Allow for valid cross client authentication requests

Author: tehmaestro

src/Google/Auth/OAuth2.php

@@ -78,28 +78,34 @@ public function authenticatedRequest(Google_Http_Request $request)
 
   /**
    * @param string $code
+   * @param boolean $crossClient
    * @throws Google_Auth_Exception
    * @return string
    */
-  public function authenticate($code)
+  public function authenticate($code, $crossClient)
   {
     if (strlen($code) == 0) {
       throw new Google_Auth_Exception("Invalid code");
     }
 
+    $arguments = array(
+          'code' => $code,
+          'grant_type' => 'authorization_code',
+          'client_id' => $this->client->getClassConfig($this, 'client_id'),
+          'client_secret' => $this->client->getClassConfig($this, 'client_secret')
+    );
+
+    if($crossClient !== true) {
+        $arguments['redirect_uri'] = $this->client->getClassConfig($this, 'redirect_uri');
+    }
+
     // We got here from the redirect from a successful authorization grant,
     // fetch the access token
     $request = new Google_Http_Request(
         self::OAUTH2_TOKEN_URI,
         'POST',
         array(),
-        array(
-          'code' => $code,
-          'grant_type' => 'authorization_code',
-          'redirect_uri' => $this->client->getClassConfig($this, 'redirect_uri'),
-          'client_id' => $this->client->getClassConfig($this, 'client_id'),
-          'client_secret' => $this->client->getClassConfig($this, 'client_secret')
-        )
+        $arguments
     );
     $request->disableGzip();
     $response = $this->client->getIo()->makeRequest($request);

src/Google/Client.php

@@ -114,15 +114,18 @@ public function getLibraryVersion()
 
   /**
    * Attempt to exchange a code for an valid authentication token.
+   * If $crossClient is set to true, the request body will not include
+   * the request_uri argument
    * Helper wrapped around the OAuth 2.0 implementation.
    *
    * @param $code string code from accounts.google.com
+   * @param $crossIdentity boolean, whether this is a cross-client authentication
    * @return string token
    */
-  public function authenticate($code)
+  public function authenticate($code, $crossClient = false)
   {
     $this->authenticated = true;
-    return $this->getAuth()->authenticate($code);
+    return $this->getAuth()->authenticate($code, $crossClient);
   }
 
   /**