forgejo-federation/modules/oauth2/oauth2.go

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2014-04-02 19:57:54 +05:30
// Copyright 2014 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package oauth2 contains Martini handlers to provide
// user login via an OAuth 2.0 backend.
package oauth2
import (
"encoding/json"
"fmt"
"net/http"
"net/url"
"strings"
"time"
"code.google.com/p/goauth2/oauth"
"github.com/go-martini/martini"
"github.com/martini-contrib/sessions"
)
const (
codeRedirect = 302
keyToken = "oauth2_token"
keyNextPage = "next"
)
var (
// Path to handle OAuth 2.0 logins.
PathLogin = "/login"
// Path to handle OAuth 2.0 logouts.
PathLogout = "/logout"
// Path to handle callback from OAuth 2.0 backend
// to exchange credentials.
PathCallback = "/oauth2callback"
// Path to handle error cases.
PathError = "/oauth2error"
)
// Represents OAuth2 backend options.
type Options struct {
ClientId string
ClientSecret string
RedirectURL string
Scopes []string
AuthUrl string
TokenUrl string
}
// Represents a container that contains
// user's OAuth 2.0 access and refresh tokens.
type Tokens interface {
Access() string
Refresh() string
IsExpired() bool
ExpiryTime() time.Time
ExtraData() map[string]string
}
type token struct {
oauth.Token
}
func (t *token) ExtraData() map[string]string {
return t.Extra
}
// Returns the access token.
func (t *token) Access() string {
return t.AccessToken
}
// Returns the refresh token.
func (t *token) Refresh() string {
return t.RefreshToken
}
// Returns whether the access token is
// expired or not.
func (t *token) IsExpired() bool {
if t == nil {
return true
}
return t.Expired()
}
// Returns the expiry time of the user's
// access token.
func (t *token) ExpiryTime() time.Time {
return t.Expiry
}
// Formats tokens into string.
func (t *token) String() string {
return fmt.Sprintf("tokens: %v", t)
}
// Returns a new Google OAuth 2.0 backend endpoint.
func Google(opts *Options) martini.Handler {
opts.AuthUrl = "https://accounts.google.com/o/oauth2/auth"
opts.TokenUrl = "https://accounts.google.com/o/oauth2/token"
return NewOAuth2Provider(opts)
}
// Returns a new Github OAuth 2.0 backend endpoint.
func Github(opts *Options) martini.Handler {
opts.AuthUrl = "https://github.com/login/oauth/authorize"
opts.TokenUrl = "https://github.com/login/oauth/access_token"
return NewOAuth2Provider(opts)
}
func Facebook(opts *Options) martini.Handler {
opts.AuthUrl = "https://www.facebook.com/dialog/oauth"
opts.TokenUrl = "https://graph.facebook.com/oauth/access_token"
return NewOAuth2Provider(opts)
}
// Returns a generic OAuth 2.0 backend endpoint.
func NewOAuth2Provider(opts *Options) martini.Handler {
config := &oauth.Config{
ClientId: opts.ClientId,
ClientSecret: opts.ClientSecret,
RedirectURL: opts.RedirectURL,
Scope: strings.Join(opts.Scopes, " "),
AuthURL: opts.AuthUrl,
TokenURL: opts.TokenUrl,
}
transport := &oauth.Transport{
Config: config,
Transport: http.DefaultTransport,
}
return func(s sessions.Session, c martini.Context, w http.ResponseWriter, r *http.Request) {
if r.Method == "GET" {
switch r.URL.Path {
case PathLogin:
login(transport, s, w, r)
case PathLogout:
logout(transport, s, w, r)
case PathCallback:
handleOAuth2Callback(transport, s, w, r)
}
}
tk := unmarshallToken(s)
if tk != nil {
// check if the access token is expired
if tk.IsExpired() && tk.Refresh() == "" {
s.Delete(keyToken)
tk = nil
}
}
// Inject tokens.
c.MapTo(tk, (*Tokens)(nil))
}
}
// Handler that redirects user to the login page
// if user is not logged in.
// Sample usage:
// m.Get("/login-required", oauth2.LoginRequired, func() ... {})
var LoginRequired martini.Handler = func() martini.Handler {
return func(s sessions.Session, c martini.Context, w http.ResponseWriter, r *http.Request) {
token := unmarshallToken(s)
if token == nil || token.IsExpired() {
next := url.QueryEscape(r.URL.RequestURI())
http.Redirect(w, r, PathLogin+"?next="+next, codeRedirect)
}
}
}()
func login(t *oauth.Transport, s sessions.Session, w http.ResponseWriter, r *http.Request) {
next := extractPath(r.URL.Query().Get(keyNextPage))
if s.Get(keyToken) == nil {
// User is not logged in.
http.Redirect(w, r, t.Config.AuthCodeURL(next), codeRedirect)
return
}
// No need to login, redirect to the next page.
http.Redirect(w, r, next, codeRedirect)
}
func logout(t *oauth.Transport, s sessions.Session, w http.ResponseWriter, r *http.Request) {
next := extractPath(r.URL.Query().Get(keyNextPage))
s.Delete(keyToken)
http.Redirect(w, r, next, codeRedirect)
}
func handleOAuth2Callback(t *oauth.Transport, s sessions.Session, w http.ResponseWriter, r *http.Request) {
next := extractPath(r.URL.Query().Get("state"))
code := r.URL.Query().Get("code")
tk, err := t.Exchange(code)
if err != nil {
// Pass the error message, or allow dev to provide its own
// error handler.
http.Redirect(w, r, PathError, codeRedirect)
return
}
// Store the credentials in the session.
val, _ := json.Marshal(tk)
s.Set(keyToken, val)
http.Redirect(w, r, next, codeRedirect)
}
func unmarshallToken(s sessions.Session) (t *token) {
if s.Get(keyToken) == nil {
return
}
data := s.Get(keyToken).([]byte)
var tk oauth.Token
json.Unmarshal(data, &tk)
return &token{tk}
}
func extractPath(next string) string {
n, err := url.Parse(next)
if err != nil {
return "/"
}
return n.Path
}