolder, dbName, newBranchHeads)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}
	}

	// Store the new share settings if they changed
	oldShares, err := com.GetShares(dbOwner, dbFolder, dbName)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	if reflect.DeepEqual(shares, oldShares) == false {
		err = com.StoreShares(dbOwner, dbFolder, dbName, shares)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}
	}

	// If the database doesn't have a 1-liner description, don't save the placeholder text as one
	if oneLineDesc == "No description" {
		oneLineDesc = ""
	}

	// Same thing, but for the full length description
	if fullDesc == "No full description" {
		fullDesc = ""
	}

	// Save settings
	err = com.SaveDBSettings(dbOwner, dbFolder, dbName, oneLineDesc, fullDesc, defTable, public, sourceURL, defBranch)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, err.Error())
		return
	}

	// If the new database name is different from the old one, perform the rename
	// Note - It's useful to do this *after* the SaveDBSettings() call, so the cache invalidation code at the
	// end of that function gets run and we don't have to repeat it here
	// TODO: We'll probably need to add support for renaming folders somehow too
	if newName != "" && newName != dbName {
		err = com.RenameDatabase(dbOwner, dbFolder, dbName, newName)
		if err != nil {
			errorPage(w, r, http.StatusBadRequest, err.Error())
			return
		}
	}

	// Settings saved, so bounce back to the database page
	http.Redirect(w, r, fmt.Sprintf("/%s%s%s", loggedInUser, dbFolder, newName), http.StatusSeeOther)
}

// This function sets a branch as the default for a given database.
func setDefaultBranchHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Set default branch handler"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbOwner := strings.ToLower(usr)

	// Check if a branch name was requested
	branchName, err := com.GetFormBranch(r)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// If any of the required values were empty, indicate failure
	if dbOwner == "" || dbFolder == "" || dbName == "" || branchName == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if !exists {
		log.Printf("%s: Validation failed for database name: %s", pageName, err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Make sure the database is owned by the logged in user. eg prevent changes to other people's databases
	if strings.ToLower(dbOwner) != strings.ToLower(loggedInUser) {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Load the existing branchHeads for the database
	branches, err := com.GetBranches(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Make sure the given branch exists
	if _, ok := branches[branchName]; !ok {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Set the default branch
	err = com.StoreDefaultBranchName(dbOwner, dbFolder, dbName, branchName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Invalidate the memcache data for the database, so the new default branch gets picked up
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Update succeeded
	w.WriteHeader(http.StatusOK)
}

// Handles JSON requests from the front end to toggle a database's star.
func starToggleHandler(w http.ResponseWriter, r *http.Request) {
	// Extract the user and database name
	// TODO: Add folder support
	dbOwner, dbName, err := com.GetOD(2, r) // 2 = Ignore "/x/star/" at the start of the URL
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		// No logged in username, so nothing to update
		// TODO: We should probably use a http status code instead of using -1
		fmt.Fprint(w, "-1") // -1 tells the front end not to update the displayed star count
		return
	}

	// Toggle on or off the starring of a database by a user
	err = com.ToggleDBStar(loggedInUser, dbOwner, "/", dbName)
	if err != nil {
		fmt.Fprint(w, "-1") // -1 tells the front end not to update the displayed star count
		return
	}

	// Invalidate the old memcached entry for the database
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, "/", dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Return the updated star count
	newStarCount, err := com.DBStars(dbOwner, "/", dbName)
	if err != nil {
		fmt.Fprint(w, "-1") // -1 tells the front end not to update the displayed star count
		return
	}
	fmt.Fprint(w, newStarCount)
}

// Returns the table and view names present in a specific database commit
func tableNamesHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbOwner := strings.ToLower(usr)

	// Make sure a branch name was provided
	branchName, err := com.GetFormBranch(r)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// If any of the required values were empty, indicate failure
	if dbOwner == "" || dbFolder == "" || dbName == "" || branchName == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, false)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if !exists {
		log.Printf("%s: Validation failed for database name: %s", com.GetCurrentFunctionName(), err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Load the existing branchHeads for the database
	branches, err := com.GetBranches(loggedInUser, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Make sure the given branch exists
	head, ok := branches[branchName]
	if !ok {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprintf(w, "Unknown branch name: '%s'", branchName)
		return
	}
	commitID := head.Commit

	// * Retrieve the table names for the given commit *

	// Retrieve the Minio bucket and id for the commit
	bkt, id, _, err := com.MinioLocation(dbOwner, dbFolder, dbName, commitID, loggedInUser)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Get a handle from Minio for the SQLite database object
	sdb, err := com.OpenSQLiteDatabase(bkt, id)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Automatically close the SQLite database when this function finishes
	defer sdb.Close()

	// Retrieve the list of tables in the database
	sTbls, err := com.TablesAndViews(sdb, fmt.Sprintf("%s%s%s", dbOwner, dbFolder, dbName))
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Validate the tables names
	var d struct {
		DefTbl string   `json:"default_table"`
		Tables []string `json:"tables"`
	}
	for _, t := range sTbls {
		err = com.ValidatePGTable(t)
		if err == nil {
			// Validation passed, so add the table to the list
			d.Tables = append(d.Tables, t)
		}
	}

	// If the branch name given is the default branch, check what the default table is set to for it and pass that
	// info back as the one to have auto-selected in the drop down
	defBranch, err := com.GetDefaultBranchName(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if defBranch == branchName {
		dt, err := com.GetDefaultTableName(dbOwner, dbFolder, dbName)
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			return
		}

		// If the default table name is in the new table list, then set it as the default in the returned info
		fnd := false
		for _, j := range d.Tables {
			if j == dt {
				fnd = true
			}
		}
		if fnd == true {
			d.DefTbl = dt
		} else {
			// The "database default" table name wasn't found in the table list, so we can't use it.  Instead, we choose
			// the first valid entry from the table list (if there is one)
			if len(d.Tables) > 0 {
				d.DefTbl = d.Tables[0]
			}
		}
	} else {
		// The requested branch isn't the database default, so pick the first first valid entry from the table list
		// (if there is one) and use that instead
		if len(d.Tables) > 0 {
			d.DefTbl = d.Tables[0]
		}
	}

	// JSON encode the result
	data, err := json.MarshalIndent(d, "", " ")
	if err != nil {
		log.Println(err)
		return
	}

	// TODO: It would probably be useful to store these table names in memcache too, to later retrieval

	// Return the table name info
	w.WriteHeader(http.StatusOK)
	fmt.Fprint(w, string(data))
}

// This passes table row data back to the main UI in JSON format.
func tableViewHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Table data handler"

	// Retrieve user, database, table, and commit ID
	// TODO: Add folder support
	dbOwner, dbName, requestedTable, commitID, err := com.GetODTC(2, r) // 1 = Ignore "/x/table/" at the start of the URL
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbFolder := "/"

	// Extract sort column, sort direction, and offset variables if present
	sortCol := r.FormValue("sort")
	sortDir := r.FormValue("dir")
	offsetStr := r.FormValue("offset")
	var rowOffset int
	if offsetStr == "" {
		rowOffset = 0
	} else {
		rowOffset, err = strconv.Atoi(offsetStr)
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}

		// Ensure the row offset isn't negative
		if rowOffset < 0 {
			rowOffset = 0
		}
	}

	// Sanity check the sort column name
	if sortCol != "" {
		// Validate the sort column text, as we use it in string smashing SQL queries so need to be even more
		// careful than usual
		err = com.ValidateFieldName(sortCol)
		if err != nil {
			log.Printf("Validation failed on requested sort field name '%v': %v\n", com.SanitiseLogString(sortCol),
				err.Error())
			w.WriteHeader(http.StatusBadRequest)
			return
		}
	}

	// If a sort direction was provided, validate it
	if sortDir != "" {
		if sortDir != "ASC" && sortDir != "DESC" {
			w.WriteHeader(http.StatusBadRequest)
			return
		}
	}

	// Retrieve session data (if any)
	loggedInUser, _, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Check if the user has access to the requested database
	bucket, id, _, err := com.MinioLocation(dbOwner, dbFolder, dbName, commitID, loggedInUser)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Sanity check
	if id == "" {
		// The requested database wasn't found
		log.Printf("%s: Requested database not found. Owner: '%s%s%s'", pageName, com.SanitiseLogString(dbOwner), dbFolder, com.SanitiseLogString(dbName))
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Determine the number of rows to display
	var maxRows int
	if loggedInUser != "" {
		// Retrieve the user preference data
		maxRows = com.PrefUserMaxRows(loggedInUser)
	} else {
		// Not logged in, so use the default number of display rows
		maxRows = com.DefaultNumDisplayRows
	}

	// If the data is available from memcached, use that instead of reading from the SQLite database itself
	dataCacheKey := com.TableRowsCacheKey(fmt.Sprintf("tablejson/%s/%s/%d", sortCol, sortDir, rowOffset),
		loggedInUser, dbOwner, dbFolder, dbName, commitID, requestedTable, maxRows)

	// If a cached version of the page data exists, use it
	var dataRows com.SQLiteRecordSet
	ok, err := com.GetCachedData(dataCacheKey, &dataRows)
	if err != nil {
		log.Printf("%s: Error retrieving table data from cache: %v\n", pageName, err)
	}
	if !ok {
		// * Data wasn't in cache, so we gather it from the SQLite database *

		// Open the Minio database
		sdb, err := com.OpenSQLiteDatabase(bucket, id)
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			return
		}

		// Automatically close the SQLite database when this function finishes
		defer sdb.Close()

		// Retrieve the list of tables in the database
		tables, err := sdb.Tables("")
		if err != nil {
			// An error occurred, so get the extended error code
			if cerr, ok := err.(sqlite.ConnError); ok {
				// Check if the error was due to the table being locked
				extCode := cerr.ExtendedCode()
				if extCode == 5 { // Magic number which (in this case) means "database is locked"
					// Wait 3 seconds then try again
					time.Sleep(3 * time.Second)
					tables, err = sdb.Tables("")
					if err != nil {
						log.Printf("Error retrieving table names: %s", err)
						return
					}
				} else {
					log.Printf("Error retrieving table names: %s", err)
					return
				}
			} else {
				log.Printf("Error retrieving table names: %s", err)
				return
			}
		}
		if len(tables) == 0 {
			// No table names were returned, so abort
			log.Printf("The database '%s' doesn't seem to have any tables. Aborting.", com.SanitiseLogString(dbName))
			return
		}
		vw, err := sdb.Views("")
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
		tables = append(tables, vw...)

		// If a specific table was requested, check it exists
		if requestedTable != "" {
			tablePresent := false
			for _, tableName := range tables {
				if requestedTable == tableName {
					tablePresent = true
				}
			}
			if tablePresent == false {
				// The requested table doesn't exist
				w.WriteHeader(http.StatusBadRequest)
				return
			}
		}

		// If no specific table was requested, use the first one
		if requestedTable == "" {
			requestedTable = tables[0]
		}

		// If a sort column was requested, verify it exists
		if sortCol != "" {
			colList, err := sdb.Columns("", requestedTable)
			if err != nil {
				log.Printf("Error when reading column names for table '%s': %v\n", com.SanitiseLogString(requestedTable),
					err.Error())
				w.WriteHeader(http.StatusInternalServerError)
				return
			}
			colExists := false
			for _, j := range colList {
				if j.Name == sortCol {
					colExists = true
				}
			}
			if colExists == false {
				// The requested sort column doesn't exist, so we fall back to no sorting
				sortCol = ""
			}
		}

		// Read the data from the database
		dataRows, err = com.ReadSQLiteDB(sdb, requestedTable, sortCol, sortDir, maxRows, rowOffset)
		if err != nil {
			// Some kind of error when reading the database data
			log.Printf("Error occurred when reading table data for '%s%s%s', commit '%s': %s\n", com.SanitiseLogString(dbOwner),
				dbFolder, com.SanitiseLogString(dbName), com.SanitiseLogString(commitID), err.Error())
			w.WriteHeader(http.StatusInternalServerError)
			return
		}

		// Count the total number of rows in the requested table
		dataRows.TotalRows, err = com.GetSQLiteRowCount(sdb, requestedTable)
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			return
		}

		// Cache the data in memcache
		err = com.CacheData(dataCacheKey, dataRows, com.Conf.Memcache.DefaultCacheTime)
		if err != nil {
			log.Printf("%s: Error when caching table data for '%s%s%s': %v\n", pageName, com.SanitiseLogString(dbOwner), dbFolder,
				com.SanitiseLogString(dbName), err)
		}
	}

	// Format the output.  Use json.MarshalIndent() for nicer looking output
	jsonResponse, err := json.MarshalIndent(dataRows, "", " ")
	if err != nil {
		log.Println(err)
		return
	}

	//w.Header().Set("Access-Control-Allow-Origin", "*")
	fmt.Fprintf(w, "%s", jsonResponse)
}

// This function processes branch rename and description updates.
func updateBranchHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Update Branch handler"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbOwner := strings.ToLower(usr)

	// Unescape, then validate the new branch name
	a := r.PostFormValue("newbranch")
	nb, err := url.QueryUnescape(a)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	err = com.ValidateBranchName(nb)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	newName := nb

	// Validate new branch description
	var newDesc string
	b := r.PostFormValue("newdesc") // Optional
	if b != "" {
		nd, err := url.QueryUnescape(b)
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		err = com.Validate.Var(nd, "markdownsource")
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		newDesc = nd
	}

	// Make sure a branch name was provided
	branchName, err := com.GetFormBranch(r)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// If any of the required values were empty, indicate failure
	if branchName == "" || dbFolder == "" || dbName == "" || dbOwner == "" || newName == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if !exists {
		log.Printf("%s: Validation failed for database name: %s", pageName, err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Load the existing branchHeads for the database
	branches, err := com.GetBranches(loggedInUser, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Make sure the given branch exists
	oldInfo, ok := branches[branchName]
	if !ok {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// If the branch being changed is the default branch, and it's being renamed, we need to update the default branch
	// entry in the database with the new branch name
	defBranch, err := com.GetDefaultBranchName(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if defBranch == branchName {
		// Update the default branch name for the database
		err = com.StoreDefaultBranchName(dbOwner, dbFolder, dbName, newName)
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
	}

	// Update the branch info
	delete(branches, branchName)
	branches[newName] = com.BranchEntry{
		Commit:      oldInfo.Commit,
		CommitCount: oldInfo.CommitCount,
		Description: newDesc,
	}
	err = com.StoreBranches(dbOwner, dbFolder, dbName, branches)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Invalidate the memcache data for the database, so the new branch name gets picked up
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		return
	}

	// Update succeeded
	w.WriteHeader(http.StatusOK)
}

// This function processes comment text updates.
func updateCommentHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Update Comment handler"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbOwner := strings.ToLower(usr)

	// Ensure a discussion ID was given
	a := r.PostFormValue("discid")
	if a == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Missing discussion id")
		return
	}
	discID, err := strconv.Atoi(a)
	if err != nil {
		log.Printf("Error converting string '%s' to integer in function '%s': %s\n", com.SanitiseLogString(a),
			com.GetCurrentFunctionName(), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Error when parsing discussion id value")
		return
	}

	// Ensure a comment ID was given
	b := r.PostFormValue("comid")
	if b == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Missing comment id")
		return
	}
	comID, err := strconv.Atoi(b)
	if err != nil {
		log.Printf("Error converting string '%s' to integer in function '%s': %s\n", com.SanitiseLogString(a),
			com.GetCurrentFunctionName(), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Error when parsing comment id value")
		return
	}

	// Unescape, then validate the new comment text
	var newTxt string
	c := r.PostFormValue("comtext")
	nt, err := url.QueryUnescape(c)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	if nt != "" {
		err = com.Validate.Var(nt, "markdownsource")
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		newTxt = nt
	}

	// If any of the required values were empty, indicate failure
	if dbOwner == "" || dbFolder == "" || dbName == "" || discID == 0 || comID == 0 || newTxt == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Required values missing!")
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, false) // We don't require write access since discussions are considered public
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if !exists {
		log.Printf("%s: Validation failed for database name: %s", pageName, err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Update the discussion text
	err = com.UpdateComment(dbOwner, dbFolder, dbName, loggedInUser, discID, comID, newTxt)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}

	// Update succeeded
	w.WriteHeader(http.StatusOK)
	fmt.Fprint(w, string(gfm.Markdown([]byte(newTxt))))
}

// This function processes discussion title and body text updates.
func updateDiscussHandler(w http.ResponseWriter, r *http.Request) {
	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Bad request")
		return
	}
	dbOwner := strings.ToLower(usr)

	// Ensure a discussion ID was given
	a := r.PostFormValue("discid")
	if a == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Missing discussion id")
		return
	}
	discID, err := strconv.Atoi(a)
	if err != nil {
		log.Printf("Error converting string '%s' to integer in function '%s': %s\n", com.SanitiseLogString(a),
			com.GetCurrentFunctionName(), err)
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Error when parsing discussion id value")
		return
	}

	// Unescape, then validate the new discussion text
	var newTxt string
	b := r.PostFormValue("disctext")
	nt, err := url.QueryUnescape(b)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}
	if nt != "" {
		err = com.Validate.Var(nt, "markdownsource")
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			fmt.Fprint(w, "Discussion text failed validation")
			return
		}
		newTxt = nt
	}

	// Unescape, then validate the new discussion title
	var newTitle string
	c := r.PostFormValue("disctitle")
	ti, err := url.QueryUnescape(c)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, err.Error())
		return
	}
	if ti != "" {
		err = com.Validate.Var(ti, "discussiontitle,max=120")
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			fmt.Fprint(w, "Discussion title failed validation")
			return
		}
		newTitle = ti
	}

	// If any of the required values were empty, indicate failure
	if dbOwner == "" || dbFolder == "" || dbName == "" || discID == 0 || newTitle == "" || newTxt == "" {
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprint(w, "Required values missing!")
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, false) // We don't require write access since MRs are considered public
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	if !exists {
		w.WriteHeader(http.StatusNotFound)
		fmt.Fprint(w, "Database not found")
		return
	}

	// Update the discussion text
	err = com.UpdateDiscussion(dbOwner, dbFolder, dbName, loggedInUser, discID, newTitle, newTxt)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}

	// Update succeeded
	w.WriteHeader(http.StatusOK)
	fmt.Fprint(w, string(gfm.Markdown([]byte(newTxt))))
}

// This function processes release rename and description updates.
func updateReleaseHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Update Release handler"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbOwner := strings.ToLower(usr)

	// Validate new release name
	a := r.PostFormValue("newrel")
	nr, err := url.QueryUnescape(a)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	err = com.ValidateBranchName(nr)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	newName := nr

	// Validate new release description
	var newDesc string
	b := r.PostFormValue("newmsg") // Optional
	if b != "" {
		nd, err := url.QueryUnescape(b)
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		err = com.Validate.Var(nd, "markdownsource")
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		newDesc = nd
	}

	// Ensure a release name was supplied
	relName, err := com.GetFormRelease(r)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// If any of the required values were empty, indicate failure
	if relName == "" || dbFolder == "" || dbName == "" || dbOwner == "" || newName == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if !exists {
		log.Printf("%s: Validation failed for database name: %s", pageName, err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Load the existing releases for the database
	releases, err := com.GetReleases(loggedInUser, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Make sure the given release exists
	oldInfo, ok := releases[relName]
	if !ok {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Update the release info
	delete(releases, relName)
	releases[newName] = com.ReleaseEntry{
		Commit:        oldInfo.Commit,
		Date:          oldInfo.Date,
		Description:   newDesc,
		ReleaserEmail: oldInfo.ReleaserEmail,
		ReleaserName:  oldInfo.ReleaserName,
		Size:          oldInfo.Size,
	}

	err = com.StoreReleases(dbOwner, dbFolder, dbName, releases)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Update succeeded
	w.WriteHeader(http.StatusOK)
}

// This function processes tag rename and description updates.
func updateTagHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Update Tag handler"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	// Extract the required form variables
	usr, dbFolder, dbName, err := com.GetUFD(r, false)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbOwner := strings.ToLower(usr)

	// Validate new tag name
	a := r.PostFormValue("newtag")
	nt, err := url.QueryUnescape(a)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	err = com.ValidateBranchName(nt)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	newName := nt

	// If given, validate new tag description
	var newMsg string
	b := r.PostFormValue("newmsg") // Optional
	if b != "" {
		nm, err := url.QueryUnescape(b)
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		err = com.Validate.Var(nm, "markdownsource")
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		newMsg = nm
	}

	// Ensure a tag name was supplied
	tagName, err := com.GetFormTag(r)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// If any of the required values were empty, indicate failure
	if tagName == "" || dbFolder == "" || dbName == "" || dbOwner == "" || newName == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Make sure the database exists in the system
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != err {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	if !exists {
		log.Printf("%s: Validation failed for database name: %s", pageName, err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	// Load the existing tags for the database
	tags, err := com.GetTags(loggedInUser, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Make sure the given tag exists
	oldInfo, ok := tags[tagName]
	if !ok {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Update the tag info
	delete(tags, tagName)
	tags[newName] = com.TagEntry{
		Commit:      oldInfo.Commit,
		Date:        oldInfo.Date,
		Description: newMsg,
		TaggerEmail: oldInfo.TaggerEmail,
		TaggerName:  oldInfo.TaggerName,
	}

	err = com.StoreTags(dbOwner, dbFolder, dbName, tags)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Update succeeded
	w.WriteHeader(http.StatusOK)
}

// This function processes new database data submitted through the upload form.
func uploadDataHandler(w http.ResponseWriter, r *http.Request) {
	pageName := "Upload DB handler"

	// TODO: Investigate getting the last modified timestamp of the database file selected for upload
	// TODO   * https://developer.mozilla.org/en-US/docs/Web/API/File/lastModified

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		errorPage(w, r, http.StatusUnauthorized, "You need to be logged in")
		return
	}

	// Set the maximum accepted database size for uploading
	oversizeAllowed := false
	for _, user := range com.Conf.UserMgmt.SizeOverrideUsers {
		if loggedInUser == user {
			oversizeAllowed = true
		}
	}
	if !oversizeAllowed {
		r.Body = http.MaxBytesReader(w, r.Body, com.MaxDatabaseSize*1024*1024)

		// Check whether the uploaded database is too large (except for specific users)
		if r.ContentLength > (com.MaxDatabaseSize * 1024 * 1024) {
			errorPage(w, r, http.StatusBadRequest,
				fmt.Sprintf("Database is too large. Maximum database upload size is %d MB, yours is %d MB",
					com.MaxDatabaseSize, r.ContentLength/1024/1024))
			log.Println(fmt.Sprintf("'%s' attempted to upload an oversized database %d MB in size.  Limit is %d MB\n",
				loggedInUser, r.ContentLength/1024/1024, com.MaxDatabaseSize))
			return
		}
	}

	// Prepare the form data
	err = r.ParseMultipartForm(32 << 21) // 128MB of ram max
	if err != nil {
		log.Printf(err.Error())
		errorPage(w, r, http.StatusBadRequest, err.Error())
		return
	}
	if err = r.ParseForm(); err != nil {
		log.Printf("%s: ParseForm() error: %v\n", pageName, err)
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Grab and validate the supplied "public" form field
	var accessType com.SetAccessType
	var public bool
	public, err = com.GetPub(r)
	if err != nil {
		log.Printf("%s: Error when converting public value to boolean: %v\n", pageName, err)
		errorPage(w, r, http.StatusBadRequest, fmt.Sprintf("Public value '%v' incorrect", html.EscapeString(r.PostFormValue("public"))))
		return
	}
	if public {
		accessType = com.SetToPublic
	} else {
		accessType = com.SetToPrivate
	}

	// Grab and validate the supplied "live" form field
	var isLiveDB bool
	isLiveDB, err = com.GetFormLive(r)
	if err != nil {
		log.Printf("%s: Error when converting live value to boolean: %v\n", pageName, err)
		errorPage(w, r, http.StatusBadRequest, fmt.Sprintf("Live value '%v' incorrect", html.EscapeString(r.PostFormValue("live"))))
		return
	}

	// Validate the licence value
	licenceName, err := com.GetFormLicence(r)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Validation failed for licence value")
		return
	}

	// Validate the source URL
	sourceURL, err := com.GetFormSourceURL(r)
	if err != nil {
		errorPage(w, r, http.StatusBadRequest, "Validation failed for source URL value")
		return
	}

	// Validate the commit message
	var commitMsg string
	cm := r.PostFormValue("commitmsg")
	if cm != "" {
		err = com.ValidateMarkdown(cm)
		if err != nil {
			errorPage(w, r, http.StatusBadRequest, "Validation failed for the commit message")
			return
		}
		commitMsg = cm
	}

	// Validate the (optional) branch name
	branchName, err := com.GetFormBranch(r)
	if err != nil {
		log.Printf("%s: Error when validating branch name '%s': %v\n", pageName, com.SanitiseLogString(branchName), err)
		errorPage(w, r, http.StatusBadRequest, "Branch name value failed validation")
		return
	}

	// TODO: Add support for folders and sub-folders
	var dbOwner, dbName string
	dbFolder := "/"

	tempFile, handler, err := r.FormFile("database")
	if err != nil {
		log.Printf("%s: Uploading file failed: %v\n", pageName, err)
		errorPage(w, r, http.StatusInternalServerError, "Database file missing from upload data?")
		return
	}
	dbName = handler.Filename
	defer tempFile.Close()

	// If a database owner and name was passed in separately, we use that instead of the filename
	{
		usr, _, db, err := com.GetUFD(r, true)
		if err != nil {
			if db != "" {
				errorPage(w, r, http.StatusInternalServerError, "Something seems to be wrong with the owner name or database name")
			}
		}
		if usr != "" || db != "" {
			dbOwner = usr
			dbName = db
		}
	}
	if dbOwner == "" {
		dbOwner = loggedInUser
	}

	// Validate the database name
	err = com.ValidateDB(dbName)
	if err != nil {
		log.Printf("%s: Validation failed for database name: %s", pageName, err)
		errorPage(w, r, http.StatusBadRequest, "Invalid database name")
		return
	}

	// Check if the requested database exists already
	exists, err := com.CheckDBPermissions(loggedInUser, dbOwner, dbFolder, dbName, true)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Was a user agent part of the request?
	var userAgent string
	ua, ok := r.Header["User-Agent"]
	if ok {
		userAgent = ua[0]
	}

	// If this is supposed to be a live database, and the database already exists, error out
	if isLiveDB && exists {
		errorPage(w, r, http.StatusConflict, "Can't upload a live database over the top of an existing one of the same name.  If you really want to do that, then delete the old one first")
		return
	}

	// Retrieve the commit ID for the head of the specified branch
	var commitID, sha string
	var numBytes int64
	createBranch := false
	if !isLiveDB {
		if exists {
			branchList, err := com.GetBranches(dbOwner, dbFolder, dbName)
			if err != nil {
				http.Error(w, err.Error(), http.StatusInternalServerError)
				errorPage(w, r, http.StatusInternalServerError, err.Error())
				return
			}
			branchEntry, ok := branchList[branchName]
			if !ok {
				// The specified branch name doesn't exist, so we'll need to create it
				createBranch = true

				// We also need a commit ID to branch from, so we use the head commit of the default branch
				defBranch, err := com.GetDefaultBranchName(dbOwner, dbFolder, dbName)
				if err != nil {
					errorPage(w, r, http.StatusInternalServerError, err.Error())
					return
				}
				branchEntry, ok = branchList[defBranch]
				if !ok {
					errorPage(w, r, http.StatusInternalServerError, "Could not retrieve commit info for default branch entry")
					return
				}
			}
			commitID = branchEntry.Commit
		}

		// Sanity check the uploaded database, and if ok then add it to the system
		numBytes, _, sha, err = com.AddDatabase(loggedInUser, dbOwner, dbFolder, dbName, createBranch, branchName,
			commitID, accessType, licenceName, commitMsg, sourceURL, tempFile, time.Now(), time.Time{},
			"", "", "", "", nil, "")
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}

		// Make a record of the upload
		err = com.LogUpload(dbOwner, dbFolder, dbName, loggedInUser, r.RemoteAddr, "webui", userAgent, time.Now().UTC(), sha)
		if err != nil {
			errorPage(w, r, http.StatusInternalServerError, err.Error())
			return
		}

		// Log the successful database upload
		log.Printf("%s: Username: '%s', database '%s%s%s' uploaded', bytes: %v\n", pageName, loggedInUser,
			com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName), numBytes)

		// As the upload was for a standard database, bounce the user to the database view page for it
		http.Redirect(w, r, fmt.Sprintf("/%s/%s?branch=%s", html.EscapeString(dbOwner), html.EscapeString(dbName), html.EscapeString(branchName)), http.StatusSeeOther)
		return
	}

	// ** Live databases **

	// Write the incoming database to a temporary file on disk, and sanity check it
	var tempDB *os.File
	numBytes, tempDB, _, _, err = com.WriteDBtoDisk(loggedInUser, dbOwner, dbFolder, dbName, tempFile)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}
	defer os.Remove(tempDB.Name())

	// Rewind the internal cursor in the temporary file back to the start again
	var newOffset int64
	newOffset, err = tempDB.Seek(0, 0)
	if err != nil {
		log.Printf("Seeking on the temporary file (2nd time) failed: %s", err)
		return
	}
	if newOffset != 0 {
		err = errors.New("Seeking to start of temporary database file didn't work")
		log.Println(err)
		return
	}

	// Store the database in Minio
	err = com.LiveStoreDatabaseMinio(tempDB, dbOwner, dbName, numBytes)
	if err != nil {
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// Log the successful database upload
	log.Printf("%s: Username: '%s', LIVE database '%s%s%s' uploaded', bytes: %v\n", pageName, loggedInUser,
		com.SanitiseLogString(dbOwner), com.SanitiseLogString(dbFolder), com.SanitiseLogString(dbName), numBytes)

	// Send a request to the AMQP backend to set up the database there, ready for querying
	err = com.LiveCreateDB(com.AmqpChan, dbOwner, dbName)
	if err != nil {
		log.Println(err)
		errorPage(w, r, http.StatusInternalServerError, err.Error())
		return
	}

	// As the upload was for a live database, bounce the user to their profile page
	http.Redirect(w, r, fmt.Sprintf("/%s", html.EscapeString(dbOwner)), http.StatusSeeOther)
	return
}

// Handles JSON requests from the front end to toggle watching of a database.
func watchToggleHandler(w http.ResponseWriter, r *http.Request) {
	// Extract the user and database name
	// TODO: Add folder support
	dbOwner, dbName, err := com.GetOD(2, r) // 2 = Ignore "/x/watch/" at the start of the URL
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	dbFolder := "/"

	// Retrieve session data (if any)
	loggedInUser, validSession, err := checkLogin(r)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Ensure we have a valid logged in user
	if validSession != true {
		// No logged in username, so nothing to update
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Toggle on or off the watching of a database by a user
	err = com.ToggleDBWatch(loggedInUser, dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}

	// Invalidate the old memcached entry for the database
	err = com.InvalidateCacheEntry(loggedInUser, dbOwner, dbFolder, dbName, "") // Empty string indicates "for all versions"
	if err != nil {
		// Something went wrong when invalidating memcached entries for the database
		log.Printf("Error when invalidating memcache entries: %s\n", err.Error())
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}

	// Return the updated watchers count
	newStarCount, err := com.DBWatchers(dbOwner, dbFolder, dbName)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprint(w, err.Error())
		return
	}
	w.WriteHeader(http.StatusOK)
	fmt.Fprint(w, newStarCount)
	return
}