2014-09-09 09:57:48 +03:00
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// Copyright 2011 The goauth2 Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package oauth supports making OAuth2-authenticated HTTP requests.
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//
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// Example usage:
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//
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// // Specify your configuration. (typically as a global variable)
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// var config = &oauth.Config{
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// ClientId: YOUR_CLIENT_ID,
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// ClientSecret: YOUR_CLIENT_SECRET,
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// Scope: "https://www.googleapis.com/auth/buzz",
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// AuthURL: "https://accounts.google.com/o/oauth2/auth",
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// TokenURL: "https://accounts.google.com/o/oauth2/token",
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// RedirectURL: "http://you.example.org/handler",
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// }
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//
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// // A landing page redirects to the OAuth provider to get the auth code.
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// func landing(w http.ResponseWriter, r *http.Request) {
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// http.Redirect(w, r, config.AuthCodeURL("foo"), http.StatusFound)
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// }
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//
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// // The user will be redirected back to this handler, that takes the
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// // "code" query parameter and Exchanges it for an access token.
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// func handler(w http.ResponseWriter, r *http.Request) {
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// t := &oauth.Transport{Config: config}
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// t.Exchange(r.FormValue("code"))
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// // The Transport now has a valid Token. Create an *http.Client
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// // with which we can make authenticated API requests.
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// c := t.Client()
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// c.Post(...)
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// // ...
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// // btw, r.FormValue("state") == "foo"
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// }
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//
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2015-04-07 10:20:55 +02:00
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package oauth2
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2014-09-09 09:57:48 +03:00
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import (
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"io/ioutil"
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"mime"
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"net/http"
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"net/url"
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"os"
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"strconv"
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"strings"
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"sync"
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"time"
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)
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// OAuthError is the error type returned by many operations.
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//
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// In retrospect it should not exist. Don't depend on it.
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type OAuthError struct {
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prefix string
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msg string
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}
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func (oe OAuthError) Error() string {
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return "OAuthError: " + oe.prefix + ": " + oe.msg
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}
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// Cache specifies the methods that implement a Token cache.
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type Cache interface {
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Token() (*Token, error)
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PutToken(*Token) error
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}
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// CacheFile implements Cache. Its value is the name of the file in which
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// the Token is stored in JSON format.
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type CacheFile string
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func (f CacheFile) Token() (*Token, error) {
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file, err := os.Open(string(f))
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if err != nil {
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return nil, OAuthError{"CacheFile.Token", err.Error()}
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}
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defer file.Close()
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tok := &Token{}
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if err := json.NewDecoder(file).Decode(tok); err != nil {
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return nil, OAuthError{"CacheFile.Token", err.Error()}
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}
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return tok, nil
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}
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func (f CacheFile) PutToken(tok *Token) error {
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file, err := os.OpenFile(string(f), os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
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if err != nil {
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return OAuthError{"CacheFile.PutToken", err.Error()}
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}
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if err := json.NewEncoder(file).Encode(tok); err != nil {
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file.Close()
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return OAuthError{"CacheFile.PutToken", err.Error()}
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}
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if err := file.Close(); err != nil {
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return OAuthError{"CacheFile.PutToken", err.Error()}
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}
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return nil
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}
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// Config is the configuration of an OAuth consumer.
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type Config struct {
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// ClientId is the OAuth client identifier used when communicating with
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// the configured OAuth provider.
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ClientId string
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// ClientSecret is the OAuth client secret used when communicating with
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// the configured OAuth provider.
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ClientSecret string
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// Scope identifies the level of access being requested. Multiple scope
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// values should be provided as a space-delimited string.
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Scope string
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// AuthURL is the URL the user will be directed to in order to grant
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// access.
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AuthURL string
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// TokenURL is the URL used to retrieve OAuth tokens.
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TokenURL string
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// RedirectURL is the URL to which the user will be returned after
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// granting (or denying) access.
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RedirectURL string
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// TokenCache allows tokens to be cached for subsequent requests.
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TokenCache Cache
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// AccessType is an OAuth extension that gets sent as the
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// "access_type" field in the URL from AuthCodeURL.
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// See https://developers.google.com/accounts/docs/OAuth2WebServer.
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// It may be "online" (the default) or "offline".
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// If your application needs to refresh access tokens when the
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// user is not present at the browser, then use offline. This
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// will result in your application obtaining a refresh token
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// the first time your application exchanges an authorization
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// code for a user.
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AccessType string
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// ApprovalPrompt indicates whether the user should be
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// re-prompted for consent. If set to "auto" (default) the
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// user will be prompted only if they haven't previously
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// granted consent and the code can only be exchanged for an
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// access token.
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// If set to "force" the user will always be prompted, and the
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// code can be exchanged for a refresh token.
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ApprovalPrompt string
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}
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// Token contains an end-user's tokens.
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// This is the data you must store to persist authentication.
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type Token struct {
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AccessToken string
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RefreshToken string
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Expiry time.Time // If zero the token has no (known) expiry time.
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// Extra optionally contains extra metadata from the server
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// when updating a token. The only current key that may be
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// populated is "id_token". It may be nil and will be
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// initialized as needed.
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Extra map[string]string
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}
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// Expired reports whether the token has expired or is invalid.
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func (t *Token) Expired() bool {
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if t.AccessToken == "" {
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return true
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}
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if t.Expiry.IsZero() {
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return false
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}
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return t.Expiry.Before(time.Now())
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}
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// Transport implements http.RoundTripper. When configured with a valid
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// Config and Token it can be used to make authenticated HTTP requests.
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//
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// t := &oauth.Transport{config}
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// t.Exchange(code)
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// // t now contains a valid Token
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// r, _, err := t.Client().Get("http://example.org/url/requiring/auth")
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//
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// It will automatically refresh the Token if it can,
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// updating the supplied Token in place.
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type Transport struct {
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*Config
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*Token
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// mu guards modifying the token.
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mu sync.Mutex
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// Transport is the HTTP transport to use when making requests.
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// It will default to http.DefaultTransport if nil.
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// (It should never be an oauth.Transport.)
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Transport http.RoundTripper
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}
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// Client returns an *http.Client that makes OAuth-authenticated requests.
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func (t *Transport) Client() *http.Client {
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return &http.Client{Transport: t}
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}
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func (t *Transport) transport() http.RoundTripper {
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if t.Transport != nil {
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return t.Transport
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}
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return http.DefaultTransport
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}
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// AuthCodeURL returns a URL that the end-user should be redirected to,
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// so that they may obtain an authorization code.
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func (c *Config) AuthCodeURL(state string) string {
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url_, err := url.Parse(c.AuthURL)
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if err != nil {
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panic("AuthURL malformed: " + err.Error())
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}
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q := url.Values{
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"response_type": {"code"},
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"client_id": {c.ClientId},
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"state": condVal(state),
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"scope": condVal(c.Scope),
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"redirect_uri": condVal(c.RedirectURL),
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"access_type": condVal(c.AccessType),
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"approval_prompt": condVal(c.ApprovalPrompt),
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}.Encode()
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if url_.RawQuery == "" {
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url_.RawQuery = q
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} else {
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url_.RawQuery += "&" + q
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}
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return url_.String()
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}
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func condVal(v string) []string {
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if v == "" {
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return nil
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}
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return []string{v}
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}
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// Exchange takes a code and gets access Token from the remote server.
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func (t *Transport) Exchange(code string) (*Token, error) {
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if t.Config == nil {
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return nil, OAuthError{"Exchange", "no Config supplied"}
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}
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// If the transport or the cache already has a token, it is
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// passed to `updateToken` to preserve existing refresh token.
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tok := t.Token
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if tok == nil && t.TokenCache != nil {
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tok, _ = t.TokenCache.Token()
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}
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if tok == nil {
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tok = new(Token)
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}
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err := t.updateToken(tok, url.Values{
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"grant_type": {"authorization_code"},
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"redirect_uri": {t.RedirectURL},
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"scope": {t.Scope},
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"code": {code},
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})
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if err != nil {
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return nil, err
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}
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t.Token = tok
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if t.TokenCache != nil {
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return tok, t.TokenCache.PutToken(tok)
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}
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return tok, nil
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}
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// RoundTrip executes a single HTTP transaction using the Transport's
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// Token as authorization headers.
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//
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// This method will attempt to renew the Token if it has expired and may return
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// an error related to that Token renewal before attempting the client request.
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// If the Token cannot be renewed a non-nil os.Error value will be returned.
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// If the Token is invalid callers should expect HTTP-level errors,
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// as indicated by the Response's StatusCode.
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func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
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accessToken, err := t.getAccessToken()
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if err != nil {
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return nil, err
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}
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// To set the Authorization header, we must make a copy of the Request
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// so that we don't modify the Request we were given.
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// This is required by the specification of http.RoundTripper.
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req = cloneRequest(req)
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req.Header.Set("Authorization", "Bearer "+accessToken)
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// Make the HTTP request.
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return t.transport().RoundTrip(req)
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}
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func (t *Transport) getAccessToken() (string, error) {
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t.mu.Lock()
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defer t.mu.Unlock()
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if t.Token == nil {
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if t.Config == nil {
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return "", OAuthError{"RoundTrip", "no Config supplied"}
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}
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if t.TokenCache == nil {
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return "", OAuthError{"RoundTrip", "no Token supplied"}
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}
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var err error
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t.Token, err = t.TokenCache.Token()
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if err != nil {
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return "", err
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}
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}
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// Refresh the Token if it has expired.
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if t.Expired() {
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if err := t.Refresh(); err != nil {
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return "", err
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}
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}
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if t.AccessToken == "" {
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return "", errors.New("no access token obtained from refresh")
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}
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return t.AccessToken, nil
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}
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// cloneRequest returns a clone of the provided *http.Request.
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// The clone is a shallow copy of the struct and its Header map.
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func cloneRequest(r *http.Request) *http.Request {
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// shallow copy of the struct
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r2 := new(http.Request)
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*r2 = *r
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// deep copy of the Header
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r2.Header = make(http.Header)
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for k, s := range r.Header {
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r2.Header[k] = s
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}
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return r2
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}
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// Refresh renews the Transport's AccessToken using its RefreshToken.
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func (t *Transport) Refresh() error {
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if t.Token == nil {
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return OAuthError{"Refresh", "no existing Token"}
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}
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if t.RefreshToken == "" {
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return OAuthError{"Refresh", "Token expired; no Refresh Token"}
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}
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if t.Config == nil {
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return OAuthError{"Refresh", "no Config supplied"}
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}
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err := t.updateToken(t.Token, url.Values{
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"grant_type": {"refresh_token"},
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"refresh_token": {t.RefreshToken},
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})
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if err != nil {
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return err
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}
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if t.TokenCache != nil {
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return t.TokenCache.PutToken(t.Token)
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}
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return nil
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}
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// AuthenticateClient gets an access Token using the client_credentials grant
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// type.
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func (t *Transport) AuthenticateClient() error {
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if t.Config == nil {
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return OAuthError{"Exchange", "no Config supplied"}
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}
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if t.Token == nil {
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t.Token = &Token{}
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}
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return t.updateToken(t.Token, url.Values{"grant_type": {"client_credentials"}})
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}
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// providerAuthHeaderWorks reports whether the OAuth2 server identified by the tokenURL
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// implements the OAuth2 spec correctly
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// See https://code.google.com/p/goauth2/issues/detail?id=31 for background.
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// In summary:
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// - Reddit only accepts client secret in the Authorization header
|
|
|
|
// - Dropbox accepts either it in URL param or Auth header, but not both.
|
|
|
|
// - Google only accepts URL param (not spec compliant?), not Auth header
|
|
|
|
func providerAuthHeaderWorks(tokenURL string) bool {
|
|
|
|
if strings.HasPrefix(tokenURL, "https://accounts.google.com/") ||
|
|
|
|
strings.HasPrefix(tokenURL, "https://github.com/") ||
|
|
|
|
strings.HasPrefix(tokenURL, "https://api.instagram.com/") ||
|
|
|
|
strings.HasPrefix(tokenURL, "https://www.douban.com/") {
|
|
|
|
// Some sites fail to implement the OAuth2 spec fully.
|
|
|
|
return false
|
|
|
|
}
|
|
|
|
|
|
|
|
// Assume the provider implements the spec properly
|
|
|
|
// otherwise. We can add more exceptions as they're
|
|
|
|
// discovered. We will _not_ be adding configurable hooks
|
|
|
|
// to this package to let users select server bugs.
|
|
|
|
return true
|
|
|
|
}
|
|
|
|
|
|
|
|
// updateToken mutates both tok and v.
|
|
|
|
func (t *Transport) updateToken(tok *Token, v url.Values) error {
|
|
|
|
v.Set("client_id", t.ClientId)
|
|
|
|
v.Set("client_secret", t.ClientSecret)
|
|
|
|
client := &http.Client{Transport: t.transport()}
|
|
|
|
req, err := http.NewRequest("POST", t.TokenURL, strings.NewReader(v.Encode()))
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
|
|
|
|
req.SetBasicAuth(t.ClientId, t.ClientSecret)
|
|
|
|
r, err := client.Do(req)
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
defer r.Body.Close()
|
|
|
|
if r.StatusCode != 200 {
|
|
|
|
return OAuthError{"updateToken", "Unexpected HTTP status " + r.Status}
|
|
|
|
}
|
|
|
|
var b struct {
|
|
|
|
Access string `json:"access_token"`
|
|
|
|
Refresh string `json:"refresh_token"`
|
|
|
|
ExpiresIn int64 `json:"expires_in"` // seconds
|
|
|
|
Id string `json:"id_token"`
|
|
|
|
}
|
|
|
|
|
|
|
|
body, err := ioutil.ReadAll(io.LimitReader(r.Body, 1<<20))
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
|
|
|
|
content, _, _ := mime.ParseMediaType(r.Header.Get("Content-Type"))
|
|
|
|
switch content {
|
|
|
|
case "application/x-www-form-urlencoded", "text/plain":
|
|
|
|
vals, err := url.ParseQuery(string(body))
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
|
|
|
|
b.Access = vals.Get("access_token")
|
|
|
|
b.Refresh = vals.Get("refresh_token")
|
|
|
|
b.ExpiresIn, _ = strconv.ParseInt(vals.Get("expires_in"), 10, 64)
|
|
|
|
b.Id = vals.Get("id_token")
|
|
|
|
default:
|
|
|
|
if err = json.Unmarshal(body, &b); err != nil {
|
|
|
|
return fmt.Errorf("got bad response from server: %q", body)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if b.Access == "" {
|
|
|
|
return errors.New("received empty access token from authorization server")
|
|
|
|
}
|
|
|
|
tok.AccessToken = b.Access
|
|
|
|
// Don't overwrite `RefreshToken` with an empty value
|
|
|
|
if b.Refresh != "" {
|
|
|
|
tok.RefreshToken = b.Refresh
|
|
|
|
}
|
|
|
|
if b.ExpiresIn == 0 {
|
|
|
|
tok.Expiry = time.Time{}
|
|
|
|
} else {
|
|
|
|
tok.Expiry = time.Now().Add(time.Duration(b.ExpiresIn) * time.Second)
|
|
|
|
}
|
|
|
|
if b.Id != "" {
|
|
|
|
if tok.Extra == nil {
|
|
|
|
tok.Extra = make(map[string]string)
|
|
|
|
}
|
|
|
|
tok.Extra["id_token"] = b.Id
|
|
|
|
}
|
|
|
|
return nil
|
|
|
|
}
|