Permalink
Find file
296 lines (263 sloc) 8.46 KB
// Copyright 2012 The Gorilla Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package sessions
import (
"encoding/base32"
"io/ioutil"
"net/http"
"os"
"path/filepath"
"strings"
"sync"
"github.com/gorilla/securecookie"
)
// Store is an interface for custom session stores.
//
// See CookieStore and FilesystemStore for examples.
type Store interface {
// Get should return a cached session.
Get(r *http.Request, name string) (*Session, error)
// New should create and return a new session.
//
// Note that New should never return a nil session, even in the case of
// an error if using the Registry infrastructure to cache the session.
New(r *http.Request, name string) (*Session, error)
// Save should persist session to the underlying store implementation.
Save(r *http.Request, w http.ResponseWriter, s *Session) error
}
// CookieStore ----------------------------------------------------------------
// NewCookieStore returns a new CookieStore.
//
// Keys are defined in pairs to allow key rotation, but the common case is
// to set a single authentication key and optionally an encryption key.
//
// The first key in a pair is used for authentication and the second for
// encryption. The encryption key can be set to nil or omitted in the last
// pair, but the authentication key is required in all pairs.
//
// It is recommended to use an authentication key with 32 or 64 bytes.
// The encryption key, if set, must be either 16, 24, or 32 bytes to select
// AES-128, AES-192, or AES-256 modes.
//
// Use the convenience function securecookie.GenerateRandomKey() to create
// strong keys.
func NewCookieStore(keyPairs ...[]byte) *CookieStore {
cs := &CookieStore{
Codecs: securecookie.CodecsFromPairs(keyPairs...),
Options: &Options{
Path: "/",
MaxAge: 86400 * 30,
},
}
cs.MaxAge(cs.Options.MaxAge)
return cs
}
// CookieStore stores sessions using secure cookies.
type CookieStore struct {
Codecs []securecookie.Codec
Options *Options // default configuration
}
// Get returns a session for the given name after adding it to the registry.
//
// It returns a new session if the sessions doesn't exist. Access IsNew on
// the session to check if it is an existing session or a new one.
//
// It returns a new session and an error if the session exists but could
// not be decoded.
func (s *CookieStore) Get(r *http.Request, name string) (*Session, error) {
return GetRegistry(r).Get(s, name)
}
// New returns a session for the given name without adding it to the registry.
//
// The difference between New() and Get() is that calling New() twice will
// decode the session data twice, while Get() registers and reuses the same
// decoded session after the first call.
func (s *CookieStore) New(r *http.Request, name string) (*Session, error) {
session := NewSession(s, name)
opts := *s.Options
session.Options = &opts
session.IsNew = true
var err error
if c, errCookie := r.Cookie(name); errCookie == nil {
err = securecookie.DecodeMulti(name, c.Value, &session.Values,
s.Codecs...)
if err == nil {
session.IsNew = false
}
}
return session, err
}
// Save adds a single session to the response.
func (s *CookieStore) Save(r *http.Request, w http.ResponseWriter,
session *Session) error {
encoded, err := securecookie.EncodeMulti(session.Name(), session.Values,
s.Codecs...)
if err != nil {
return err
}
http.SetCookie(w, NewCookie(session.Name(), encoded, session.Options))
return nil
}
// MaxAge sets the maximum age for the store and the underlying cookie
// implementation. Individual sessions can be deleted by setting Options.MaxAge
// = -1 for that session.
func (s *CookieStore) MaxAge(age int) {
s.Options.MaxAge = age
// Set the maxAge for each securecookie instance.
for _, codec := range s.Codecs {
if sc, ok := codec.(*securecookie.SecureCookie); ok {
sc.MaxAge(age)
}
}
}
// FilesystemStore ------------------------------------------------------------
var fileMutex sync.RWMutex
// NewFilesystemStore returns a new FilesystemStore.
//
// The path argument is the directory where sessions will be saved. If empty
// it will use os.TempDir().
//
// See NewCookieStore() for a description of the other parameters.
func NewFilesystemStore(path string, keyPairs ...[]byte) *FilesystemStore {
if path == "" {
path = os.TempDir()
}
fs := &FilesystemStore{
Codecs: securecookie.CodecsFromPairs(keyPairs...),
Options: &Options{
Path: "/",
MaxAge: 86400 * 30,
},
path: path,
}
fs.MaxAge(fs.Options.MaxAge)
return fs
}
// FilesystemStore stores sessions in the filesystem.
//
// It also serves as a reference for custom stores.
//
// This store is still experimental and not well tested. Feedback is welcome.
type FilesystemStore struct {
Codecs []securecookie.Codec
Options *Options // default configuration
path string
}
// MaxLength restricts the maximum length of new sessions to l.
// If l is 0 there is no limit to the size of a session, use with caution.
// The default for a new FilesystemStore is 4096.
func (s *FilesystemStore) MaxLength(l int) {
for _, c := range s.Codecs {
if codec, ok := c.(*securecookie.SecureCookie); ok {
codec.MaxLength(l)
}
}
}
// Get returns a session for the given name after adding it to the registry.
//
// See CookieStore.Get().
func (s *FilesystemStore) Get(r *http.Request, name string) (*Session, error) {
return GetRegistry(r).Get(s, name)
}
// New returns a session for the given name without adding it to the registry.
//
// See CookieStore.New().
func (s *FilesystemStore) New(r *http.Request, name string) (*Session, error) {
session := NewSession(s, name)
opts := *s.Options
session.Options = &opts
session.IsNew = true
var err error
if c, errCookie := r.Cookie(name); errCookie == nil {
err = securecookie.DecodeMulti(name, c.Value, &session.ID, s.Codecs...)
if err == nil {
err = s.load(session)
if err == nil {
session.IsNew = false
}
}
}
return session, err
}
// Save adds a single session to the response.
//
// If the Options.MaxAge of the session is <= 0 then the session file will be
// deleted from the store path. With this process it enforces the properly
// session cookie handling so no need to trust in the cookie management in the
// web browser.
func (s *FilesystemStore) Save(r *http.Request, w http.ResponseWriter,
session *Session) error {
// Delete if max-age is <= 0
if session.Options.MaxAge <= 0 {
if err := s.erase(session); err != nil {
return err
}
http.SetCookie(w, NewCookie(session.Name(), "", session.Options))
return nil
}
if session.ID == "" {
// Because the ID is used in the filename, encode it to
// use alphanumeric characters only.
session.ID = strings.TrimRight(
base32.StdEncoding.EncodeToString(
securecookie.GenerateRandomKey(32)), "=")
}
if err := s.save(session); err != nil {
return err
}
encoded, err := securecookie.EncodeMulti(session.Name(), session.ID,
s.Codecs...)
if err != nil {
return err
}
http.SetCookie(w, NewCookie(session.Name(), encoded, session.Options))
return nil
}
// MaxAge sets the maximum age for the store and the underlying cookie
// implementation. Individual sessions can be deleted by setting Options.MaxAge
// = -1 for that session.
func (s *FilesystemStore) MaxAge(age int) {
s.Options.MaxAge = age
// Set the maxAge for each securecookie instance.
for _, codec := range s.Codecs {
if sc, ok := codec.(*securecookie.SecureCookie); ok {
sc.MaxAge(age)
}
}
}
// save writes encoded session.Values to a file.
func (s *FilesystemStore) save(session *Session) error {
encoded, err := securecookie.EncodeMulti(session.Name(), session.Values,
s.Codecs...)
if err != nil {
return err
}
filename := filepath.Join(s.path, "session_"+session.ID)
fileMutex.Lock()
defer fileMutex.Unlock()
return ioutil.WriteFile(filename, []byte(encoded), 0600)
}
// load reads a file and decodes its content into session.Values.
func (s *FilesystemStore) load(session *Session) error {
filename := filepath.Join(s.path, "session_"+session.ID)
fileMutex.RLock()
defer fileMutex.RUnlock()
fdata, err := ioutil.ReadFile(filename)
if err != nil {
return err
}
if err = securecookie.DecodeMulti(session.Name(), string(fdata),
&session.Values, s.Codecs...); err != nil {
return err
}
return nil
}
// delete session file
func (s *FilesystemStore) erase(session *Session) error {
filename := filepath.Join(s.path, "session_"+session.ID)
fileMutex.RLock()
defer fileMutex.RUnlock()
err := os.Remove(filename)
return err
}