<?php
/*
* Copyright 2015 Google Inc.
*
* 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.
*/
namespace Google\Auth\Credentials;
use Google\Auth\CredentialsLoader;
use Google\Auth\GetQuotaProjectInterface;
use Google\Auth\OAuth2;
use Google\Auth\ProjectIdProviderInterface;
use Google\Auth\ServiceAccountSignerTrait;
use Google\Auth\SignBlobInterface;
use InvalidArgumentException;
/**
* ServiceAccountCredentials supports authorization using a Google service
* account.
*
* (cf https://developers.google.com/accounts/docs/OAuth2ServiceAccount)
*
* It's initialized using the json key file that's downloadable from developer
* console, which should contain a private_key and client_email fields that it
* uses.
*
* Use it with AuthTokenMiddleware to authorize http requests:
*
* use Google\Auth\Credentials\ServiceAccountCredentials;
* use Google\Auth\Middleware\AuthTokenMiddleware;
* use GuzzleHttp\Client;
* use GuzzleHttp\HandlerStack;
*
* $sa = new ServiceAccountCredentials(
* 'https://www.googleapis.com/auth/taskqueue',
* '/path/to/your/json/key_file.json'
* );
* $middleware = new AuthTokenMiddleware($sa);
* $stack = HandlerStack::create();
* $stack->push($middleware);
*
* $client = new Client([
* 'handler' => $stack,
* 'base_uri' => 'https://www.googleapis.com/taskqueue/v1beta2/projects/',
* 'auth' => 'google_auth' // authorize all requests
* ]);
*
* $res = $client->get('myproject/taskqueues/myqueue');
*/
class ServiceAccountCredentials extends CredentialsLoader implements
GetQuotaProjectInterface,
SignBlobInterface,
ProjectIdProviderInterface
{
use ServiceAccountSignerTrait;
/**
* The OAuth2 instance used to conduct authorization.
*
* @var OAuth2
*/
protected $auth;
/**
* The quota project associated with the JSON credentials
*
* @var string
*/
protected $quotaProject;
/*
* @var string|null
*/
protected $projectId;
/*
* @var array|null
*/
private $lastReceivedJwtAccessToken;
/*
* @var bool
*/
private $useJwtAccessWithScope = false;
/*
* @var ServiceAccountJwtAccessCredentials|null
*/
private $jwtAccessCredentials;
/**
* Create a new ServiceAccountCredentials.
*
* @param string|array $scope the scope of the access request, expressed
* either as an Array or as a space-delimited String.
* @param string|array $jsonKey JSON credential file path or JSON credentials
* as an associative array
* @param string $sub an email address account to impersonate, in situations when
* the service account has been delegated domain wide access.
* @param string $targetAudience The audience for the ID token.
*/
public function __construct(
$scope,
$jsonKey,
$sub = null,
$targetAudience = null
) {
if (is_string($jsonKey)) {
if (!file_exists($jsonKey)) {
throw new \InvalidArgumentException('file does not exist');
}
$jsonKeyStream = file_get_contents($jsonKey);
if (!$jsonKey = json_decode($jsonKeyStream, true)) {
throw new \LogicException('invalid json for auth config');
}
}
if (!array_key_exists('client_email', $jsonKey)) {
throw new \InvalidArgumentException(
'json key is missing the client_email field'
);
}
if (!array_key_exists('private_key', $jsonKey)) {
throw new \InvalidArgumentException(
'json key is missing the private_key field'
);
}
if (array_key_exists('quota_project_id', $jsonKey)) {
$this->quotaProject = (string) $jsonKey['quota_project_id'];
}
if ($scope && $targetAudience) {
throw new InvalidArgumentException(
'Scope and targetAudience cannot both be supplied'
);
}
$additionalClaims = [];
if ($targetAudience) {
$additionalClaims = ['target_audience' => $targetAudience];
}
$this->auth = new OAuth2([
'audience' => self::TOKEN_CREDENTIAL_URI,
'issuer' => $jsonKey['client_email'],
'scope' => $scope,
'signingAlgorithm' => 'RS256',
'signingKey' => $jsonKey['private_key'],
'sub' => $sub,
'tokenCredentialUri' => self::TOKEN_CREDENTIAL_URI,
'additionalClaims' => $additionalClaims,
]);
$this->projectId = isset($jsonKey['project_id'])
? $jsonKey['project_id']
: null;
}
/**
* When called, the ServiceAccountCredentials will use an instance of
* ServiceAccountJwtAccessCredentials to fetch (self-sign) an access token
* even when only scopes are supplied. Otherwise,
* ServiceAccountJwtAccessCredentials is only called when no scopes and an
* authUrl (audience) is suppled.
*/
public function useJwtAccessWithScope()
{
$this->useJwtAccessWithScope = true;
}
/**
* @param callable $httpHandler
*
* @return array A set of auth related metadata, containing the following
* keys:
* - access_token (string)
* - expires_in (int)
* - token_type (string)
*/
public function fetchAuthToken(callable $httpHandler = null)
{
if ($this->useSelfSignedJwt()) {
$jwtCreds = $this->createJwtAccessCredentials();
$accessToken = $jwtCreds->fetchAuthToken($httpHandler);
if ($lastReceivedToken = $jwtCreds->getLastReceivedToken()) {
// Keep self-signed JWTs in memory as the last received token
$this->lastReceivedJwtAccessToken = $lastReceivedToken;
}
return $accessToken;
}
return $this->auth->fetchAuthToken($httpHandler);
}
/**
* @return string
*/
public function getCacheKey()
{
$key = $this->auth->getIssuer() . ':' . $this->auth->getCacheKey();
if ($sub = $this->auth->getSub()) {
$key .= ':' . $sub;
}
return $key;
}
/**
* @return array
*/
public function getLastReceivedToken()
{
// If self-signed JWTs are being used, fetch the last received token
// from memory. Else, fetch it from OAuth2
return $this->useSelfSignedJwt()
? $this->lastReceivedJwtAccessToken
: $this->auth->getLastReceivedToken();
}
/**
* Get the project ID from the service account keyfile.
*
* Returns null if the project ID does not exist in the keyfile.
*
* @param callable $httpHandler Not used by this credentials type.
* @return string|null
*/
public function getProjectId(callable $httpHandler = null)
{
return $this->projectId;
}
/**
* Updates metadata with the authorization token.
*
* @param array $metadata metadata hashmap
* @param string $authUri optional auth uri
* @param callable $httpHandler callback which delivers psr7 request
* @return array updated metadata hashmap
*/
public function updateMetadata(
$metadata,
$authUri = null,
callable $httpHandler = null
) {
// scope exists. use oauth implementation
if (!$this->useSelfSignedJwt()) {
return parent::updateMetadata($metadata, $authUri, $httpHandler);
}
$jwtCreds = $this->createJwtAccessCredentials();
if ($this->auth->getScope()) {
// Prefer user-provided "scope" to "audience"
$updatedMetadata = $jwtCreds->updateMetadata($metadata, null, $httpHandler);
} else {
$updatedMetadata = $jwtCreds->updateMetadata($metadata, $authUri, $httpHandler);
}
if ($lastReceivedToken = $jwtCreds->getLastReceivedToken()) {
// Keep self-signed JWTs in memory as the last received token
$this->lastReceivedJwtAccessToken = $lastReceivedToken;
}
return $updatedMetadata;
}
private function createJwtAccessCredentials()
{
if (!$this->jwtAccessCredentials) {
// Create credentials for self-signing a JWT (JwtAccess)
$credJson = array(
'private_key' => $this->auth->getSigningKey(),
'client_email' => $this->auth->getIssuer(),
);
$this->jwtAccessCredentials = new ServiceAccountJwtAccessCredentials(
$credJson,
$this->auth->getScope()
);
}
return $this->jwtAccessCredentials;
}
/**
* @param string $sub an email address account to impersonate, in situations when
* the service account has been delegated domain wide access.
*/
public function setSub($sub)
{
$this->auth->setSub($sub);
}
/**
* Get the client name from the keyfile.
*
* In this case, it returns the keyfile's client_email key.
*
* @param callable $httpHandler Not used by this credentials type.
* @return string
*/
public function getClientName(callable $httpHandler = null)
{
return $this->auth->getIssuer();
}
/**
* Get the quota project used for this API request
*
* @return string|null
*/
public function getQuotaProject()
{
return $this->quotaProject;
}
private function useSelfSignedJwt()
{
// If claims are set, this call is for "id_tokens"
if ($this->auth->getAdditionalClaims()) {
return false;
}
// When true, ServiceAccountCredentials will always use JwtAccess for access tokens
if ($this->useJwtAccessWithScope) {
return true;
}
return is_null($this->auth->getScope());
}
}