Viewing file:  ImpersonatedServiceAccountCredentials.php (7.54 KB) -rw-r--r--
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<?php
/*
* Copyright 2022 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\CacheTrait;
use Google\Auth\CredentialsLoader;
use Google\Auth\FetchAuthTokenInterface;
use Google\Auth\HttpHandler\HttpClientCache;
use Google\Auth\HttpHandler\HttpHandlerFactory;
use Google\Auth\IamSignerTrait;
use Google\Auth\SignBlobInterface;
use GuzzleHttp\Psr7\Request;
use InvalidArgumentException;
use LogicException;
class ImpersonatedServiceAccountCredentials extends CredentialsLoader implements SignBlobInterface
{
use CacheTrait;
use IamSignerTrait;
private const CRED_TYPE = 'imp';
/**
* @var string
*/
protected $impersonatedServiceAccountName;
protected FetchAuthTokenInterface $sourceCredentials;
private string $serviceAccountImpersonationUrl;
/**
* @var string[]
*/
private array $delegates;
/**
* @var string|string[]
*/
private string|array $targetScope;
private int $lifetime;
/**
* Instantiate an instance of ImpersonatedServiceAccountCredentials from a credentials file that
* has be created with the --impersonate-service-account flag.
*
* @param string|string[]|null $scope The scope of the access request, expressed either as an
* array or as a space-delimited string.
* @param string|array<mixed> $jsonKey JSON credential file path or JSON array credentials {
* JSON credentials as an associative array.
*
* @type string $service_account_impersonation_url The URL to the service account
* @type string|FetchAuthTokenInterface $source_credentials The source credentials to impersonate
* @type int $lifetime The lifetime of the impersonated credentials
* @type string[] $delegates The delegates to impersonate
* }
*/
public function __construct(
$scope,
$jsonKey
) {
if (is_string($jsonKey)) {
if (!file_exists($jsonKey)) {
throw new InvalidArgumentException('file does not exist');
}
$json = file_get_contents($jsonKey);
if (!$jsonKey = json_decode((string) $json, true)) {
throw new LogicException('invalid json for auth config');
}
}
if (!array_key_exists('service_account_impersonation_url', $jsonKey)) {
throw new LogicException(
'json key is missing the service_account_impersonation_url field'
);
}
if (!array_key_exists('source_credentials', $jsonKey)) {
throw new LogicException('json key is missing the source_credentials field');
}
if (is_array($jsonKey['source_credentials'])) {
if (!array_key_exists('type', $jsonKey['source_credentials'])) {
throw new InvalidArgumentException('json key source credentials are missing the type field');
}
$jsonKey['source_credentials'] = CredentialsLoader::makeCredentials($scope, $jsonKey['source_credentials']);
}
$this->targetScope = $scope ?? [];
$this->lifetime = $jsonKey['lifetime'] ?? 3600;
$this->delegates = $jsonKey['delegates'] ?? [];
$this->serviceAccountImpersonationUrl = $jsonKey['service_account_impersonation_url'];
$this->impersonatedServiceAccountName = $this->getImpersonatedServiceAccountNameFromUrl(
$this->serviceAccountImpersonationUrl
);
$this->sourceCredentials = $jsonKey['source_credentials'];
}
/**
* Helper function for extracting the Server Account Name from the URL saved in the account
* credentials file.
*
* @param $serviceAccountImpersonationUrl string URL from "service_account_impersonation_url"
* @return string Service account email or ID.
*/
private function getImpersonatedServiceAccountNameFromUrl(
string $serviceAccountImpersonationUrl
): string {
$fields = explode('/', $serviceAccountImpersonationUrl);
$lastField = end($fields);
$splitter = explode(':', $lastField);
return $splitter[0];
}
/**
* Get the client name from the keyfile
*
* In this implementation, it will return the issuers email from the oauth token.
*
* @param callable|null $unusedHttpHandler not used by this credentials type.
* @return string Token issuer email
*/
public function getClientName(?callable $unusedHttpHandler = null)
{
return $this->impersonatedServiceAccountName;
}
/**
* @param callable|null $httpHandler
*
* @return array<mixed> {
* A set of auth related metadata, containing the following
*
* @type string $access_token
* @type int $expires_in
* @type string $scope
* @type string $token_type
* @type string $id_token
* }
*/
public function fetchAuthToken(?callable $httpHandler = null)
{
$httpHandler = $httpHandler ?? HttpHandlerFactory::build(HttpClientCache::getHttpClient());
// The FetchAuthTokenInterface technically does not have a "headers" argument, but all of
// the implementations do. Additionally, passing in more parameters than the function has
// defined is allowed in PHP. So we'll just ignore the phpstan error here.
// @phpstan-ignore-next-line
$authToken = $this->sourceCredentials->fetchAuthToken(
$httpHandler,
$this->applyTokenEndpointMetrics([], 'at')
);
$headers = $this->applyTokenEndpointMetrics([
'Content-Type' => 'application/json',
'Cache-Control' => 'no-store',
'Authorization' => sprintf('Bearer %s', $authToken['access_token'] ?? $authToken['id_token']),
], 'at');
$body = [
'scope' => $this->targetScope,
'delegates' => $this->delegates,
'lifetime' => sprintf('%ss', $this->lifetime),
];
$request = new Request(
'POST',
$this->serviceAccountImpersonationUrl,
$headers,
(string) json_encode($body)
);
$response = $httpHandler($request);
$body = json_decode((string) $response->getBody(), true);
return [
'access_token' => $body['accessToken'],
'expires_at' => strtotime($body['expireTime']),
];
}
/**
* Returns the Cache Key for the credentials
* The cache key is the same as the UserRefreshCredentials class
*
* @return string
*/
public function getCacheKey()
{
return $this->getFullCacheKey(
$this->serviceAccountImpersonationUrl . $this->sourceCredentials->getCacheKey()
);
}
/**
* @return array<mixed>
*/
public function getLastReceivedToken()
{
return $this->sourceCredentials->getLastReceivedToken();
}
protected function getCredType(): string
{
return self::CRED_TYPE;
}
}
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