🔏 Middleware for keeping track of users, login states and permissions
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examples Update documentation and examples Apr 17, 2018
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userstate.go Refactor error handling Dec 11, 2018
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README.md

PermissionSQL Build Status GoDoc

Middleware for keeping track of users, login states and permissions.

Online API Documentation

godoc.org

Features and limitations

  • Uses secure cookies and stores user information in a MariaDB/MySQL database.
  • Suitable for running a local MariaDB/MySQL server, registering/confirming users and managing public/user/admin pages.
  • Also supports connecting to remote MariaDB/MySQL servers.
  • Supports registration and confirmation via generated confirmation codes.
  • Tries to keep things simple.
  • Only supports "public", "user" and "admin" permissions out of the box, but offers functionality for implementing more fine grained permissions, if so desired.
  • Supports Negroni, Martini, Gin and Macaron.
  • Should also work with other frameworks, since the standard http.HandlerFunc is used everywhere.
  • The default permissions can be cleared with the Clear() function.

Connecting

For connecting to a MariaDB/MySQL host that is running locally, the New function can be used. For connecting to a remote server, the NewWithDSN function can be used.

Requirements

  • MariaDB or MySQL
  • Go >= 1.7

Examples

Example for Gin

package main

import (
	"fmt"
	"log"
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"
	"github.com/xyproto/permissionsql"
)

func main() {
	g := gin.New()

	// New permissionsql middleware
	perm, err := permissionsql.New()
	if err != nil {
		log.Fatalln(err)
	}

	// Blank slate, no default permissions
	//perm.Clear()

	// Set up a middleware handler for Gin, with a custom "permission denied" message.
	permissionHandler := func(c *gin.Context) {
		// Check if the user has the right admin/user rights
		if perm.Rejected(c.Writer, c.Request) {
			// Deny the request, don't call other middleware handlers
			c.AbortWithStatus(http.StatusForbidden)
			fmt.Fprint(c.Writer, "Permission denied!")
			return
		}
		// Call the next middleware handler
		c.Next()
	}

	// Logging middleware
	g.Use(gin.Logger())

	// Enable the permissionsql middleware, must come before recovery
	g.Use(permissionHandler)

	// Recovery middleware
	g.Use(gin.Recovery())

	// Get the userstate, used in the handlers below
	userstate := perm.UserState()

	g.GET("/", func(c *gin.Context) {
		msg := ""
		msg += fmt.Sprintf("Has user bob: %v\n", userstate.HasUser("bob"))
		msg += fmt.Sprintf("Logged in on server: %v\n", userstate.IsLoggedIn("bob"))
		msg += fmt.Sprintf("Is confirmed: %v\n", userstate.IsConfirmed("bob"))
		msg += fmt.Sprintf("Username stored in cookies (or blank): %v\n", userstate.Username(c.Request))
		msg += fmt.Sprintf("Current user is logged in, has a valid cookie and *user rights*: %v\n", userstate.UserRights(c.Request))
		msg += fmt.Sprintf("Current user is logged in, has a valid cookie and *admin rights*: %v\n", userstate.AdminRights(c.Request))
		msg += fmt.Sprintln("\nTry: /register, /confirm, /remove, /login, /logout, /makeadmin, /clear, /data and /admin")
		c.String(http.StatusOK, msg)
	})

	g.GET("/register", func(c *gin.Context) {
		userstate.AddUser("bob", "hunter1", "bob@zombo.com")
		c.String(http.StatusOK, fmt.Sprintf("User bob was created: %v\n", userstate.HasUser("bob")))
	})

	g.GET("/confirm", func(c *gin.Context) {
		userstate.MarkConfirmed("bob")
		c.String(http.StatusOK, fmt.Sprintf("User bob was confirmed: %v\n", userstate.IsConfirmed("bob")))
	})

	g.GET("/remove", func(c *gin.Context) {
		userstate.RemoveUser("bob")
		c.String(http.StatusOK, fmt.Sprintf("User bob was removed: %v\n", !userstate.HasUser("bob")))
	})

	g.GET("/login", func(c *gin.Context) {
		// Headers will be written, for storing a cookie
		userstate.Login(c.Writer, "bob")
		c.String(http.StatusOK, fmt.Sprintf("bob is now logged in: %v\n", userstate.IsLoggedIn("bob")))
	})

	g.GET("/logout", func(c *gin.Context) {
		userstate.Logout("bob")
		c.String(http.StatusOK, fmt.Sprintf("bob is now logged out: %v\n", !userstate.IsLoggedIn("bob")))
	})

	g.GET("/makeadmin", func(c *gin.Context) {
		userstate.SetAdminStatus("bob")
		c.String(http.StatusOK, fmt.Sprintf("bob is now administrator: %v\n", userstate.IsAdmin("bob")))
	})

	g.GET("/clear", func(c *gin.Context) {
		userstate.ClearCookie(c.Writer)
		c.String(http.StatusOK, "Clearing cookie")
	})

	g.GET("/data", func(c *gin.Context) {
		c.String(http.StatusOK, "user page that only logged in users must see!")
	})

	g.GET("/admin", func(c *gin.Context) {
		c.String(http.StatusOK, "super secret information that only logged in administrators must see!\n\n")
		if usernames, err := userstate.AllUsernames(); err == nil {
			c.String(http.StatusOK, "list of all users: "+strings.Join(usernames, ", "))
		}
	})

	// Serve
	g.Run(":3000")
}

Example for just net/http

package main

import (
	"fmt"
	"log"
	"net/http"
	"strings"
	"time"

	"github.com/xyproto/permissionsql"
	"github.com/xyproto/pinterface"
)

type permissionHandler struct {
	// perm is a Permissions structure that can be used to deny requests
	// and acquire the UserState. By using `pinterface.IPermissions` instead
	// of `*permissions.Permissions`, the code is compatible with not only
	// `permissions2`, but also other modules that uses other database
	// backends, like `permissionbolt` which uses Bolt.
	perm pinterface.IPermissions

	// The HTTP multiplexer
	mux *http.ServeMux
}

// Implement the ServeHTTP method to make a permissionHandler a http.Handler
func (ph *permissionHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	// Check if the user has the right admin/user rights
	if ph.perm.Rejected(w, req) {
		// Let the user know, by calling the custom "permission denied" function
		ph.perm.DenyFunction()(w, req)
		// Reject the request
		return
	}
	// Serve the requested page if permissions were granted
	ph.mux.ServeHTTP(w, req)
}

func main() {
	mux := http.NewServeMux()

	// New permissions middleware
	perm, err := permissionsql.New()
	if err != nil {
		log.Fatalln(err)
	}

	// Blank slate, no default permissions
	//perm.Clear()

	// Get the userstate, used in the handlers below
	userstate := perm.UserState()

	mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
		fmt.Fprintf(w, "Has user bob: %v\n", userstate.HasUser("bob"))
		fmt.Fprintf(w, "Logged in on server: %v\n", userstate.IsLoggedIn("bob"))
		fmt.Fprintf(w, "Is confirmed: %v\n", userstate.IsConfirmed("bob"))
		fmt.Fprintf(w, "Username stored in cookies (or blank): %v\n", userstate.Username(req))
		fmt.Fprintf(w, "Current user is logged in, has a valid cookie and *user rights*: %v\n", userstate.UserRights(req))
		fmt.Fprintf(w, "Current user is logged in, has a valid cookie and *admin rights*: %v\n", userstate.AdminRights(req))
		fmt.Fprintf(w, "\nTry: /register, /confirm, /remove, /login, /logout, /makeadmin, /clear, /data and /admin")
	})

	mux.HandleFunc("/register", func(w http.ResponseWriter, req *http.Request) {
		userstate.AddUser("bob", "hunter1", "bob@zombo.com")
		fmt.Fprintf(w, "User bob was created: %v\n", userstate.HasUser("bob"))
	})

	mux.HandleFunc("/confirm", func(w http.ResponseWriter, req *http.Request) {
		userstate.MarkConfirmed("bob")
		fmt.Fprintf(w, "User bob was confirmed: %v\n", userstate.IsConfirmed("bob"))
	})

	mux.HandleFunc("/remove", func(w http.ResponseWriter, req *http.Request) {
		userstate.RemoveUser("bob")
		fmt.Fprintf(w, "User bob was removed: %v\n", !userstate.HasUser("bob"))
	})

	mux.HandleFunc("/login", func(w http.ResponseWriter, req *http.Request) {
		userstate.Login(w, "bob")
		fmt.Fprintf(w, "bob is now logged in: %v\n", userstate.IsLoggedIn("bob"))
	})

	mux.HandleFunc("/logout", func(w http.ResponseWriter, req *http.Request) {
		userstate.Logout("bob")
		fmt.Fprintf(w, "bob is now logged out: %v\n", !userstate.IsLoggedIn("bob"))
	})

	mux.HandleFunc("/makeadmin", func(w http.ResponseWriter, req *http.Request) {
		userstate.SetAdminStatus("bob")
		fmt.Fprintf(w, "bob is now administrator: %v\n", userstate.IsAdmin("bob"))
	})

	mux.HandleFunc("/clear", func(w http.ResponseWriter, req *http.Request) {
		userstate.ClearCookie(w)
		fmt.Fprintf(w, "Clearing cookie")
	})

	mux.HandleFunc("/data", func(w http.ResponseWriter, req *http.Request) {
		fmt.Fprintf(w, "user page that only logged in users must see!")
	})

	mux.HandleFunc("/admin", func(w http.ResponseWriter, req *http.Request) {
		fmt.Fprintf(w, "super secret information that only logged in administrators must see!\n\n")
		if usernames, err := userstate.AllUsernames(); err == nil {
			fmt.Fprintf(w, "list of all users: "+strings.Join(usernames, ", "))
		}
	})

	// Custom handler for when permissions are denied
	perm.SetDenyFunction(func(w http.ResponseWriter, req *http.Request) {
		http.Error(w, "Permission denied!", http.StatusForbidden)
	})

	// Configure the HTTP server and permissionHandler struct
	s := &http.Server{
		Addr:           ":3000",
		Handler:        &permissionHandler{perm, mux},
		ReadTimeout:    10 * time.Second,
		WriteTimeout:   10 * time.Second,
		MaxHeaderBytes: 1 << 20,
	}

	log.Println("Listening for requests on port 3000")

	// Start listening
	log.Fatal(s.ListenAndServe())
}

Default permissions

  • Visiting the /admin path prefix requires the user to be logged in with admin rights, by default.
  • These path prefixes requires the user to be logged in, by default: /repo and /data
  • These path prefixes are public by default: /, /login, /register, /style, /img, /js, /favicon.ico, /robots.txt and /sitemap_index.xml

The default permissions can be cleared with the Clear() function.

Coding style

  • The code shall always be formatted with go fmt.

Password hashing

  • bcrypt is used by default for hashing passwords. sha256 is also supported.
  • By default, all new password will be hashed with bcrypt.
  • For backwards compatibility, old password hashes with the length of a sha256 hash will be checked with sha256. To disable this behavior, and only ever use bcrypt, add this line: userstate.SetPasswordAlgo("bcrypt")

Setting and getting properties for users

  • Setting a property:
username := "bob"
propertyName := "clever"
propertyValue := "yes"

userstate.Users().Set(username, propertyName, propertyValue)
  • Getting a property:
username := "bob"
propertyName := "clever"
propertyValue, err := userstate.Users().Get(username, propertyName)
if err != nil {
	log.Print(err)
	return err
}
fmt.Printf("%s is %s: %s\n", username, propertyName, propertyValue)

Passing userstate between functions, files and to other Go packages

Using the *pinterface.IUserState type (from the pinterface package) makes it possible to pass UserState structs between functions, also in other packages. By using this interface, it is possible to seamlessly change the database backend from, for instance, PostgreSQL (pstore) to BoltDB (permissionbolt) or Redis (permissions2).

pstore, permissionsql, permissionbolt and permissions2 are interchangeable.

General information