Initial commit

vendor/google/auth/src/ApplicationDefaultCredentials.php

@@ -0,0 +1,173 @@
+<?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 DomainException;
+use Google\Auth\Credentials\AppIdentityCredentials;
+use Google\Auth\Credentials\GCECredentials;
+use Google\Auth\Middleware\AuthTokenMiddleware;
+use Google\Auth\Subscriber\AuthTokenSubscriber;
+use Psr\Cache\CacheItemPoolInterface;
+
+/**
+ * ApplicationDefaultCredentials obtains the default credentials for
+ * authorizing a request to a Google service.
+ *
+ * Application Default Credentials are described here:
+ * https://developers.google.com/accounts/docs/application-default-credentials
+ *
+ * This class implements the search for the application default credentials as
+ * described in the link.
+ *
+ * It provides three factory methods:
+ * - #get returns the computed credentials object
+ * - #getSubscriber returns an AuthTokenSubscriber built from the credentials object
+ * - #getMiddleware returns an AuthTokenMiddleware built from the credentials object
+ *
+ * This allows it to be used as follows with GuzzleHttp\Client:
+ *
+ *   use Google\Auth\ApplicationDefaultCredentials;
+ *   use GuzzleHttp\Client;
+ *   use GuzzleHttp\HandlerStack;
+ *
+ *   $middleware = ApplicationDefaultCredentials::getMiddleware(
+ *       'https://www.googleapis.com/auth/taskqueue'
+ *   );
+ *   $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 ApplicationDefaultCredentials
+{
+    /**
+     * Obtains an AuthTokenSubscriber that uses the default FetchAuthTokenInterface
+     * implementation to use in this environment.
+     *
+     * If supplied, $scope is used to in creating the credentials instance if
+     * this does not fallback to the compute engine defaults.
+     *
+     * @param string|array scope the scope of the access request, expressed
+     *   either as an Array or as a space-delimited String.
+     * @param callable $httpHandler callback which delivers psr7 request
+     * @param array $cacheConfig configuration for the cache when it's present
+     * @param CacheItemPoolInterface $cache an implementation of CacheItemPoolInterface
+     *
+     * @return AuthTokenSubscriber
+     *
+     * @throws DomainException if no implementation can be obtained.
+     */
+    public static function getSubscriber(
+        $scope = null,
+        callable $httpHandler = null,
+        array $cacheConfig = null,
+        CacheItemPoolInterface $cache = null
+    ) {
+        $creds = self::getCredentials($scope, $httpHandler, $cacheConfig, $cache);
+
+        return new AuthTokenSubscriber($creds, $cacheConfig);
+    }
+
+    /**
+     * Obtains an AuthTokenMiddleware that uses the default FetchAuthTokenInterface
+     * implementation to use in this environment.
+     *
+     * If supplied, $scope is used to in creating the credentials instance if
+     * this does not fallback to the compute engine defaults.
+     *
+     * @param string|array scope the scope of the access request, expressed
+     *   either as an Array or as a space-delimited String.
+     * @param callable $httpHandler callback which delivers psr7 request
+     * @param array $cacheConfig configuration for the cache when it's present
+     * @param CacheItemPoolInterface $cache
+     *
+     * @return AuthTokenMiddleware
+     *
+     * @throws DomainException if no implementation can be obtained.
+     */
+    public static function getMiddleware(
+        $scope = null,
+        callable $httpHandler = null,
+        array $cacheConfig = null,
+        CacheItemPoolInterface $cache = null
+    ) {
+        $creds = self::getCredentials($scope, $httpHandler, $cacheConfig, $cache);
+
+        return new AuthTokenMiddleware($creds, $cacheConfig);
+    }
+
+    /**
+     * Obtains the default FetchAuthTokenInterface implementation to use
+     * in this environment.
+     *
+     * If supplied, $scope is used to in creating the credentials instance if
+     * this does not fallback to the Compute Engine defaults.
+     *
+     * @param string|array scope the scope of the access request, expressed
+     *   either as an Array or as a space-delimited String.
+     * @param callable $httpHandler callback which delivers psr7 request
+     * @param array $cacheConfig configuration for the cache when it's present
+     * @param CacheItemPoolInterface $cache
+     *
+     * @return CredentialsLoader
+     *
+     * @throws DomainException if no implementation can be obtained.
+     */
+    public static function getCredentials(
+        $scope = null,
+        callable $httpHandler = null,
+        array $cacheConfig = null,
+        CacheItemPoolInterface $cache = null
+    ) {
+        $creds = null;
+        $jsonKey = CredentialsLoader::fromEnv()
+            ?: CredentialsLoader::fromWellKnownFile();
+
+        if (!is_null($jsonKey)) {
+            $creds = CredentialsLoader::makeCredentials($scope, $jsonKey);
+        } elseif (AppIdentityCredentials::onAppEngine() && !GCECredentials::onAppEngineFlexible()) {
+            $creds = new AppIdentityCredentials($scope);
+        } elseif (GCECredentials::onGce($httpHandler)) {
+            $creds = new GCECredentials();
+        }
+
+        if (is_null($creds)) {
+            throw new \DomainException(self::notFound());
+        }
+        if (!is_null($cache)) {
+            $creds = new FetchAuthTokenCache($creds, $cacheConfig, $cache);
+        }
+        return $creds;
+    }
+
+    private static function notFound()
+    {
+        $msg = 'Could not load the default credentials. Browse to ';
+        $msg .= 'https://developers.google.com';
+        $msg .= '/accounts/docs/application-default-credentials';
+        $msg .= ' for more information';
+
+        return $msg;
+    }
+}

vendor/google/auth/src/Cache/InvalidArgumentException.php

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+<?php
+/*
+ * Copyright 2016 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\Cache;
+
+use Psr\Cache\InvalidArgumentException as PsrInvalidArgumentException;
+
+class InvalidArgumentException extends \InvalidArgumentException implements PsrInvalidArgumentException
+{
+}

vendor/google/auth/src/Cache/Item.php

@@ -0,0 +1,185 @@
+<?php
+/*
+ * Copyright 2016 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\Cache;
+
+use Psr\Cache\CacheItemInterface;
+
+/**
+ * A cache item.
+ */
+final class Item implements CacheItemInterface
+{
+    /**
+     * @var string
+     */
+    private $key;
+
+    /**
+     * @var mixed
+     */
+    private $value;
+
+    /**
+     * @var \DateTime
+     */
+    private $expiration;
+
+    /**
+     * @var bool
+     */
+    private $isHit = false;
+
+    /**
+     * @param string $key
+     */
+    public function __construct($key)
+    {
+        $this->key = $key;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getKey()
+    {
+        return $this->key;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function get()
+    {
+        return $this->isHit() ? $this->value : null;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isHit()
+    {
+        if (!$this->isHit) {
+            return false;
+        }
+
+        if ($this->expiration === null) {
+            return true;
+        }
+
+        return new \DateTime() < $this->expiration;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function set($value)
+    {
+        $this->isHit = true;
+        $this->value = $value;
+
+        return $this;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function expiresAt($expiration)
+    {
+        if ($this->isValidExpiration($expiration)) {
+            $this->expiration = $expiration;
+
+            return $this;
+        }
+
+        $implementationMessage = interface_exists('DateTimeInterface')
+            ? 'implement interface DateTimeInterface'
+            : 'be an instance of DateTime';
+
+        $error = sprintf(
+            'Argument 1 passed to %s::expiresAt() must %s, %s given',
+            get_class($this),
+            $implementationMessage,
+            gettype($expiration)
+        );
+
+        $this->handleError($error);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function expiresAfter($time)
+    {
+        if (is_int($time)) {
+            $this->expiration = new \DateTime("now + $time seconds");
+        } elseif ($time instanceof \DateInterval) {
+            $this->expiration = (new \DateTime())->add($time);
+        } elseif ($time === null) {
+            $this->expiration = $time;
+        } else {
+            $message = 'Argument 1 passed to %s::expiresAfter() must be an ' .
+                       'instance of DateInterval or of the type integer, %s given';
+            $error = sprintf($message, get_class($this), gettype($expiration));
+
+            $this->handleError($error);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Handles an error.
+     *
+     * @param string $error
+     * @throws \TypeError
+     */
+    private function handleError($error)
+    {
+        if (class_exists('TypeError')) {
+            throw new \TypeError($error);
+        }
+
+        trigger_error($error, E_USER_ERROR);
+    }
+
+    /**
+     * Determines if an expiration is valid based on the rules defined by PSR6.
+     *
+     * @param mixed $expiration
+     * @return bool
+     */
+    private function isValidExpiration($expiration)
+    {
+        if ($expiration === null) {
+            return true;
+        }
+
+        // We test for two types here due to the fact the DateTimeInterface
+        // was not introduced until PHP 5.5. Checking for the DateTime type as
+        // well allows us to support 5.4.
+        if ($expiration instanceof \DateTimeInterface) {
+            return true;
+        }
+
+        if ($expiration instanceof \DateTime) {
+            return true;
+        }
+
+        return false;
+    }
+}

vendor/google/auth/src/Cache/MemoryCacheItemPool.php

@@ -0,0 +1,155 @@
+<?php
+/*
+ * Copyright 2016 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\Cache;
+
+use Psr\Cache\CacheItemInterface;
+use Psr\Cache\CacheItemPoolInterface;
+
+/**
+ * Simple in-memory cache implementation.
+ */
+final class MemoryCacheItemPool implements CacheItemPoolInterface
+{
+    /**
+     * @var CacheItemInterface[]
+     */
+    private $items;
+
+    /**
+     * @var CacheItemInterface[]
+     */
+    private $deferredItems;
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getItem($key)
+    {
+        return current($this->getItems([$key]));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getItems(array $keys = [])
+    {
+        $items = [];
+
+        foreach ($keys as $key) {
+            $this->isValidKey($key);
+            $items[$key] = $this->hasItem($key) ? clone $this->items[$key] : new Item($key);
+        }
+
+        return $items;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function hasItem($key)
+    {
+        $this->isValidKey($key);
+
+        return isset($this->items[$key]) && $this->items[$key]->isHit();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function clear()
+    {
+        $this->items = [];
+        $this->deferred = [];
+
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function deleteItem($key)
+    {
+        return $this->deleteItems([$key]);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function deleteItems(array $keys)
+    {
+        array_walk($keys, [$this, 'isValidKey']);
+
+        foreach ($keys as $key) {
+            unset($this->items[$key]);
+        }
+
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function save(CacheItemInterface $item)
+    {
+        $this->items[$item->getKey()] = $item;
+
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function saveDeferred(CacheItemInterface $item)
+    {
+        $this->deferredItems[$item->getKey()] = $item;
+
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function commit()
+    {
+        foreach ($this->deferredItems as $item) {
+            $this->save($item);
+        }
+
+        $this->deferredItems = [];
+
+        return true;
+    }
+
+    /**
+     * Determines if the provided key is valid.
+     *
+     * @param string $key
+     * @return bool
+     * @throws InvalidArgumentException
+     */
+    private function isValidKey($key)
+    {
+        $invalidCharacters = '{}()/\\\\@:';
+
+        if (!is_string($key) || preg_match("#[$invalidCharacters]#", $key)) {
+            throw new InvalidArgumentException('The provided key is not valid: ' . var_export($key, true));
+        }
+
+        return true;
+    }
+}

vendor/google/auth/src/CacheTrait.php

@@ -0,0 +1,72 @@
+<?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;
+
+trait CacheTrait
+{
+    /**
+     * Gets the cached value if it is present in the cache when that is
+     * available.
+     */
+    private function getCachedValue($k)
+    {
+        if (is_null($this->cache)) {
+            return;
+        }
+
+        $key = $this->getFullCacheKey($k);
+        if (is_null($key)) {
+            return;
+        }
+
+        $cacheItem = $this->cache->getItem($key);
+        return $cacheItem->get();
+    }
+
+    /**
+     * Saves the value in the cache when that is available.
+     */
+    private function setCachedValue($k, $v)
+    {
+        if (is_null($this->cache)) {
+            return;
+        }
+
+        $key = $this->getFullCacheKey($k);
+        if (is_null($key)) {
+            return;
+        }
+
+        $cacheItem = $this->cache->getItem($key);
+        $cacheItem->set($v);
+        $cacheItem->expiresAfter($this->cacheConfig['lifetime']);
+        return $this->cache->save($cacheItem);
+    }
+
+    private function getFullCacheKey($key)
+    {
+        if (is_null($key)) {
+            return;
+        }
+
+        $key = $this->cacheConfig['prefix'] . $key;
+
+        // ensure we do not have illegal characters
+        return preg_replace('|[^a-zA-Z0-9_\.!]|', '', $key);
+    }
+}

vendor/google/auth/src/Credentials/AppIdentityCredentials.php

@@ -0,0 +1,149 @@
+<?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;
+
+/*
+ * The AppIdentityService class is automatically defined on App Engine,
+ * so including this dependency is not necessary, and will result in a
+ * PHP fatal error in the App Engine environment.
+ */
+use google\appengine\api\app_identity\AppIdentityService;
+use Google\Auth\CredentialsLoader;
+
+/**
+ * AppIdentityCredentials supports authorization on Google App Engine.
+ *
+ * It can be used to authorize requests using the AuthTokenMiddleware or
+ * AuthTokenSubscriber, but will only succeed if being run on App Engine:
+ *
+ *   use Google\Auth\Credentials\AppIdentityCredentials;
+ *   use Google\Auth\Middleware\AuthTokenMiddleware;
+ *   use GuzzleHttp\Client;
+ *   use GuzzleHttp\HandlerStack;
+ *
+ *   $gae = new AppIdentityCredentials('https://www.googleapis.com/auth/books');
+ *   $middleware = new AuthTokenMiddleware($gae);
+ *   $stack = HandlerStack::create();
+ *   $stack->push($middleware);
+ *
+ *   $client = new Client([
+ *       'handler' => $stack,
+ *       'base_uri' => 'https://www.googleapis.com/books/v1',
+ *       'auth' => 'google_auth'
+ *   ]);
+ *
+ *   $res = $client->get('volumes?q=Henry+David+Thoreau&country=US');
+ */
+class AppIdentityCredentials extends CredentialsLoader
+{
+    /**
+     * Result of fetchAuthToken.
+     *
+     * @array
+     */
+    protected $lastReceivedToken;
+
+    /**
+     * Array of OAuth2 scopes to be requested.
+     */
+    private $scope;
+
+    public function __construct($scope = array())
+    {
+        $this->scope = $scope;
+    }
+
+    /**
+     * Determines if this an App Engine instance, by accessing the SERVER_SOFTWARE
+     * environment variable.
+     *
+     * @return true if this an App Engine Instance, false otherwise
+     */
+    public static function onAppEngine()
+    {
+        return isset($_SERVER['SERVER_SOFTWARE']) &&
+        strpos($_SERVER['SERVER_SOFTWARE'], 'Google App Engine') !== false;
+    }
+
+    /**
+     * Implements FetchAuthTokenInterface#fetchAuthToken.
+     *
+     * Fetches the auth tokens using the AppIdentityService if available.
+     * As the AppIdentityService uses protobufs to fetch the access token,
+     * the GuzzleHttp\ClientInterface instance passed in will not be used.
+     *
+     * @param callable $httpHandler callback which delivers psr7 request
+     *
+     * @return array the auth metadata:
+     *  array(2) {
+     *   ["access_token"]=>
+     *   string(3) "xyz"
+     *   ["expiration_time"]=>
+     *   string(10) "1444339905"
+     *  }
+     *
+     * @throws \Exception
+     */
+    public function fetchAuthToken(callable $httpHandler = null)
+    {
+        if (!self::onAppEngine()) {
+            return array();
+        }
+
+        if (!class_exists('google\appengine\api\app_identity\AppIdentityService')) {
+            throw new \Exception(
+                'This class must be run in App Engine, or you must include the AppIdentityService '
+                . 'mock class defined in tests/mocks/AppIdentityService.php'
+            );
+        }
+
+        // AppIdentityService expects an array when multiple scopes are supplied
+        $scope = is_array($this->scope) ? $this->scope : explode(' ', $this->scope);
+
+        $token = AppIdentityService::getAccessToken($scope);
+        $this->lastReceivedToken = $token;
+
+        return $token;
+    }
+
+    /**
+     * @return array|null
+     */
+    public function getLastReceivedToken()
+    {
+        if ($this->lastReceivedToken) {
+            return [
+                'access_token' => $this->lastReceivedToken['access_token'],
+                'expires_at' => $this->lastReceivedToken['expiration_time'],
+            ];
+        }
+
+        return null;
+    }
+
+    /**
+     * Caching is handled by the underlying AppIdentityService, return empty string
+     * to prevent caching.
+     *
+     * @return string
+     */
+    public function getCacheKey()
+    {
+        return '';
+    }
+}

vendor/google/auth/src/Credentials/GCECredentials.php

@@ -0,0 +1,219 @@
+<?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\HttpHandler\HttpHandlerFactory;
+use GuzzleHttp\Exception\ClientException;
+use GuzzleHttp\Exception\RequestException;
+use GuzzleHttp\Exception\ServerException;
+use GuzzleHttp\Psr7\Request;
+
+/**
+ * GCECredentials supports authorization on Google Compute Engine.
+ *
+ * It can be used to authorize requests using the AuthTokenMiddleware, but will
+ * only succeed if being run on GCE:
+ *
+ *   use Google\Auth\Credentials\GCECredentials;
+ *   use Google\Auth\Middleware\AuthTokenMiddleware;
+ *   use GuzzleHttp\Client;
+ *   use GuzzleHttp\HandlerStack;
+ *
+ *   $gce = new GCECredentials();
+ *   $middleware = new AuthTokenMiddleware($gce);
+ *   $stack = HandlerStack::create();
+ *   $stack->push($middleware);
+ *
+ *   $client = new Client([
+ *      'handler' => $stack,
+ *      'base_uri' => 'https://www.googleapis.com/taskqueue/v1beta2/projects/',
+ *      'auth' => 'google_auth'
+ *   ]);
+ *
+ *   $res = $client->get('myproject/taskqueues/myqueue');
+ */
+class GCECredentials extends CredentialsLoader
+{
+    const cacheKey = 'GOOGLE_AUTH_PHP_GCE';
+    /**
+     * The metadata IP address on appengine instances.
+     *
+     * The IP is used instead of the domain 'metadata' to avoid slow responses
+     * when not on Compute Engine.
+     */
+    const METADATA_IP = '169.254.169.254';
+
+    /**
+     * The metadata path of the default token.
+     */
+    const TOKEN_URI_PATH = 'v1/instance/service-accounts/default/token';
+
+    /**
+     * The header whose presence indicates GCE presence.
+     */
+    const FLAVOR_HEADER = 'Metadata-Flavor';
+
+    /**
+     * Flag used to ensure that the onGCE test is only done once;.
+     *
+     * @var bool
+     */
+    private $hasCheckedOnGce = false;
+
+    /**
+     * Flag that stores the value of the onGCE check.
+     *
+     * @var bool
+     */
+    private $isOnGce = false;
+
+    /**
+     * Result of fetchAuthToken.
+     */
+    protected $lastReceivedToken;
+
+    /**
+     * The full uri for accessing the default token.
+     *
+     * @return string
+     */
+    public static function getTokenUri()
+    {
+        $base = 'http://' . self::METADATA_IP . '/computeMetadata/';
+
+        return $base . self::TOKEN_URI_PATH;
+    }
+
+    /**
+     * Determines if this an App Engine Flexible instance, by accessing the
+     * GAE_VM environment variable.
+     *
+     * @return true if this an App Engine Flexible Instance, false otherwise
+     */
+    public static function onAppEngineFlexible()
+    {
+        return isset($_SERVER['GAE_VM']) && 'true' === $_SERVER['GAE_VM'];
+    }
+
+    /**
+     * Determines if this a GCE instance, by accessing the expected metadata
+     * host.
+     * If $httpHandler is not specified a the default HttpHandler is used.
+     *
+     * @param callable $httpHandler callback which delivers psr7 request
+     *
+     * @return true if this a GCEInstance false otherwise
+     */
+    public static function onGce(callable $httpHandler = null)
+    {
+        if (is_null($httpHandler)) {
+            $httpHandler = HttpHandlerFactory::build();
+        }
+        $checkUri = 'http://' . self::METADATA_IP;
+        try {
+            // Comment from: oauth2client/client.py
+            //
+            // Note: the explicit `timeout` below is a workaround. The underlying
+            // issue is that resolving an unknown host on some networks will take
+            // 20-30 seconds; making this timeout short fixes the issue, but
+            // could lead to false negatives in the event that we are on GCE, but
+            // the metadata resolution was particularly slow. The latter case is
+            // "unlikely".
+            $resp = $httpHandler(
+                new Request('GET', $checkUri),
+                ['timeout' => 0.3]
+            );
+
+            return $resp->getHeaderLine(self::FLAVOR_HEADER) == 'Google';
+        } catch (ClientException $e) {
+            return false;
+        } catch (ServerException $e) {
+            return false;
+        } catch (RequestException $e) {
+            return false;
+        }
+    }
+
+    /**
+     * Implements FetchAuthTokenInterface#fetchAuthToken.
+     *
+     * Fetches the auth tokens from the GCE metadata host if it is available.
+     * If $httpHandler is not specified a the default HttpHandler is used.
+     *
+     * @param callable $httpHandler callback which delivers psr7 request
+     *
+     * @return array the response
+     *
+     * @throws \Exception
+     */
+    public function fetchAuthToken(callable $httpHandler = null)
+    {
+        if (is_null($httpHandler)) {
+            $httpHandler = HttpHandlerFactory::build();
+        }
+        if (!$this->hasCheckedOnGce) {
+            $this->isOnGce = self::onGce($httpHandler);
+        }
+        if (!$this->isOnGce) {
+            return array();  // return an empty array with no access token
+        }
+        $resp = $httpHandler(
+            new Request(
+                'GET',
+                self::getTokenUri(),
+                [self::FLAVOR_HEADER => 'Google']
+            )
+        );
+        $body = (string)$resp->getBody();
+
+        // Assume it's JSON; if it's not throw an exception
+        if (null === $json = json_decode($body, true)) {
+            throw new \Exception('Invalid JSON response');
+        }
+
+        // store this so we can retrieve it later
+        $this->lastReceivedToken = $json;
+        $this->lastReceivedToken['expires_at'] = time() + $json['expires_in'];
+
+        return $json;
+    }
+
+    /**
+     * @return string
+     */
+    public function getCacheKey()
+    {
+        return self::cacheKey;
+    }
+
+    /**
+     * @return array|null
+     */
+    public function getLastReceivedToken()
+    {
+        if ($this->lastReceivedToken) {
+            return [
+                'access_token' => $this->lastReceivedToken['access_token'],
+                'expires_at' => $this->lastReceivedToken['expires_at'],
+            ];
+        }
+
+        return null;
+    }
+}

vendor/google/auth/src/Credentials/IAMCredentials.php

@@ -0,0 +1,89 @@
+<?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;
+
+/**
+ * Authenticates requests using IAM credentials.
+ */
+class IAMCredentials
+{
+    const SELECTOR_KEY = 'x-goog-iam-authority-selector';
+    const TOKEN_KEY = 'x-goog-iam-authorization-token';
+
+    /**
+     * @var string
+     */
+    private $selector;
+
+    /**
+     * @var string
+     */
+    private $token;
+
+    /**
+     * @param $selector string the IAM selector
+     * @param $token string the IAM token
+     */
+    public function __construct($selector, $token)
+    {
+        if (!is_string($selector)) {
+            throw new \InvalidArgumentException(
+                'selector must be a string');
+        }
+        if (!is_string($token)) {
+            throw new \InvalidArgumentException(
+                'token must be a string');
+        }
+
+        $this->selector = $selector;
+        $this->token = $token;
+    }
+
+    /**
+     * export a callback function which updates runtime metadata.
+     *
+     * @return array updateMetadata function
+     */
+    public function getUpdateMetadataFunc()
+    {
+        return array($this, 'updateMetadata');
+    }
+
+    /**
+     * Updates metadata with the appropriate header metadata.
+     *
+     * @param array $metadata metadata hashmap
+     * @param string $unusedAuthUri optional auth uri
+     * @param callable $httpHandler callback which delivers psr7 request
+     *        Note: this param is unused here, only included here for
+     *        consistency with other credentials class
+     *
+     * @return array updated metadata hashmap
+     */
+    public function updateMetadata(
+        $metadata,
+        $unusedAuthUri = null,
+        callable $httpHandler = null
+    ) {
+        $metadata_copy = $metadata;
+        $metadata_copy[self::SELECTOR_KEY] = $this->selector;
+        $metadata_copy[self::TOKEN_KEY] = $this->token;
+
+        return $metadata_copy;
+    }
+}

vendor/google/auth/src/Credentials/ServiceAccountCredentials.php

@@ -0,0 +1,177 @@
+<?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\OAuth2;
+
+/**
+ * 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
+{
+    /**
+     * The OAuth2 instance used to conduct authorization.
+     *
+     * @var OAuth2
+     */
+    protected $auth;
+
+    /**
+     * 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.
+     */
+    public function __construct(
+        $scope,
+        $jsonKey,
+        $sub = null
+    ) {
+        if (is_string($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');
+        }
+        $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,
+        ]);
+    }
+
+    /**
+     * @param callable $httpHandler
+     *
+     * @return array
+     */
+    public function fetchAuthToken(callable $httpHandler = null)
+    {
+        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()
+    {
+        return $this->auth->getLastReceivedToken();
+    }
+
+    /**
+     * 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
+        $scope = $this->auth->getScope();
+        if (!is_null($scope)) {
+            return parent::updateMetadata($metadata, $authUri, $httpHandler);
+        }
+
+        // no scope found. create jwt with the auth uri
+        $credJson = array(
+            'private_key' => $this->auth->getSigningKey(),
+            'client_email' => $this->auth->getIssuer(),
+        );
+        $jwtCreds = new ServiceAccountJwtAccessCredentials($credJson);
+
+        return $jwtCreds->updateMetadata($metadata, $authUri, $httpHandler);
+    }
+
+    /**
+     * @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);
+    }
+}

vendor/google/auth/src/Credentials/ServiceAccountJwtAccessCredentials.php

@@ -0,0 +1,131 @@
+<?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\OAuth2;
+
+/**
+ * Authenticates requests using Google's Service Account credentials via
+ * JWT Access.
+ *
+ * This class allows authorizing requests for service accounts directly
+ * from credentials from a json key file downloaded from the developer
+ * console (via 'Generate new Json Key').  It is not part of any OAuth2
+ * flow, rather it creates a JWT and sends that as a credential.
+ */
+class ServiceAccountJwtAccessCredentials extends CredentialsLoader
+{
+    /**
+     * The OAuth2 instance used to conduct authorization.
+     *
+     * @var OAuth2
+     */
+    protected $auth;
+
+    /**
+     * Create a new ServiceAccountJwtAccessCredentials.
+     *
+     * @param string|array $jsonKey JSON credential file path or JSON credentials
+     *   as an associative array
+     */
+    public function __construct($jsonKey)
+    {
+        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');
+        }
+        $this->auth = new OAuth2([
+            'issuer' => $jsonKey['client_email'],
+            'sub' => $jsonKey['client_email'],
+            'signingAlgorithm' => 'RS256',
+            'signingKey' => $jsonKey['private_key'],
+        ]);
+    }
+
+    /**
+     * 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 $httpHandler = null
+    ) {
+        if (empty($authUri)) {
+            return $metadata;
+        }
+
+        $this->auth->setAudience($authUri);
+
+        return parent::updateMetadata($metadata, $authUri, $httpHandler);
+    }
+
+    /**
+     * Implements FetchAuthTokenInterface#fetchAuthToken.
+     *
+     * @param callable $httpHandler
+     *
+     * @return array|void
+     */
+    public function fetchAuthToken(callable $httpHandler = null)
+    {
+        $audience = $this->auth->getAudience();
+        if (empty($audience)) {
+            return null;
+        }
+
+        $access_token = $this->auth->toJwt();
+
+        return array('access_token' => $access_token);
+    }
+
+    /**
+     * @return string
+     */
+    public function getCacheKey()
+    {
+        return $this->auth->getCacheKey();
+    }
+
+    /**
+     * @return array
+     */
+    public function getLastReceivedToken()
+    {
+        return $this->auth->getLastReceivedToken();
+    }
+}

vendor/google/auth/src/Credentials/UserRefreshCredentials.php

@@ -0,0 +1,110 @@
+<?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\OAuth2;
+
+/**
+ * Authenticates requests using User Refresh credentials.
+ *
+ * This class allows authorizing requests from user refresh tokens.
+ *
+ * This the end of the result of a 3LO flow.  E.g, the end result of
+ * 'gcloud auth login' saves a file with these contents in well known
+ * location
+ *
+ * @see [Application Default Credentials](http://goo.gl/mkAHpZ)
+ */
+class UserRefreshCredentials extends CredentialsLoader
+{
+    /**
+     * The OAuth2 instance used to conduct authorization.
+     *
+     * @var OAuth2
+     */
+    protected $auth;
+
+    /**
+     * Create a new UserRefreshCredentials.
+     *
+     * @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
+     */
+    public function __construct(
+        $scope,
+        $jsonKey
+    ) {
+        if (is_string($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_id', $jsonKey)) {
+            throw new \InvalidArgumentException(
+                'json key is missing the client_id field');
+        }
+        if (!array_key_exists('client_secret', $jsonKey)) {
+            throw new \InvalidArgumentException(
+                'json key is missing the client_secret field');
+        }
+        if (!array_key_exists('refresh_token', $jsonKey)) {
+            throw new \InvalidArgumentException(
+                'json key is missing the refresh_token field');
+        }
+        $this->auth = new OAuth2([
+            'clientId' => $jsonKey['client_id'],
+            'clientSecret' => $jsonKey['client_secret'],
+            'refresh_token' => $jsonKey['refresh_token'],
+            'scope' => $scope,
+            'tokenCredentialUri' => self::TOKEN_CREDENTIAL_URI,
+        ]);
+    }
+
+    /**
+     * @param callable $httpHandler
+     *
+     * @return array
+     */
+    public function fetchAuthToken(callable $httpHandler = null)
+    {
+        return $this->auth->fetchAuthToken($httpHandler);
+    }
+
+    /**
+     * @return string
+     */
+    public function getCacheKey()
+    {
+        return $this->auth->getClientId() . ':' . $this->auth->getCacheKey();
+    }
+
+    /**
+     * @return array
+     */
+    public function getLastReceivedToken()
+    {
+        return $this->auth->getLastReceivedToken();
+    }
+}

vendor/google/auth/src/CredentialsLoader.php

@@ -0,0 +1,163 @@
+<?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\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://www.googleapis.com/oauth2/v4/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, $jsonKey);
+        } elseif ($jsonKey['type'] == 'authorized_user') {
+            return new UserRefreshCredentials($scope, $jsonKey);
+        } else {
+            throw new \InvalidArgumentException('invalid value in the type field');
+        }
+    }
+
+    /**
+     * export a callback function which updates runtime metadata.
+     *
+     * @return array updateMetadata function
+     */
+    public function getUpdateMetadataFunc()
+    {
+        return array($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;
+    }
+}

vendor/google/auth/src/FetchAuthTokenCache.php

@@ -0,0 +1,108 @@
+<?php
+/*
+ * Copyright 2010 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 Psr\Cache\CacheItemPoolInterface;
+
+/**
+ * A class to implement caching for any object implementing
+ * FetchAuthTokenInterface
+ */
+class FetchAuthTokenCache implements FetchAuthTokenInterface
+{
+    use CacheTrait;
+
+    /**
+     * @var FetchAuthTokenInterface
+     */
+    private $fetcher;
+
+    /**
+     * @var array
+     */
+    private $cacheConfig;
+
+    /**
+     * @var CacheItemPoolInterface
+     */
+    private $cache;
+
+    public function __construct(
+        FetchAuthTokenInterface $fetcher,
+        array $cacheConfig = null,
+        CacheItemPoolInterface $cache
+    ) {
+        $this->fetcher = $fetcher;
+        $this->cache = $cache;
+        $this->cacheConfig = array_merge([
+            'lifetime' => 1500,
+            'prefix' => '',
+        ], (array) $cacheConfig);
+    }
+
+    /**
+     * Implements FetchAuthTokenInterface#fetchAuthToken.
+     *
+     * Checks the cache for a valid auth token and fetches the auth tokens
+     * from the supplied fetcher.
+     *
+     * @param callable $httpHandler callback which delivers psr7 request
+     *
+     * @return array the response
+     *
+     * @throws \Exception
+     */
+    public function fetchAuthToken(callable $httpHandler = null)
+    {
+        // Use the cached value if its available.
+        //
+        // TODO: correct caching; update the call to setCachedValue to set the expiry
+        // to the value returned with the auth token.
+        //
+        // TODO: correct caching; enable the cache to be cleared.
+        $cacheKey = $this->fetcher->getCacheKey();
+        $cached = $this->getCachedValue($cacheKey);
+        if (!empty($cached)) {
+            return ['access_token' => $cached];
+        }
+
+        $auth_token = $this->fetcher->fetchAuthToken($httpHandler);
+
+        if (isset($auth_token['access_token'])) {
+            $this->setCachedValue($cacheKey, $auth_token['access_token']);
+        }
+
+        return $auth_token;
+    }
+
+    /**
+     * @return string
+     */
+    public function getCacheKey()
+    {
+        return $this->getFullCacheKey($this->fetcher->getCacheKey());
+    }
+
+    /**
+     * @return array|null
+     */
+    public function getLastReceivedToken()
+    {
+        return $this->fetcher->getLastReceivedToken();
+    }
+}

vendor/google/auth/src/FetchAuthTokenInterface.php

@@ -0,0 +1,55 @@
+<?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;
+
+/**
+ * An interface implemented by objects that can fetch auth tokens.
+ */
+interface FetchAuthTokenInterface
+{
+    /**
+     * Fetches the auth tokens based on the current state.
+     *
+     * @param callable $httpHandler callback which delivers psr7 request
+     *
+     * @return array a hash of auth tokens
+     */
+    public function fetchAuthToken(callable $httpHandler = null);
+
+    /**
+     * Obtains a key that can used to cache the results of #fetchAuthToken.
+     *
+     * If the value is empty, the auth token is not cached.
+     *
+     * @return string a key that may be used to cache the auth token.
+     */
+    public function getCacheKey();
+
+    /**
+     * Returns an associative array with the token and
+     * expiration time.
+     *
+     * @return null|array {
+     *      The last received access token.
+     *
+     * @var string $access_token The access token string.
+     * @var int $expires_at The time the token expires as a UNIX timestamp.
+     * }
+     */
+    public function getLastReceivedToken();
+}

vendor/google/auth/src/HttpHandler/Guzzle5HttpHandler.php

@@ -0,0 +1,68 @@
+<?php
+/**
+ * Copyright 2015 Google Inc. All Rights Reserved.
+ *
+ * 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\HttpHandler;
+
+use GuzzleHttp\ClientInterface;
+use GuzzleHttp\Psr7\Response;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+
+class Guzzle5HttpHandler
+{
+    /**
+     * @var ClientInterface
+     */
+    private $client;
+
+    /**
+     * @param ClientInterface $client
+     */
+    public function __construct(ClientInterface $client)
+    {
+        $this->client = $client;
+    }
+
+    /**
+     * Accepts a PSR-7 Request and an array of options and returns a PSR-7 response.
+     *
+     * @param RequestInterface $request
+     * @param array $options
+     *
+     * @return ResponseInterface
+     */
+    public function __invoke(RequestInterface $request, array $options = [])
+    {
+        $request = $this->client->createRequest(
+            $request->getMethod(),
+            $request->getUri(),
+            array_merge([
+                'headers' => $request->getHeaders(),
+                'body' => $request->getBody(),
+            ], $options)
+        );
+
+        $response = $this->client->send($request);
+
+        return new Response(
+            $response->getStatusCode(),
+            $response->getHeaders() ?: [],
+            $response->getBody(),
+            $response->getProtocolVersion(),
+            $response->getReasonPhrase()
+        );
+    }
+}

vendor/google/auth/src/HttpHandler/Guzzle6HttpHandler.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace Google\Auth\HttpHandler;
+
+use GuzzleHttp\ClientInterface;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+
+class Guzzle6HttpHandler
+{
+    /**
+     * @var ClientInterface
+     */
+    private $client;
+
+    /**
+     * @param ClientInterface $client
+     */
+    public function __construct(ClientInterface $client)
+    {
+        $this->client = $client;
+    }
+
+    /**
+     * Accepts a PSR-7 request and an array of options and returns a PSR-7 response.
+     *
+     * @param RequestInterface $request
+     * @param array $options
+     *
+     * @return ResponseInterface
+     */
+    public function __invoke(RequestInterface $request, array $options = [])
+    {
+        return $this->client->send($request, $options);
+    }
+}

vendor/google/auth/src/HttpHandler/HttpHandlerFactory.php

@@ -0,0 +1,47 @@
+<?php
+/**
+ * Copyright 2015 Google Inc. All Rights Reserved.
+ *
+ * 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\HttpHandler;
+
+use GuzzleHttp\Client;
+use GuzzleHttp\ClientInterface;
+
+class HttpHandlerFactory
+{
+    /**
+     * Builds out a default http handler for the installed version of guzzle.
+     *
+     * @param ClientInterface $client
+     *
+     * @return Guzzle5HttpHandler|Guzzle6HttpHandler
+     *
+     * @throws \Exception
+     */
+    public static function build(ClientInterface $client = null)
+    {
+        $version = ClientInterface::VERSION;
+        $client = $client ?: new Client();
+
+        switch ($version[0]) {
+            case '5':
+                return new Guzzle5HttpHandler($client);
+            case '6':
+                return new Guzzle6HttpHandler($client);
+            default:
+                throw new \Exception('Version not supported');
+        }
+    }
+}

vendor/google/auth/src/Middleware/AuthTokenMiddleware.php

@@ -0,0 +1,126 @@
+<?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\Middleware;
+
+use Google\Auth\FetchAuthTokenInterface;
+use Psr\Http\Message\RequestInterface;
+
+/**
+ * AuthTokenMiddleware is a Guzzle Middleware that adds an Authorization header
+ * provided by an object implementing FetchAuthTokenInterface.
+ *
+ * The FetchAuthTokenInterface#fetchAuthToken is used to obtain a hash; one of
+ * the values value in that hash is added as the authorization header.
+ *
+ * Requests will be accessed with the authorization header:
+ *
+ * 'Authorization' 'Bearer <value of auth_token>'
+ */
+class AuthTokenMiddleware
+{
+    /**
+     * @var callback
+     */
+    private $httpHandler;
+
+    /**
+     * @var FetchAuthTokenInterface
+     */
+    private $fetcher;
+
+    /**
+     * @var callable
+     */
+    private $tokenCallback;
+
+    /**
+     * Creates a new AuthTokenMiddleware.
+     *
+     * @param FetchAuthTokenInterface $fetcher is used to fetch the auth token
+     * @param callable $httpHandler (optional) callback which delivers psr7 request
+     * @param callable $tokenCallback (optional) function to be called when a new token is fetched.
+     */
+    public function __construct(
+        FetchAuthTokenInterface $fetcher,
+        callable $httpHandler = null,
+        callable $tokenCallback = null
+    ) {
+        $this->fetcher = $fetcher;
+        $this->httpHandler = $httpHandler;
+        $this->tokenCallback = $tokenCallback;
+    }
+
+    /**
+     * Updates the request with an Authorization header when auth is 'google_auth'.
+     *
+     *   use Google\Auth\Middleware\AuthTokenMiddleware;
+     *   use Google\Auth\OAuth2;
+     *   use GuzzleHttp\Client;
+     *   use GuzzleHttp\HandlerStack;
+     *
+     *   $config = [..<oauth config param>.];
+     *   $oauth2 = new OAuth2($config)
+     *   $middleware = new AuthTokenMiddleware($oauth2);
+     *   $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');
+     *
+     * @param callable $handler
+     *
+     * @return \Closure
+     */
+    public function __invoke(callable $handler)
+    {
+        return function (RequestInterface $request, array $options) use ($handler) {
+            // Requests using "auth"="google_auth" will be authorized.
+            if (!isset($options['auth']) || $options['auth'] !== 'google_auth') {
+                return $handler($request, $options);
+            }
+
+            $request = $request->withHeader('Authorization', 'Bearer ' . $this->fetchToken());
+
+            return $handler($request, $options);
+        };
+    }
+
+    /**
+     * Call fetcher to fetch the token.
+     *
+     * @return string
+     */
+    private function fetchToken()
+    {
+        $auth_tokens = $this->fetcher->fetchAuthToken($this->httpHandler);
+
+        if (array_key_exists('access_token', $auth_tokens)) {
+            // notify the callback if applicable
+            if ($this->tokenCallback) {
+                call_user_func($this->tokenCallback, $this->fetcher->getCacheKey(), $auth_tokens['access_token']);
+            }
+
+            return $auth_tokens['access_token'];
+        }
+    }
+}

vendor/google/auth/src/Middleware/ScopedAccessTokenMiddleware.php

@@ -0,0 +1,175 @@
+<?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\Middleware;
+
+use Google\Auth\CacheTrait;
+use Psr\Cache\CacheItemPoolInterface;
+use Psr\Http\Message\RequestInterface;
+
+/**
+ * ScopedAccessTokenMiddleware is a Guzzle Middleware that adds an Authorization
+ * header provided by a closure.
+ *
+ * The closure returns an access token, taking the scope, either a single
+ * string or an array of strings, as its value.  If provided, a cache will be
+ * used to preserve the access token for a given lifetime.
+ *
+ * Requests will be accessed with the authorization header:
+ *
+ * 'Authorization' 'Bearer <value of auth_token>'
+ */
+class ScopedAccessTokenMiddleware
+{
+    use CacheTrait;
+
+    const DEFAULT_CACHE_LIFETIME = 1500;
+
+    /**
+     * @var CacheItemPoolInterface
+     */
+    private $cache;
+
+    /**
+     * @var array configuration
+     */
+    private $cacheConfig;
+
+    /**
+     * @var callable
+     */
+    private $tokenFunc;
+
+    /**
+     * @var array|string
+     */
+    private $scopes;
+
+    /**
+     * Creates a new ScopedAccessTokenMiddleware.
+     *
+     * @param callable $tokenFunc a token generator function
+     * @param array|string $scopes the token authentication scopes
+     * @param array $cacheConfig configuration for the cache when it's present
+     * @param CacheItemPoolInterface $cache an implementation of CacheItemPoolInterface
+     */
+    public function __construct(
+        callable $tokenFunc,
+        $scopes,
+        array $cacheConfig = null,
+        CacheItemPoolInterface $cache = null
+    ) {
+        $this->tokenFunc = $tokenFunc;
+        if (!(is_string($scopes) || is_array($scopes))) {
+            throw new \InvalidArgumentException(
+                'wants scope should be string or array');
+        }
+        $this->scopes = $scopes;
+
+        if (!is_null($cache)) {
+            $this->cache = $cache;
+            $this->cacheConfig = array_merge([
+                'lifetime' => self::DEFAULT_CACHE_LIFETIME,
+                'prefix' => '',
+            ], $cacheConfig);
+        }
+    }
+
+    /**
+     * Updates the request with an Authorization header when auth is 'scoped'.
+     *
+     *   E.g this could be used to authenticate using the AppEngine
+     *   AppIdentityService.
+     *
+     *   use google\appengine\api\app_identity\AppIdentityService;
+     *   use Google\Auth\Middleware\ScopedAccessTokenMiddleware;
+     *   use GuzzleHttp\Client;
+     *   use GuzzleHttp\HandlerStack;
+     *
+     *   $scope = 'https://www.googleapis.com/auth/taskqueue'
+     *   $middleware = new ScopedAccessTokenMiddleware(
+     *       'AppIdentityService::getAccessToken',
+     *       $scope,
+     *       [ 'prefix' => 'Google\Auth\ScopedAccessToken::' ],
+     *       $cache = new Memcache()
+     *   );
+     *   $stack = HandlerStack::create();
+     *   $stack->push($middleware);
+     *
+     *   $client = new Client([
+     *       'handler' => $stack,
+     *       'base_url' => 'https://www.googleapis.com/taskqueue/v1beta2/projects/',
+     *       'auth' => 'google_auth' // authorize all requests
+     *   ]);
+     *
+     *   $res = $client->get('myproject/taskqueues/myqueue');
+     *
+     * @param callable $handler
+     *
+     * @return \Closure
+     */
+    public function __invoke(callable $handler)
+    {
+        return function (RequestInterface $request, array $options) use ($handler) {
+            // Requests using "auth"="scoped" will be authorized.
+            if (!isset($options['auth']) || $options['auth'] !== 'scoped') {
+                return $handler($request, $options);
+            }
+
+            $request = $request->withHeader('Authorization', 'Bearer ' . $this->fetchToken());
+
+            return $handler($request, $options);
+        };
+    }
+
+    /**
+     * @return string
+     */
+    private function getCacheKey()
+    {
+        $key = null;
+
+        if (is_string($this->scopes)) {
+            $key .= $this->scopes;
+        } elseif (is_array($this->scopes)) {
+            $key .= implode(':', $this->scopes);
+        }
+
+        return $key;
+    }
+
+    /**
+     * Determine if token is available in the cache, if not call tokenFunc to
+     * fetch it.
+     *
+     * @return string
+     */
+    private function fetchToken()
+    {
+        $cacheKey = $this->getCacheKey();
+        $cached = $this->getCachedValue($cacheKey);
+
+        if (!empty($cached)) {
+            return $cached;
+        }
+
+        $token = call_user_func($this->tokenFunc, $this->scopes);
+        $this->setCachedValue($cacheKey, $token);
+
+        return $token;
+    }
+}

vendor/google/auth/src/Middleware/SimpleMiddleware.php

@@ -0,0 +1,93 @@
+<?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\Middleware;
+
+use GuzzleHttp\Psr7;
+use Psr\Http\Message\RequestInterface;
+
+/**
+ * SimpleMiddleware is a Guzzle Middleware that implements Google's Simple API
+ * access.
+ *
+ * Requests are accessed using the Simple API access developer key.
+ */
+class SimpleMiddleware
+{
+    /**
+     * @var array
+     */
+    private $config;
+
+    /**
+     * Create a new Simple plugin.
+     *
+     * The configuration array expects one option
+     * - key: required, otherwise InvalidArgumentException is thrown
+     *
+     * @param array $config Configuration array
+     */
+    public function __construct(array $config)
+    {
+        if (!isset($config['key'])) {
+            throw new \InvalidArgumentException('requires a key to have been set');
+        }
+
+        $this->config = array_merge(['key' => null], $config);
+    }
+
+    /**
+     * Updates the request query with the developer key if auth is set to simple.
+     *
+     *   use Google\Auth\Middleware\SimpleMiddleware;
+     *   use GuzzleHttp\Client;
+     *   use GuzzleHttp\HandlerStack;
+     *
+     *   $my_key = 'is not the same as yours';
+     *   $middleware = new SimpleMiddleware(['key' => $my_key]);
+     *   $stack = HandlerStack::create();
+     *   $stack->push($middleware);
+     *
+     *   $client = new Client([
+     *       'handler' => $stack,
+     *       'base_uri' => 'https://www.googleapis.com/discovery/v1/',
+     *       'auth' => 'simple'
+     *   ]);
+     *
+     *   $res = $client->get('drive/v2/rest');
+     *
+     * @param callable $handler
+     *
+     * @return \Closure
+     */
+    public function __invoke(callable $handler)
+    {
+        return function (RequestInterface $request, array $options) use ($handler) {
+            // Requests using "auth"="scoped" will be authorized.
+            if (!isset($options['auth']) || $options['auth'] !== 'simple') {
+                return $handler($request, $options);
+            }
+
+            $query = Psr7\parse_query($request->getUri()->getQuery());
+            $params = array_merge($query, $this->config);
+            $uri = $request->getUri()->withQuery(Psr7\build_query($params));
+            $request = $request->withUri($uri);
+
+            return $handler($request, $options);
+        };
+    }
+}

vendor/google/auth/src/Subscriber/AuthTokenSubscriber.php

@@ -0,0 +1,118 @@
+<?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\Subscriber;
+
+use Google\Auth\FetchAuthTokenInterface;
+use GuzzleHttp\Event\BeforeEvent;
+use GuzzleHttp\Event\RequestEvents;
+use GuzzleHttp\Event\SubscriberInterface;
+
+/**
+ * AuthTokenSubscriber is a Guzzle Subscriber that adds an Authorization header
+ * provided by an object implementing FetchAuthTokenInterface.
+ *
+ * The FetchAuthTokenInterface#fetchAuthToken is used to obtain a hash; one of
+ * the values value in that hash is added as the authorization header.
+ *
+ * Requests will be accessed with the authorization header:
+ *
+ * 'Authorization' 'Bearer <value of auth_token>'
+ */
+class AuthTokenSubscriber implements SubscriberInterface
+{
+    /**
+     * @var callable
+     */
+    private $httpHandler;
+
+    /**
+     * @var FetchAuthTokenInterface
+     */
+    private $fetcher;
+
+    /**
+     * @var callable
+     */
+    private $tokenCallback;
+
+    /**
+     * Creates a new AuthTokenSubscriber.
+     *
+     * @param FetchAuthTokenInterface $fetcher is used to fetch the auth token
+     * @param callable $httpHandler (optional) http client to fetch the token.
+     * @param callable $tokenCallback (optional) function to be called when a new token is fetched.
+     */
+    public function __construct(
+        FetchAuthTokenInterface $fetcher,
+        callable $httpHandler = null,
+        callable $tokenCallback = null
+    ) {
+        $this->fetcher = $fetcher;
+        $this->httpHandler = $httpHandler;
+        $this->tokenCallback = $tokenCallback;
+    }
+
+    /**
+     * @return array
+     */
+    public function getEvents()
+    {
+        return ['before' => ['onBefore', RequestEvents::SIGN_REQUEST]];
+    }
+
+    /**
+     * Updates the request with an Authorization header when auth is 'fetched_auth_token'.
+     *
+     *   use GuzzleHttp\Client;
+     *   use Google\Auth\OAuth2;
+     *   use Google\Auth\Subscriber\AuthTokenSubscriber;
+     *
+     *   $config = [..<oauth config param>.];
+     *   $oauth2 = new OAuth2($config)
+     *   $subscriber = new AuthTokenSubscriber($oauth2);
+     *
+     *   $client = new Client([
+     *      'base_url' => 'https://www.googleapis.com/taskqueue/v1beta2/projects/',
+     *      'defaults' => ['auth' => 'google_auth']
+     *   ]);
+     *   $client->getEmitter()->attach($subscriber);
+     *
+     *   $res = $client->get('myproject/taskqueues/myqueue');
+     *
+     * @param BeforeEvent $event
+     */
+    public function onBefore(BeforeEvent $event)
+    {
+        // Requests using "auth"="google_auth" will be authorized.
+        $request = $event->getRequest();
+        if ($request->getConfig()['auth'] != 'google_auth') {
+            return;
+        }
+
+        // Fetch the auth token.
+        $auth_tokens = $this->fetcher->fetchAuthToken($this->httpHandler);
+        if (array_key_exists('access_token', $auth_tokens)) {
+            $request->setHeader('Authorization', 'Bearer ' . $auth_tokens['access_token']);
+
+            // notify the callback if applicable
+            if ($this->tokenCallback) {
+                call_user_func($this->tokenCallback, $this->fetcher->getCacheKey(), $auth_tokens['access_token']);
+            }
+        }
+    }
+}

vendor/google/auth/src/Subscriber/ScopedAccessTokenSubscriber.php

@@ -0,0 +1,177 @@
+<?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\Subscriber;
+
+use Google\Auth\CacheTrait;
+use GuzzleHttp\Event\BeforeEvent;
+use GuzzleHttp\Event\RequestEvents;
+use GuzzleHttp\Event\SubscriberInterface;
+use Psr\Cache\CacheItemPoolInterface;
+
+/**
+ * ScopedAccessTokenSubscriber is a Guzzle Subscriber that adds an Authorization
+ * header provided by a closure.
+ *
+ * The closure returns an access token, taking the scope, either a single
+ * string or an array of strings, as its value.  If provided, a cache will be
+ * used to preserve the access token for a given lifetime.
+ *
+ * Requests will be accessed with the authorization header:
+ *
+ * 'Authorization' 'Bearer <access token obtained from the closure>'
+ */
+class ScopedAccessTokenSubscriber implements SubscriberInterface
+{
+    use CacheTrait;
+
+    const DEFAULT_CACHE_LIFETIME = 1500;
+
+    /**
+     * @var CacheItemPoolInterface
+     */
+    private $cache;
+
+    /**
+     * @var callable The access token generator function
+     */
+    private $tokenFunc;
+
+    /**
+     * @var array|string The scopes used to generate the token
+     */
+    private $scopes;
+
+    /**
+     * @var array
+     */
+    private $cacheConfig;
+
+    /**
+     * Creates a new ScopedAccessTokenSubscriber.
+     *
+     * @param callable $tokenFunc a token generator function
+     * @param array|string $scopes the token authentication scopes
+     * @param array $cacheConfig configuration for the cache when it's present
+     * @param CacheItemPoolInterface $cache an implementation of CacheItemPoolInterface
+     */
+    public function __construct(
+        callable $tokenFunc,
+        $scopes,
+        array $cacheConfig = null,
+        CacheItemPoolInterface $cache = null
+    ) {
+        $this->tokenFunc = $tokenFunc;
+        if (!(is_string($scopes) || is_array($scopes))) {
+            throw new \InvalidArgumentException(
+                'wants scope should be string or array');
+        }
+        $this->scopes = $scopes;
+
+        if (!is_null($cache)) {
+            $this->cache = $cache;
+            $this->cacheConfig = array_merge([
+                'lifetime' => self::DEFAULT_CACHE_LIFETIME,
+                'prefix' => '',
+            ], $cacheConfig);
+        }
+    }
+
+    /**
+     * @return array
+     */
+    public function getEvents()
+    {
+        return ['before' => ['onBefore', RequestEvents::SIGN_REQUEST]];
+    }
+
+    /**
+     * Updates the request with an Authorization header when auth is 'scoped'.
+     *
+     *   E.g this could be used to authenticate using the AppEngine
+     *   AppIdentityService.
+     *
+     *   use google\appengine\api\app_identity\AppIdentityService;
+     *   use Google\Auth\Subscriber\ScopedAccessTokenSubscriber;
+     *   use GuzzleHttp\Client;
+     *
+     *   $scope = 'https://www.googleapis.com/auth/taskqueue'
+     *   $subscriber = new ScopedAccessToken(
+     *       'AppIdentityService::getAccessToken',
+     *       $scope,
+     *       ['prefix' => 'Google\Auth\ScopedAccessToken::'],
+     *       $cache = new Memcache()
+     *   );
+     *
+     *   $client = new Client([
+     *       'base_url' => 'https://www.googleapis.com/taskqueue/v1beta2/projects/',
+     *       'defaults' => ['auth' => 'scoped']
+     *   ]);
+     *   $client->getEmitter()->attach($subscriber);
+     *
+     *   $res = $client->get('myproject/taskqueues/myqueue');
+     *
+     * @param BeforeEvent $event
+     */
+    public function onBefore(BeforeEvent $event)
+    {
+        // Requests using "auth"="scoped" will be authorized.
+        $request = $event->getRequest();
+        if ($request->getConfig()['auth'] != 'scoped') {
+            return;
+        }
+        $auth_header = 'Bearer ' . $this->fetchToken();
+        $request->setHeader('Authorization', $auth_header);
+    }
+
+    /**
+     * @return string
+     */
+    private function getCacheKey()
+    {
+        $key = null;
+
+        if (is_string($this->scopes)) {
+            $key .= $this->scopes;
+        } elseif (is_array($this->scopes)) {
+            $key .= implode(':', $this->scopes);
+        }
+
+        return $key;
+    }
+
+    /**
+     * Determine if token is available in the cache, if not call tokenFunc to
+     * fetch it.
+     *
+     * @return string
+     */
+    private function fetchToken()
+    {
+        $cacheKey = $this->getCacheKey();
+        $cached = $this->getCachedValue($cacheKey);
+
+        if (!empty($cached)) {
+            return $cached;
+        }
+
+        $token = call_user_func($this->tokenFunc, $this->scopes);
+        $this->setCachedValue($cacheKey, $token);
+
+        return $token;
+    }
+}

vendor/google/auth/src/Subscriber/SimpleSubscriber.php

@@ -0,0 +1,90 @@
+<?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\Subscriber;
+
+use GuzzleHttp\Event\BeforeEvent;
+use GuzzleHttp\Event\RequestEvents;
+use GuzzleHttp\Event\SubscriberInterface;
+
+/**
+ * SimpleSubscriber is a Guzzle Subscriber that implements Google's Simple API
+ * access.
+ *
+ * Requests are accessed using the Simple API access developer key.
+ */
+class SimpleSubscriber implements SubscriberInterface
+{
+    /**
+     * @var array
+     */
+    private $config;
+
+    /**
+     * Create a new Simple plugin.
+     *
+     * The configuration array expects one option
+     * - key: required, otherwise InvalidArgumentException is thrown
+     *
+     * @param array $config Configuration array
+     */
+    public function __construct(array $config)
+    {
+        if (!isset($config['key'])) {
+            throw new \InvalidArgumentException('requires a key to have been set');
+        }
+
+        $this->config = array_merge([], $config);
+    }
+
+    /**
+     * @return array
+     */
+    public function getEvents()
+    {
+        return ['before' => ['onBefore', RequestEvents::SIGN_REQUEST]];
+    }
+
+    /**
+     * Updates the request query with the developer key if auth is set to simple.
+     *
+     *   use Google\Auth\Subscriber\SimpleSubscriber;
+     *   use GuzzleHttp\Client;
+     *
+     *   $my_key = 'is not the same as yours';
+     *   $subscriber = new SimpleSubscriber(['key' => $my_key]);
+     *
+     *   $client = new Client([
+     *      'base_url' => 'https://www.googleapis.com/discovery/v1/',
+     *      'defaults' => ['auth' => 'simple']
+     *   ]);
+     *   $client->getEmitter()->attach($subscriber);
+     *
+     *   $res = $client->get('drive/v2/rest');
+     *
+     * @param BeforeEvent $event
+     */
+    public function onBefore(BeforeEvent $event)
+    {
+        // Requests using "auth"="simple" with the developer key.
+        $request = $event->getRequest();
+        if ($request->getConfig()['auth'] != 'simple') {
+            return;
+        }
+        $request->getQuery()->overwriteWith($this->config);
+    }
+}