<?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;
use Google\Auth\Credentials\InsecureCredentials;
use Google\Auth\Credentials\ServiceAccountCredentials;
use Google\Auth\Credentials\UserRefreshCredentials;
/**
* CredentialsLoader contains the behaviour used to locate and find default
* credentials files on the file system.
*/
abstract class CredentialsLoader implements FetchAuthTokenInterface
{
const TOKEN_CREDENTIAL_URI = 'https://oauth2.googleapis.com/token';
const ENV_VAR = 'GOOGLE_APPLICATION_CREDENTIALS';
const WELL_KNOWN_PATH = 'gcloud/application_default_credentials.json';
const NON_WINDOWS_WELL_KNOWN_PATH_BASE = '.config';
const AUTH_METADATA_KEY = 'authorization';
/**
* @param string $cause
* @return string
*/
private static function unableToReadEnv($cause)
{
$msg = 'Unable to read the credential file specified by ';
$msg .= ' GOOGLE_APPLICATION_CREDENTIALS: ';
$msg .= $cause;
return $msg;
}
/**
* @return bool
*/
private static function isOnWindows()
{
return strtoupper(substr(PHP_OS, 0, 3)) === 'WIN';
}
/**
* Load a JSON key from the path specified in the environment.
*
* Load a JSON key from the path specified in the environment
* variable GOOGLE_APPLICATION_CREDENTIALS. Return null if
* GOOGLE_APPLICATION_CREDENTIALS is not specified.
*
* @return array JSON key | null
*/
public static function fromEnv()
{
$path = getenv(self::ENV_VAR);
if (empty($path)) {
return;
}
if (!file_exists($path)) {
$cause = 'file ' . $path . ' does not exist';
throw new \DomainException(self::unableToReadEnv($cause));
}
$jsonKey = file_get_contents($path);
return json_decode($jsonKey, true);
}
/**
* Load a JSON key from a well known path.
*
* The well known path is OS dependent:
* - windows: %APPDATA%/gcloud/application_default_credentials.json
* - others: $HOME/.config/gcloud/application_default_credentials.json
*
* If the file does not exists, this returns null.
*
* @return array JSON key | null
*/
public static function fromWellKnownFile()
{
$rootEnv = self::isOnWindows() ? 'APPDATA' : 'HOME';
$path = [getenv($rootEnv)];
if (!self::isOnWindows()) {
$path[] = self::NON_WINDOWS_WELL_KNOWN_PATH_BASE;
}
$path[] = self::WELL_KNOWN_PATH;
$path = implode(DIRECTORY_SEPARATOR, $path);
if (!file_exists($path)) {
return;
}
$jsonKey = file_get_contents($path);
return json_decode($jsonKey, true);
}
/**
* Create a new Credentials instance.
*
* @param string|array $scope the scope of the access request, expressed
* either as an Array or as a space-delimited String.
* @param array $jsonKey the JSON credentials.
*
* @return ServiceAccountCredentials|UserRefreshCredentials
*/
public static function makeCredentials($scope, array $jsonKey)
{
if (!array_key_exists('type', $jsonKey)) {
throw new \InvalidArgumentException('json key is missing the type field');
}
if ($jsonKey['type'] == 'service_account') {
return new ServiceAccountCredentials($scope, $jsonKey);
}
if ($jsonKey['type'] == 'authorized_user') {
return new UserRefreshCredentials($scope, $jsonKey);
}
throw new \InvalidArgumentException('invalid value in the type field');
}
/**
* Create an authorized HTTP Client from an instance of FetchAuthTokenInterface.
*
* @param FetchAuthTokenInterface $fetcher is used to fetch the auth token
* @param array $httpClientOptoins (optional) Array of request options to apply.
* @param callable $httpHandler (optional) http client to fetch the token.
* @param callable $tokenCallback (optional) function to be called when a new token is fetched.
*
* @return \GuzzleHttp\Client
*/
public static function makeHttpClient(
FetchAuthTokenInterface $fetcher,
array $httpClientOptions = [],
callable $httpHandler = null,
callable $tokenCallback = null
) {
$version = \GuzzleHttp\ClientInterface::VERSION;
switch ($version[0]) {
case '5':
$client = new \GuzzleHttp\Client($httpClientOptions);
$client->setDefaultOption('auth', 'google_auth');
$subscriber = new Subscriber\AuthTokenSubscriber(
$fetcher,
$httpHandler,
$tokenCallback
);
$client->getEmitter()->attach($subscriber);
return $client;
case '6':
$middleware = new Middleware\AuthTokenMiddleware(
$fetcher,
$httpHandler,
$tokenCallback
);
$stack = \GuzzleHttp\HandlerStack::create();
$stack->push($middleware);
return new \GuzzleHttp\Client([
'handler' => $stack,
'auth' => 'google_auth',
] + $httpClientOptions);
default:
throw new \Exception('Version not supported');
}
}
/**
* Create a new instance of InsecureCredentials.
*
* @return InsecureCredentials
*/
public static function makeInsecureCredentials()
{
return new InsecureCredentials();
}
/**
* export a callback function which updates runtime metadata.
*
* @return array updateMetadata function
*/
public function getUpdateMetadataFunc()
{
return array($this, 'updateMetadata');
}
/**
* 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
) {
$result = $this->fetchAuthToken($httpHandler);
if (!isset($result['access_token'])) {
return $metadata;
}
$metadata_copy = $metadata;
$metadata_copy[self::AUTH_METADATA_KEY] = array('Bearer ' . $result['access_token']);
return $metadata_copy;
}
}