必须使用 OAuth 2.0 凭据授权对 Google 镜像 API 的请求。如果您的应用需要代表用户访问 Google API（例如，用户离线），您应该使用服务器端流程。此方法需要将一次性授权代码从您的客户端传递到您的服务器，以用于获取服务器的访问令牌和刷新令牌。
创建客户端 ID 和客户端密钥
首先，您需要为应用激活 Google 镜像 API。您可以在 Google API 控制台中为您的 API 项目执行此操作。
- 在 Google API 控制台中创建一个 API 项目。
- 在 API 项目中选择服务标签页，然后启用 Google 镜像 API。
- 选择 API 项目中的 API 访问权限标签页，然后点击创建 OAuth 2.0 客户端 ID。
- 在品牌信息部分，为您的应用提供名称（例如“My Glass service”），然后点击下一步。您可以选择是否提供产品徽标。
- 在客户端 ID 设置部分，执行以下操作：
- 对于应用类型，请选择 Web 应用。
- 点击标题您的网站或主机名旁边的更多选项链接。
- 在已获授权的重定向 URI 和 JavaScript 来源字段中列出您的主机名。
- 点击创建客户端 ID。
- 在 API 访问权限页面中，找到适用于 Web 应用的客户端 ID 部分，并记下客户端 ID 和客户端密钥值。
处理授权请求
当用户首次加载您的应用时，系统会向用户显示一个对话框，授权您的应用访问其 Google Glass 帐号及请求的权限范围。完成此初始授权后，只有当应用的客户端 ID 更改或请求的范围发生更改时，用户才会看到权限对话框。
对用户进行身份验证
此首次登录会返回一个授权结果对象，如果成功，该对象将包含授权代码。
用授权代码换取访问令牌
授权代码是一次性代码，您的服务器可以用它来换取访问令牌。此访问令牌会传递给 Google 镜像 API 以授予您的应用在有限时间内访问用户数据的权限。
如果您的应用需要 offline 访问权限，则您的应用在第一次交换授权代码时，也会收到一个刷新令牌，该令牌用于在上一个令牌过期后用于接收新的访问令牌。您的应用会将此刷新令牌（通常存储在您服务器的数据库中）以供日后使用。
以下代码示例演示了如何用授权代码交换具有 offline 访问权限的访问令牌并存储刷新令牌。
Java
将 CLIENTSECRETS_LOCATION 值替换为 client_secrets.json 文件的位置。
import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.auth.oauth2.GoogleTokenResponse;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.jackson.JacksonFactory;
import com.google.api.services.oauth2.Oauth2;
import com.google.api.services.oauth2.model.Userinfo;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
// ...
class MyClass {
// Path to client_secrets.json which should contain a JSON document such as:
// {
// "web": {
// "client_id": "[[YOUR_CLIENT_ID]]",
// "client_secret": "[[YOUR_CLIENT_SECRET]]",
// "auth_uri": "https://accounts.google.com/o/oauth2/auth",
// "token_uri": "https://accounts.google.com/o/oauth2/token"
// }
// }
private static final String CLIENTSECRETS_LOCATION = "client_secrets.json";
private static final String REDIRECT_URI = "<YOUR_REGISTERED_REDIRECT_URI>";
private static final List<String> SCOPES = Arrays.asList(
"https://www.googleapis.com/auth/glass.timeline",
"https://www.googleapis.com/auth/userinfo.profile");
private static GoogleAuthorizationCodeFlow flow = null;
/**
* Exception thrown when an error occurred while retrieving credentials.
*/
public static class GetCredentialsException extends Exception {
protected String authorizationUrl;
/**
* Construct a GetCredentialsException.
*
* @param authorizationUrl The authorization URL to redirect the user to.
*/
public GetCredentialsException(String authorizationUrl) {
this.authorizationUrl = authorizationUrl;
}
/**
* Set the authorization URL.
*/
public void setAuthorizationUrl(String authorizationUrl) {
this.authorizationUrl = authorizationUrl;
}
/**
* @return the authorizationUrl
*/
public String getAuthorizationUrl() {
return authorizationUrl;
}
}
/**
* Exception thrown when a code exchange has failed.
*/
public static class CodeExchangeException extends GetCredentialsException {
/**
* Construct a CodeExchangeException.
*
* @param authorizationUrl The authorization URL to redirect the user to.
*/
public CodeExchangeException(String authorizationUrl) {
super(authorizationUrl);
}
}
/**
* Exception thrown when no refresh token has been found.
*/
public static class NoRefreshTokenException extends GetCredentialsException {
/**
* Construct a NoRefreshTokenException.
*
* @param authorizationUrl The authorization URL to redirect the user to.
*/
public NoRefreshTokenException(String authorizationUrl) {
super(authorizationUrl);
}
}
/**
* Exception thrown when no user ID could be retrieved.
*/
private static class NoUserIdException extends Exception {
}
/**
* Retrieved stored credentials for the provided user ID.
*
* @param userId User's ID.
* @return Stored Credential if found, {@code null} otherwise.
*/
static Credential getStoredCredentials(String userId) {
// TODO: Implement this method to work with your database. Instantiate a new
// Credential instance with stored accessToken and refreshToken.
throw new UnsupportedOperationException();
}
/**
* Store OAuth 2.0 credentials in the application's database.
*
* @param userId User's ID.
* @param credentials The OAuth 2.0 credentials to store.
*/
static void storeCredentials(String userId, Credential credentials) {
// TODO: Implement this method to work with your database.
// Store the credentials.getAccessToken() and credentials.getRefreshToken()
// string values in your database.
throw new UnsupportedOperationException();
}
/**
* Build an authorization flow and store it as a static class attribute.
*
* @return GoogleAuthorizationCodeFlow instance.
* @throws IOException Unable to load client_secrets.json.
*/
static GoogleAuthorizationCodeFlow getFlow() throws IOException {
if (flow == null) {
HttpTransport httpTransport = new NetHttpTransport();
JacksonFactory jsonFactory = new JacksonFactory();
GoogleClientSecrets clientSecrets =
GoogleClientSecrets.load(jsonFactory,
MyClass.class.getResourceAsStream(CLIENTSECRETS_LOCATION));
flow =
new GoogleAuthorizationCodeFlow.Builder(httpTransport, jsonFactory, clientSecrets, SCOPES)
.setAccessType("offline").setApprovalPrompt("force").build();
}
return flow;
}
/**
* Exchange an authorization code for OAuth 2.0 credentials.
*
* @param authorizationCode Authorization code to exchange for OAuth 2.0
* credentials.
* @return OAuth 2.0 credentials.
* @throws CodeExchangeException An error occurred.
*/
static Credential exchangeCode(String authorizationCode)
throws CodeExchangeException {
try {
GoogleAuthorizationCodeFlow flow = getFlow();
GoogleTokenResponse response =
flow.newTokenRequest(authorizationCode).setRedirectUri(REDIRECT_URI).execute();
return flow.createAndStoreCredential(response, null);
} catch (IOException e) {
System.err.println("An error occurred: " + e);
throw new CodeExchangeException(null);
}
}
/**
* Send a request to the UserInfo API to retrieve the user's information.
*
* @param credentials OAuth 2.0 credentials to authorize the request.
* @return User's information.
* @throws NoUserIdException An error occurred.
*/
static Userinfo getUserInfo(Credential credentials)
throws NoUserIdException {
Oauth2 userInfoService =
new Oauth2.Builder(new NetHttpTransport(), new JacksonFactory(), credentials).build();
Userinfo userInfo = null;
try {
userInfo = userInfoService.userinfo().get().execute();
} catch (IOException e) {
System.err.println("An error occurred: " + e);
}
if (userInfo != null && userInfo.getId() != null) {
return userInfo;
} else {
throw new NoUserIdException();
}
}
/**
* Retrieve the authorization URL.
*
* @param userId User's Google ID.
* @param state State for the authorization URL.
* @return Authorization URL to redirect the user to.
* @throws IOException Unable to load client_secrets.json.
*/
public static String getAuthorizationUrl(String userId, String state) throws IOException {
GoogleAuthorizationCodeRequestUrl urlBuilder =
getFlow().newAuthorizationUrl().setRedirectUri(REDIRECT_URI).setState(state);
urlBuilder.set("user_id", userId);
return urlBuilder.build();
}
/**
* Retrieve credentials using the provided authorization code.
*
* This function exchanges the authorization code for an access token and
* queries the UserInfo API to retrieve the user's Google ID. If a
* refresh token has been retrieved along with an access token, it is stored
* in the application database using the user's Google ID as key. If no
* refresh token has been retrieved, the function checks in the application
* database for one and returns it if found or throws a NoRefreshTokenException
* with the authorization URL to redirect the user to.
*
* @param authorizationCode Authorization code to use to retrieve an access
* token.
* @param state State to set to the authorization URL in case of error.
* @return OAuth 2.0 credentials instance containing an access and refresh
* token.
* @throws NoRefreshTokenException No refresh token could be retrieved from
* the available sources.
* @throws IOException Unable to load client_secrets.json.
*/
public static Credential getCredentials(String authorizationCode, String state)
throws CodeExchangeException, NoRefreshTokenException, IOException {
String userId = "";
try {
Credential credentials = exchangeCode(authorizationCode);
Userinfo userInfo = getUserInfo(credentials);
userId = userInfo.getId();
if (credentials.getRefreshToken() != null) {
storeCredentials(userId, credentials);
return credentials;
} else {
credentials = getStoredCredentials(userId);
if (credentials != null && credentials.getRefreshToken() != null) {
return credentials;
}
}
} catch (CodeExchangeException e) {
e.printStackTrace();
// Glass services should try to retrieve the user and credentials for the current
// session.
// If none is available, redirect the user to the authorization URL.
e.setAuthorizationUrl(getAuthorizationUrl(userId, state));
throw e;
} catch (NoUserIdException e) {
e.printStackTrace();
}
// No refresh token has been retrieved.
String authorizationUrl = getAuthorizationUrl(userId, state);
throw new NoRefreshTokenException(authorizationUrl);
}
}
Python
将 CLIENTSECRETS_LOCATION 值替换为 client_secrets.json 文件的位置。
import logging
from oauth2client.client import flow_from_clientsecrets
from oauth2client.client import FlowExchangeError
from apiclient.discovery import build
# ...
# Path to client_secrets.json which should contain a JSON document such as:
# {
# "web": {
# "client_id": "[[YOUR_CLIENT_ID]]",
# "client_secret": "[[YOUR_CLIENT_SECRET]]",
# "redirect_uris": [],
# "auth_uri": "https://accounts.google.com/o/oauth2/auth",
# "token_uri": "https://accounts.google.com/o/oauth2/token"
# }
# }
CLIENTSECRETS_LOCATION = '<PATH/TO/CLIENT_SECRETS.JSON>'
REDIRECT_URI = '<YOUR_REGISTERED_REDIRECT_URI>'
SCOPES = [
'https://www.googleapis.com/auth/glass.timeline',
'https://www.googleapis.com/auth/userinfo.profile',
# Add other requested scopes.
]
class GetCredentialsException(Exception):
"""Error raised when an error occurred while retrieving credentials.
Attributes:
authorization_url: Authorization URL to redirect the user to in order to
request offline access.
"""
def __init__(self, authorization_url):
"""Construct a GetCredentialsException."""
self.authorization_url = authorization_url
class CodeExchangeException(GetCredentialsException):
"""Error raised when a code exchange has failed."""
class NoRefreshTokenException(GetCredentialsException):
"""Error raised when no refresh token has been found."""
class NoUserIdException(Exception):
"""Error raised when no user ID could be retrieved."""
def get_stored_credentials(user_id):
"""Retrieved stored credentials for the provided user ID.
Args:
user_id: User's ID.
Returns:
Stored oauth2client.client.OAuth2Credentials if found, None otherwise.
Raises:
NotImplemented: This function has not been implemented.
"""
# TODO: Implement this function to work with your database.
# To instantiate an OAuth2Credentials instance from a Json
# representation, use the oauth2client.client.Credentials.new_from_json
# class method.
raise NotImplementedError()
def store_credentials(user_id, credentials):
"""Store OAuth 2.0 credentials in the application's database.
This function stores the provided OAuth 2.0 credentials using the user ID as
key.
Args:
user_id: User's ID.
credentials: OAuth 2.0 credentials to store.
Raises:
NotImplemented: This function has not been implemented.
"""
# TODO: Implement this function to work with your database.
# To retrieve a Json representation of the credentials instance, call the
# credentials.to_json() method.
raise NotImplementedError()
def exchange_code(authorization_code):
"""Exchange an authorization code for OAuth 2.0 credentials.
Args:
authorization_code: Authorization code to exchange for OAuth 2.0
credentials.
Returns:
oauth2client.client.OAuth2Credentials instance.
Raises:
CodeExchangeException: an error occurred.
"""
flow = flow_from_clientsecrets(CLIENTSECRETS_LOCATION, ' '.join(SCOPES))
flow.redirect_uri = REDIRECT_URI
try:
credentials = flow.step2_exchange(authorization_code)
return credentials
except FlowExchangeError, error:
logging.error('An error occurred: %s', error)
raise CodeExchangeException(None)
def get_user_info(credentials):
"""Send a request to the UserInfo API to retrieve the user's information.
Args:
credentials: oauth2client.client.OAuth2Credentials instance to authorize the
request.
Returns:
User information as a dict.
"""
user_info_service = build(
serviceName='oauth2', version='v2',
http=credentials.authorize(httplib2.Http()))
user_info = None
try:
user_info = user_info_service.userinfo().get().execute()
except errors.HttpError, e:
logging.error('An error occurred: %s', e)
if user_info and user_info.get('id'):
return user_info
else:
raise NoUserIdException()
def get_authorization_url(user_id, state):
"""Retrieve the authorization URL.
Args:
user_id: User's Google ID.
state: State for the authorization URL.
Returns:
Authorization URL to redirect the user to.
"""
flow = flow_from_clientsecrets(CLIENTSECRETS_LOCATION, ' '.join(SCOPES))
flow.params['access_type'] = 'offline'
flow.params['approval_prompt'] = 'force'
flow.params['user_id'] = user_id
flow.params['state'] = state
return flow.step1_get_authorize_url(REDIRECT_URI)
def get_credentials(authorization_code, state):
"""Retrieve credentials using the provided authorization code.
This function exchanges the authorization code for an access token and queries
the UserInfo API to retrieve the user's Google ID.
If a refresh token has been retrieved along with an access token, it is stored
in the application database using the user's Google ID as key.
If no refresh token has been retrieved, the function checks in the application
database for one and returns it if found or raises a NoRefreshTokenException
with the authorization URL to redirect the user to.
Args:
authorization_code: Authorization code to use to retrieve an access token.
state: State to set to the authorization URL in case of error.
Returns:
oauth2client.client.OAuth2Credentials instance containing an access and
refresh token.
Raises:
CodeExchangeError: Could not exchange the authorization code.
NoRefreshTokenException: No refresh token could be retrieved from the
available sources.
"""
user_id = ''
try:
credentials = exchange_code(authorization_code)
user_info = get_user_info(credentials)
user_id = user_info.get('id')
if credentials.refresh_token is not None:
store_credentials(user_id, credentials)
return credentials
else:
credentials = get_stored_credentials(user_id)
if credentials and credentials.refresh_token is not None:
return credentials
except CodeExchangeException, error:
logging.error('An error occurred during code exchange.')
# Glass services should try to retrieve the user and credentials for the current
# session.
# If none is available, redirect the user to the authorization URL.
error.authorization_url = get_authorization_url(user_id, state)
raise error
except NoUserIdException:
logging.error('No user ID could be retrieved.')
# No refresh token has been retrieved.
authorization_url = get_authorization_url(user_id, state)
raise NoRefreshTokenException(authorization_url)
PHP
getCredentials 函数会从提供的授权代码开始检索 OAuth 2.0 凭据。如果无法检索刷新令牌，则会引发异常以及授权网址将用户重定向到以便请求离线访问。
<?php
require_once 'google-api-php-client/src/Google_Client.php';
require_once "google-api-php-client/src/contrib/Google_Oauth2Service.php";
session_start();
// ...
$CLIENT_ID = '<YOUR_CLIENT_ID>';
$CLIENT_SECRET = '<YOUR_CLIENT_SECRET>';
$REDIRECT_URI = '<YOUR_REGISTERED_REDIRECT_URI>';
$SCOPES = array(
'https://www.googleapis.com/auth/glass.timeline',
'https://www.googleapis.com/auth/userinfo.profile');
/**
* Exception thrown when an error occurred while retrieving credentials.
*/
class GetCredentialsException extends Exception {
protected $authorizationUrl;
/**
* Construct a GetCredentialsException.
*
* @param authorizationUrl The authorization URL to redirect the user to.
*/
public function __construct($authorizationUrl) {
$this->authorizationUrl = $authorizationUrl;
}
/**
* @return the authorizationUrl.
*/
public function getAuthorizationUrl() {
return $this->authorizationUrl;
}
/**
* Set the authorization URL.
*/
public function setAuthorizationurl($authorizationUrl) {
$this->authorizationUrl = $authorizationUrl;
}
}
/**
* Exception thrown when no refresh token has been found.
*/
class NoRefreshTokenException extends GetCredentialsException {}
/**
* Exception thrown when a code exchange has failed.
*/
class CodeExchangeException extends GetCredentialsException {}
/**
* Exception thrown when no user ID could be retrieved.
*/
class NoUserIdException extends Exception {}
/**
* Retrieved stored credentials for the provided user ID.
*
* @param String $userId User's ID.
* @return String Json representation of the OAuth 2.0 credentials.
*/
function getStoredCredentials($userId) {
// TODO: Implement this function to work with your database.
throw new RuntimeException('Not implemented!');
}
/**
* Store OAuth 2.0 credentials in the application's database.
*
* @param String $userId User's ID.
* @param String $credentials Json representation of the OAuth 2.0 credentials to
store.
*/
function storeCredentials($userId, $credentials) {
// TODO: Implement this function to work with your database.
throw new RuntimeException('Not implemented!');
}
/**
* Exchange an authorization code for OAuth 2.0 credentials.
*
* @param String $authorizationCode Authorization code to exchange for OAuth 2.0
* credentials.
* @return String Json representation of the OAuth 2.0 credentials.
* @throws CodeExchangeException An error occurred.
*/
function exchangeCode($authorizationCode) {
try {
global $CLIENT_ID, $CLIENT_SECRET, $REDIRECT_URI;
$client = new Google_Client();
$client->setClientId($CLIENT_ID);
$client->setClientSecret($CLIENT_SECRET);
$client->setRedirectUri($REDIRECT_URI);
$_GET['code'] = $authorizationCode;
return $client->authenticate();
} catch (Google_AuthException $e) {
print 'An error occurred: ' . $e->getMessage();
throw new CodeExchangeException(null);
}
}
/**
* Send a request to the UserInfo API to retrieve the user's information.
*
* @param String credentials OAuth 2.0 credentials to authorize the request.
* @return Userinfo User's information.
* @throws NoUserIdException An error occurred.
*/
function getUserInfo($credentials) {
$apiClient = new Google_Client();
$apiClient->setUseObjects(true);
$apiClient->setAccessToken($credentials);
$userInfoService = new Google_Oauth2Service($apiClient);
$userInfo = null;
try {
$userInfo = $userInfoService->userinfo->get();
} catch (Google_Exception $e) {
print 'An error occurred: ' . $e->getMessage();
}
if ($userInfo != null && $userInfo->getId() != null) {
return $userInfo;
} else {
throw new NoUserIdException();
}
}
/**
* Retrieve the authorization URL.
*
* @param String $userId User's Google ID.
* @param String $state State for the authorization URL.
* @return String Authorization URL to redirect the user to.
*/
function getAuthorizationUrl($userId, $state) {
global $CLIENT_ID, $REDIRECT_URI, $SCOPES;
$client = new Google_Client();
$client->setClientId($CLIENT_ID);
$client->setRedirectUri($REDIRECT_URI);
$client->setAccessType('offline');
$client->setApprovalPrompt('force');
$client->setState($state);
$client->setScopes($SCOPES);
$tmpUrl = parse_url($client->createAuthUrl());
$query = explode('&', $tmpUrl['query']);
$query[] = 'user_id=' . urlencode($userId);
return
$tmpUrl['scheme'] . '://' . $tmpUrl['host'] . $tmpUrl['port'] .
$tmpUrl['path'] . '?' . implode('&', $query);
}
/**
* Retrieve credentials using the provided authorization code.
*
* This function exchanges the authorization code for an access token and
* queries the UserInfo API to retrieve the user's Google ID. If a
* refresh token has been retrieved along with an access token, it is stored
* in the application database using the user's Google ID as key. If no
* refresh token has been retrieved, the function checks in the application
* database for one and returns it if found or throws a NoRefreshTokenException
* with the authorization URL to redirect the user to.
*
* @param String authorizationCode Authorization code to use to retrieve an access
* token.
* @param String state State to set to the authorization URL in case of error.
* @return String Json representation of the OAuth 2.0 credentials.
* @throws NoRefreshTokenException No refresh token could be retrieved from
* the available sources.
*/
function getCredentials($authorizationCode, $state) {
$userId = '';
try {
$credentials = exchangeCode($authorizationCode);
$userInfo = getUserInfo($credentials);
$userId = $userInfo->getId();
$credentialsArray = json_decode($credentials, true);
if (isset($credentialsArray['refresh_token'])) {
storeCredentials($userId, $credentials);
return $credentials;
} else {
$credentials = getStoredCredentials($userId);
$credentialsArray = json_decode($credentials, true);
if ($credentials != null &&
isset($credentialsArray['refresh_token'])) {
return $credentials;
}
}
} catch (CodeExchangeException $e) {
print 'An error occurred during code exchange.';
// Glass services should try to retrieve the user and credentials for the current
// session.
// If none is available, redirect the user to the authorization URL.
$e->setAuthorizationUrl(getAuthorizationUrl($userId, $state));
throw $e;
} catch (NoUserIdException $e) {
print 'No user ID could be retrieved.';
}
// No refresh token has been retrieved.
$authorizationUrl = getAuthorizationUrl($userId, $state);
throw new NoRefreshTokenException($authorizationUrl);
}
?>
.NET
GetCredentials 函数会从提供的授权代码开始检索 OAuth 2.0 凭据。如果无法检索刷新令牌，则会引发异常以及授权网址将用户重定向到以便请求离线访问。
using DotNetOpenAuth.Messaging;
using DotNetOpenAuth.OAuth2;
using Google;
using Google.Apis.Authentication;
using Google.Apis.Authentication.OAuth2;
using Google.Apis.Authentication.OAuth2.DotNetOpenAuth;
using Google.Apis.Oauth2.v2;
using Google.Apis.Oauth2.v2.Data;
using Google.Apis.Services;
using System;
using System.Collections.Specialized;
using System.Web;
// ...
class MyClass {
static String CLIENT_ID = "<YOUR_CLIENT_ID>";
static String CLIENT_SECRET = "<YOUR_CLIENT_SECRET>";
static String REDIRECT_URI = "<YOUR_REGISTERED_REDIRECT_URI>";
static String[] SCOPES = new String[] {
"https://www.googleapis.com/auth/glass.timeline",
"https://www.googleapis.com/auth/userinfo.profile"
};
/// <summary>
/// Exception thrown when an error occurred while retrieving credentials.
/// </summary>
public class GetCredentialsException : Exception {
public String AuthorizationUrl { get; set; }
/// <summary>
/// Construct a GetCredentialsException.
/// </summary>
/// @param authorizationUrl The authorization URL to redirect the user to.
public GetCredentialsException(String authorizationUrl) {
this.AuthorizationUrl = authorizationUrl;
}
}
/// <summary>
/// Exception thrown when no refresh token has been found.
/// </summary>
public class NoRefreshTokenException : GetCredentialsException {
/// <summary>
/// Construct a NoRefreshTokenException.
/// </summary>
/// @param authorizationUrl The authorization URL to redirect the user to.
public NoRefreshTokenException(String authorizationUrl) : base(authorizationUrl) {
}
}
/// <summary>
/// Exception thrown when a code exchange has failed.
/// </summary>
private class CodeExchangeException : GetCredentialsException {
/// <summary>
/// Construct a CodeExchangeException.
/// </summary>
/// @param authorizationUrl The authorization URL to redirect the user to.
public CodeExchangeException(String authorizationUrl) : base(authorizationUrl) {
}
}
/// <summary>
/// Exception thrown when no user ID could be retrieved.
/// </summary>
private class NoUserIdException : Exception {
}
/// <summary>
/// Extends the NativeApplicationClient class to allow setting of a custom IAuthorizationState.
/// </summary>
public class StoredStateClient : NativeApplicationClient {
/// <summary>
/// Initializes a new instance of the <see cref="StoredStateClient"/> class.
/// </summary>
/// <param name="authorizationServer">The token issuer.</param>
/// <param name="clientIdentifier">The client identifier.</param>
/// <param name="clientSecret">The client secret.</param>
public StoredStateClient(AuthorizationServerDescription authorizationServer,
String clientIdentifier,
String clientSecret,
IAuthorizationState state)
: base(authorizationServer, clientIdentifier, clientSecret) {
this.State = state;
}
public IAuthorizationState State { get; private set; }
/// <summary>
/// Returns the IAuthorizationState stored in the StoredStateClient instance.
/// </summary>
/// <param name="provider">OAuth2 client.</param>
/// <returns>The stored authorization state.</returns>
static public IAuthorizationState GetState(StoredStateClient provider) {
return provider.State;
}
}
/// <summary>
/// Retrieve an IAuthenticator instance using the provided state.
/// </summary>
/// <param name="credentials">OAuth 2.0 credentials to use.</param>
/// <returns>Authenticator using the provided OAuth 2.0 credentials</returns>
public static IAuthenticator GetAuthenticatorFromState(IAuthorizationState credentials) {
var provider = new StoredStateClient(GoogleAuthenticationServer.Description, CLIENT_ID, CLIENT_SECRET, credentials);
var auth = new OAuth2Authenticator<StoredStateClient>(provider, StoredStateClient.GetState);
auth.LoadAccessToken();
return auth;
}
/// <summary>
/// Retrieved stored credentials for the provided user ID.
/// </summary>
/// <param name="userId">User's ID.</param>
/// <returns>Stored GoogleAccessProtectedResource if found, null otherwise.</returns>
static IAuthorizationState GetStoredCredentials(String userId) {
// TODO: Implement this method to work with your database.
throw new NotImplementedException();
}
/// <summary>
/// Store OAuth 2.0 credentials in the application's database.
/// </summary>
/// <param name="userId">User's ID.</param>
/// <param name="credentials">The OAuth 2.0 credentials to store.</param>
static void StoreCredentials(String userId, IAuthorizationState credentials) {
// TODO: Implement this method to work with your database.
throw new NotImplementedException();
}
/// <summary>
/// Exchange an authorization code for OAuth 2.0 credentials.
/// </summary>
/// <param name="authorizationCode">Authorization code to exchange for OAuth 2.0 credentials.</param>
/// <returns>OAuth 2.0 credentials.</returns>
/// <exception cref="CodeExchangeException">An error occurred.</exception>
static IAuthorizationState ExchangeCode(String authorizationCode) {
var provider = new NativeApplicationClient(GoogleAuthenticationServer.Description, CLIENT_ID, CLIENT_SECRET);
IAuthorizationState state = new AuthorizationState();
state.Callback = new Uri(REDIRECT_URI);
try {
state = provider.ProcessUserAuthorization(authorizationCode, state);
return state;
} catch (ProtocolException) {
throw new CodeExchangeException(null);
}
}
/// <summary>
/// Send a request to the UserInfo API to retrieve the user's information.
/// </summary>
/// <param name="credentials">OAuth 2.0 credentials to authorize the request.</param>
/// <returns>User's information.</returns>
/// <exception cref="NoUserIdException">An error occurred.</exception>
static Userinfo GetUserInfo(IAuthorizationState credentials) {
Oauth2Service userInfoService = new Oauth2Service(new BaseClientService.Initializer()
{
Authenticator = GetAuthenticatorFromState(credentials)
});
Userinfo userInfo = null;
try {
userInfo = userInfoService.Userinfo.Get().Fetch();
} catch (GoogleApiRequestException e) {
Console.WriteLine("An error occurred: " + e.Message);
}
if (userInfo != null && !String.IsNullOrEmpty(userInfo.Id)) {
return userInfo;
} else {
throw new NoUserIdException();
}
}
/// <summary>
/// Retrieve the authorization URL.
/// </summary>
/// <param name="userId">User's Google ID.</param>
/// <param name="state">State for the authorization URL.</param>
/// <returns>Authorization URL to redirect the user to.</returns>
public static String GetAuthorizationUrl(String userId, String state) {
var provider = new NativeApplicationClient(GoogleAuthenticationServer.Description);
provider.ClientIdentifier = CLIENT_ID;
IAuthorizationState authorizationState = new AuthorizationState(SCOPES);
authorizationState.Callback = new Uri(REDIRECT_URI);
UriBuilder builder = new UriBuilder(provider.RequestUserAuthorization(authorizationState));
NameValueCollection queryParameters = HttpUtility.ParseQueryString(builder.Query);
queryParameters.Set("access_type", "offline");
queryParameters.Set("approval_prompt", "force");
queryParameters.Set("user_id", userId);
queryParameters.Set("state", state);
builder.Query = queryParameters.ToString();
return builder.Uri.ToString();
}
/// <summary>
/// Retrieve credentials using the provided authorization code.
///
/// This function exchanges the authorization code for an access token and
/// queries the UserInfo API to retrieve the user's Google ID. If a
/// refresh token has been retrieved along with an access token, it is stored
/// in the application database using the user's Google ID as key. If no
/// refresh token has been retrieved, the function checks in the application
/// database for one and returns it if found or throws a NoRefreshTokenException
/// with the authorization URL to redirect the user to.
/// </summary>
/// <param name="authorizationCode">Authorization code to use to retrieve an access token.</param>
/// <param name="state">State to set to the authorization URL in case of error.</param>
/// <returns>OAuth 2.0 credentials instance containing an access and refresh token.</returns>
/// <exception cref="CodeExchangeException">
/// An error occurred while exchanging the authorization code.
/// </exception>
/// <exception cref="NoRefreshTokenException">
/// No refresh token could be retrieved from the available sources.
/// </exception>
public static IAuthenticator GetCredentials(String authorizationCode, String state) {
String userId = "";
try {
IAuthorizationState credentials = ExchangeCode(authorizationCode);
Userinfo userInfo = GetUserInfo(credentials);
userId = userInfo.Id;
if (!String.IsNullOrEmpty(credentials.RefreshToken)) {
StoreCredentials(userId, credentials);
return GetAuthenticatorFromState(credentials);
} else {
credentials = GetStoredCredentials(userId);
if (credentials != null && !String.IsNullOrEmpty(credentials.RefreshToken)) {
return GetAuthenticatorFromState(credentials);
}
}
} catch (CodeExchangeException e) {
Console.WriteLine("An error occurred during code exchange.");
// Glass services should try to retrieve the user and credentials for the current
// session.
// If none is available, redirect the user to the authorization URL.
e.AuthorizationUrl = GetAuthorizationUrl(userId, state);
throw e;
} catch (NoUserIdException) {
Console.WriteLine("No user ID could be retrieved.");
}
// No refresh token has been retrieved.
String authorizationUrl = GetAuthorizationUrl(userId, state);
throw new NoRefreshTokenException(authorizationUrl);
}
}
Ruby
get_credentials 函数会从提供的授权代码开始检索 OAuth 2.0 凭据。如果无法检索刷新令牌，则会引发异常以及授权网址将用户重定向到以便请求离线访问。
require 'google/api_client'
CLIENT_ID = '<YOUR_CLIENT_ID>'
CLIENT_SECRET = '<YOUR_CLIENT_SECRET>'
REDIRECT_URI = '<YOUR_REGISTERED_REDIRECT_URI>'
SCOPES = [
'https://www.googleapis.com/auth/glass.timeline',
'https://www.googleapis.com/auth/userinfo.profile',
# Add other requested scopes.
]
##
# Error raised when an error occurred while retrieving credentials.
class GetCredentialsError < StandardError
##
# Initialize a NoRefreshTokenError instance.
#
# @param [String] authorize_url
# Authorization URL to redirect the user to in order to in order to request
# offline access.
def initialize(authorization_url)
@authorization_url = authorization_url
end
def authorization_url=(authorization_url)
@authorization_url = authorization_url
end
def authorization_url
return @authorization_url
end
end
##
# Error raised when a code exchange has failed.
class CodeExchangeError < GetCredentialsError
end
##
# Error raised when no refresh token has been found.
class NoRefreshTokenError < GetCredentialsError
end
##
# Error raised when no user ID could be retrieved.
class NoUserIdError < StandardError
end
##
# Retrieved stored credentials for the provided user ID.
#
# @param [String] user_id
# User's ID.
# @return [Signet::OAuth2::Client]
# Stored OAuth 2.0 credentials if found, nil otherwise.
def get_stored_credentials(user_id)
raise NotImplementedError, 'get_stored_credentials is not implemented.'
end
##
# Store OAuth 2.0 credentials in the application's database.
#
# @param [String] user_id
# User's ID.
# @param [Signet::OAuth2::Client] credentials
# OAuth 2.0 credentials to store.
def store_credentials(user_id, credentials)
raise NotImplementedError, 'store_credentials is not implemented.'
end
##
# Exchange an authorization code for OAuth 2.0 credentials.
#
# @param [String] auth_code
# Authorization code to exchange for OAuth 2.0 credentials.
# @return [Signet::OAuth2::Client]
# OAuth 2.0 credentials.
def exchange_code(authorization_code)
client = Google::APIClient.new
client.authorization.client_id = CLIENT_ID
client.authorization.client_secret = CLIENT_SECRET
client.authorization.code = authorization_code
client.authorization.redirect_uri = REDIRECT_URI
begin
client.authorization.fetch_access_token!
return client.authorization
rescue Signet::AuthorizationError
raise CodeExchangeError.new(nil)
end
end
##
# Send a request to the UserInfo API to retrieve the user's information.
#
# @param [Signet::OAuth2::Client] credentials
# OAuth 2.0 credentials to authorize the request.
# @return [Google::APIClient::Schema::Oauth2::V2::Userinfo]
# User's information.
def get_user_info(credentials)
client = Google::APIClient.new
client.authorization = credentials
oauth2 = client.discovered_api('oauth2', 'v2')
result = client.execute!(:api_method => oauth2.userinfo.get)
user_info = nil
if result.status == 200
user_info = result.data
else
puts "An error occurred: #{result.data['error']['message']}"
end
if user_info != nil && user_info.id != nil
return user_info
end
raise NoUserIdError, "Unable to retrieve the user's Google ID."
end
##
# Retrieve authorization URL.
#
# @param [String] user_id
# User's Google ID.
# @param [String] state
# State for the authorization URL.
# @return [String]
# Authorization URL to redirect the user to.
def get_authorization_url(user_id, state)
client = Google::APIClient.new
client.authorization.client_id = CLIENT_ID
client.authorization.redirect_uri = REDIRECT_URI
client.authorization.scope = SCOPES
return client.authorization.authorization_uri(
:options => {
:approval_prompt => :force,
:access_type => :offline,
:user_id => user_id,
:state => state
}).to_s
end
##
# Retrieve credentials using the provided authorization code.
#
# This function exchanges the authorization code for an access token and queries
# the UserInfo API to retrieve the user's Google ID.
# If a refresh token has been retrieved along with an access token, it is stored
# in the application database using the user's Google ID as key.
# If no refresh token has been retrieved, the function checks in the application
# database for one and returns it if found or raises a NoRefreshTokenError
# with an authorization URL to redirect the user to.
#
# @param [String] auth_code
# Authorization code to use to retrieve an access token.
# @param [String] state
# State to set to the authorization URL in case of error.
# @return [Signet::OAuth2::Client]
# OAuth 2.0 credentials containing an access and refresh token.
def get_credentials(authorization_code, state)
user_id = ''
begin
credentials = exchange_code(authorization_code)
user_info = get_user_info(credentials)
user_id = user_info.id
if credentials.refresh_token != nil
store_credentials(user_id, credentials)
return credentials
else
credentials = get_stored_credentials(user_id)
if credentials != nil && credentials.refresh_token != nil
return credentials
end
end
rescue CodeExchangeError => error
print 'An error occurred during code exchange.'
# Glass services should try to retrieve the user and credentials for the current
# session.
# If none is available, redirect the user to the authorization URL.
error.authorization_url = get_authorization_url(user_id, state)
raise error
rescue NoUserIdError
print 'No user ID could be retrieved.'
end
authorization_url = get_authorization_url(user_id, state)
raise NoRefreshTokenError.new(authorization_url)
end
使用存储的凭据进行授权
用户首次授权流程成功后访问您的应用时，您的应用可以使用存储的刷新令牌向请求授权，而无需提示最终用户。
如果您已对用户进行身份验证，您的应用可以从其数据库中检索刷新令牌，并将该令牌存储在服务器端会话中。如果刷新令牌被撤消或无效，您需要捕获此令牌并采取相应措施。
使用 OAuth 2.0 凭据
如上一部分所示，检索到 OAuth 2.0 凭据后，可以使用这些凭据向 Google 镜像 API 服务对象授权并向 API 发送请求。
以下代码段展示了如何实例化 Google 镜像 API 服务对象并向其授权，并向 Google 镜像 API 发送请求，以检索 timeline item 的元数据。
实例化服务对象
此代码示例展示了如何实例化服务对象，然后授权它发出 API 请求。
Java
import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.jackson.JacksonFactory;
import com.google.api.services.mirror.Mirror;
// ...
public class MyClass {
// ...
/**
* Build a Mirror service object.
*
* @param credentials OAuth 2.0 credentials.
* @return Mirror service object.
*/
static Mirror buildService(GoogleCredential credentials) {
HttpTransport httpTransport = new NetHttpTransport();
JacksonFactory jsonFactory = new JacksonFactory();
return new Mirror.Builder(httpTransport, jsonFactory, credentials)
.build();
}
// ...
}
Python
from apiclient.discovery import build
# ...
def build_service(credentials):
"""Build a Mirror service object.
Args:
credentials: OAuth 2.0 credentials.
Returns:
Mirror service object.
"""
http = httplib2.Http()
http = credentials.authorize(http)
return build('mirror', 'v1', http=http)
PHP
<?php
session_start();
require_once "google-api-php-client/src/Google_Client.php";
require_once "google-api-php-client/src/contrib/Google_MirrorService.php";
// ...
/**
* Build a Mirror service object.
*
* @param String credentials Json representation of the OAuth 2.0 credentials.
* @return Google_MirrorService service object.
*/
function buildService($credentials) {
$apiClient = new Google_Client();
$apiClient->setUseObjects(true);
$apiClient->setAccessToken($credentials);
return new Google_MirrorService($apiClient);
}
// ...
?>
.NET
using Google.Apis.Authentication;
using Google.Apis.Mirror.v1;
using Google.Apis.Services;
// ...
public class MyClass {
// ...
/// <summary>
/// Build a Mirror service object.
/// </summary>
/// <param name="credentials">OAuth 2.0 credentials.</param>
/// <returns>Mirror service object.</returns>
static MirrorService BuildService(IAuthenticator credentials) {
return new MirrorService(new BaseClientService.Initializer()
{
Authenticator = credentials
});
}
}
Ruby
require 'google/api_client'
##
# Build a Mirror client instance.
#
# @param [Signet::OAuth2::Client] credentials
# OAuth 2.0 credentials.
# @return [Google::APIClient]
# Client instance
def build_client(credentials)
client = Google::APIClient.new
client.authorization = credentials
client = client.discovered_api('mirror', 'v1')
client
end
发送已授权的请求并检查凭据是否已撤消
以下代码段使用已获授权的 Google 镜像 API 服务实例，向 Google 镜像 API 发送已获授权的 GET 请求，以检索 timeline item 的元数据。
如果发生错误，该代码会检查 HTTP 401 状态代码，并通过将用户重定向到授权网址来处理该状态代码。
Google 参考文档中介绍了更多 Google 镜像 API 操作。
Java
import com.google.api.client.http.HttpResponse;
import com.google.api.client.http.HttpResponseException;
import com.google.api.services.mirror.Mirror;
import com.google.api.services.mirror.model.TimelineItem;
import java.io.IOException;
// ...
public class MyClass {
// ...
/**
* Print a timeline item's metadata.
*
* @param service Mirror service instance.
* @param itemId ID of the timeline item to print metadata for.
*/
static void printTimelineItem(Mirror service, String itemId) {
try {
TimelineItem item = service.timeline().get(itemId).execute();
System.out.println("Text: " + item.getText());
System.out.println("HTML: " + item.getHtml());
} catch (HttpResponseException e) {
if (e.getStatusCode() == 401) {
// Credentials have been revoked.
// TODO: Redirect the user to the authorization URL and/or
// remove the credentials from the database.
throw new UnsupportedOperationException();
}
} catch (IOException e) {
System.out.println("An error occurred: " + e);
}
}
// ...
}
Python
from apiclient import errors
# ...
def print_timeline_item(service, item_id):
"""Print a timeline item's metadata.
Args:
service: Mirror service instance.
item_id: ID of the timeline item to print metadata for.
"""
try:
item = service.timeline().get(id=item_id).execute()
print 'Text: %s' % item['text']
print 'HTML: %s' % item['html']
except errors.HttpError, error:
if error.resp.status == 401:
# Credentials have been revoked.
# TODO: Redirect the user to the authorization URL and/or remove
# the credentials from the database.
raise NotImplementedError()
PHP
/**
* Print a timeline item's metadata.
*
* @param Google_MirrorService $service Mirror service instance.
* @param string $itemId ID of the timeline item to print metadata for.
*/
function printTimelineItem($service, $itemId) {
try {
$item = $service->timeline->get($itemId);
print "Text: " . $item->getText() . "\n";
print "HTML: " . $item->getHtml() . "\n";
} catch (apiAuthException) {
// Credentials have been revoked.
// TODO: Redirect the user to the authorization URL and/or remove
// the credentials from the database.
throw new RuntimeException('Not implemented!');
} catch (apiException $e) {
print "An error occurred: " . $e->getMessage();
}
}
.NET
using Google;
using Google.Apis.Mirror.v1;
using Google.Apis.Mirror.v1.Data;
using System;
using System.Net;
// ...
public class MyClass {
// ...
/// <summary>
/// Print a timeline item's metadata.
/// </summary>
/// <param name="service">Mirror service instance.</param>
/// <param name="itemId">ID of the timeline item to print metadata for.</param>
private static void printTimelineItem(MirrorService service, String itemId) {
try {
TimelineItem item = service.Timeline.Get(itemId).Fetch();
Console.WriteLine("Text: " + item.Text);
Console.WriteLine("HTML: " + item.Html);
} catch (GoogleApiRequestException e) {
if (e.HttpStatusCode == HttpStatusCode.Unauthorized) {
// Credentials have been revoked.
// TODO: Redirect the user to the authorization URL and/or remove the
// credentials from the database.
throw new NotImplementedException();
}
}
}
//...
}
Ruby
require 'google/api_client'
##
# Print a timeline item's metadata.
#
# @param [Google::APIClient] client
# Authorized client instance
# @param [String] item_id
# ID of timeline item to print
# @return nil
def print_timeline_item(client, item_id)
mirror = client.discovered_api('mirror', 'v1')
result = client.execute(
:api_method => mirror.timeline.get,
:parameters => { 'id' => item_id })
if result.success?
item = result.data
puts "Text: #{item.text}"
puts "Html: #{item.html}"
elseif result.status == 401
# Credentials have been revoked.
# TODO: Redirect the user to the authorization URL and/or remove
# the credentials from the database.
raise NotImplementedError, 'Redirect the user.'
end
else
puts "An error occurred: #{result.data['error']['message']}"
end
end