oauth2/google/google.go

116 lines
3.6 KiB
Go

// Copyright 2014 The oauth2 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 google provides support for making
// OAuth2 authorized and authenticated HTTP requests
// to Google APIs. It supports Web server, client-side,
// service accounts, Google Compute Engine service accounts,
// and Google App Engine service accounts authorization
// and authentications flows:
//
// For more information, please read
// https://developers.google.com/accounts/docs/OAuth2.
package google // import "golang.org/x/oauth2/google"
import (
"encoding/json"
"fmt"
"net"
"net/http"
"time"
"golang.org/x/oauth2"
)
// Endpoint is Google's OAuth 2.0 endpoint.
var Endpoint = oauth2.Endpoint{
AuthURL: "https://accounts.google.com/o/oauth2/auth",
TokenURL: "https://accounts.google.com/o/oauth2/token",
}
// JWTTokenURL is Google's OAuth 2.0 token URL to use with the JWT flow.
const JWTTokenURL = "https://accounts.google.com/o/oauth2/token"
// JWTConfigFromJSON uses a Google Developers service account JSON key file to read
// the credentials that authorize and authenticate the requests.
// Create a service account on "Credentials" page under "APIs & Auth" for your
// project at https://console.developers.google.com to download a JSON key file.
func JWTConfigFromJSON(ctx oauth2.Context, jsonKey []byte, scope ...string) (*oauth2.JWTConfig, error) {
var key struct {
Email string `json:"client_email"`
PrivateKey string `json:"private_key"`
}
if err := json.Unmarshal(jsonKey, &key); err != nil {
return nil, err
}
return &oauth2.JWTConfig{
Email: key.Email,
PrivateKey: []byte(key.PrivateKey),
Scopes: scope,
TokenURL: JWTTokenURL,
}, nil
}
type metaTokenRespBody struct {
AccessToken string `json:"access_token"`
ExpiresIn time.Duration `json:"expires_in"`
TokenType string `json:"token_type"`
}
// ComputeTokenSource returns a token source that fetches access tokens
// from Google Compute Engine (GCE)'s metadata server. It's only valid to use
// this token source if your program is running on a GCE instance.
// If no account is specified, "default" is used.
// Further information about retrieving access tokens from the GCE metadata
// server can be found at https://cloud.google.com/compute/docs/authentication.
func ComputeTokenSource(account string) oauth2.TokenSource {
return &computeSource{account: account}
}
type computeSource struct {
account string
}
var metaClient = &http.Client{
Transport: &http.Transport{
Dial: (&net.Dialer{
Timeout: 750 * time.Millisecond,
KeepAlive: 30 * time.Second,
}).Dial,
ResponseHeaderTimeout: 750 * time.Millisecond,
},
}
func (cs *computeSource) Token() (*oauth2.Token, error) {
acct := cs.account
if acct == "" {
acct = "default"
}
u := "http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/" + acct + "/token"
req, err := http.NewRequest("GET", u, nil)
if err != nil {
return nil, err
}
req.Header.Add("X-Google-Metadata-Request", "True")
resp, err := metaClient.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode < 200 || resp.StatusCode > 299 {
return nil, fmt.Errorf("oauth2: can't retrieve a token from metadata server, status code: %d", resp.StatusCode)
}
var tokenResp metaTokenRespBody
err = json.NewDecoder(resp.Body).Decode(&tokenResp)
if err != nil {
return nil, err
}
return &oauth2.Token{
AccessToken: tokenResp.AccessToken,
TokenType: tokenResp.TokenType,
Expiry: time.Now().Add(tokenResp.ExpiresIn * time.Second),
}, nil
}