diff --git a/workflow/engine/classes/class.pmDrive.php b/workflow/engine/classes/class.pmDrive.php
index e271d4de0..56fa06b2b 100755
--- a/workflow/engine/classes/class.pmDrive.php
+++ b/workflow/engine/classes/class.pmDrive.php
@@ -94,12 +94,13 @@ class PMDrive extends PMGoogleApi
      */
     public function listFolder($fileId)
     {
-        $this->setScope('https://www.googleapis.com/auth/drive');
-        $this->setScope('https://www.googleapis.com/auth/drive.file');
-        $this->setScope('https://www.googleapis.com/auth/drive.readonly');
-        $this->setScope('https://www.googleapis.com/auth/drive.metadata.readonly');
-        $this->setScope('https://www.googleapis.com/auth/drive.appdata');
-        $this->setScope('https://www.googleapis.com/auth/drive.metadata');
+        $this->setScope(static::DRIVE);
+        $this->setScope(static::DRIVE_FILE);
+        $this->setScope(static::DRIVE_READONLY);
+        $this->setScope(static::DRIVE_METADATA);
+        $this->setScope(static::DRIVE_METADATA_READONLY);
+        $this->setScope(static::DRIVE_APPDATA);
+        
         $service = $this->serviceDrive();
 
         try {
@@ -126,7 +127,7 @@ class PMDrive extends PMGoogleApi
      */
     public function createFolder($name, $parentId = null)
     {
-        $this->setScope('https://www.googleapis.com/auth/drive.file');
+        $this->setScope(static::DRIVE_FILE);
 
         $service = $this->serviceDrive();
 
@@ -159,7 +160,7 @@ class PMDrive extends PMGoogleApi
      */
     public function uploadFile($mime, $src, $name, $parentId = null)
     {
-        $this->setScope('https://www.googleapis.com/auth/drive.file');
+        $this->setScope(static::DRIVE_FILE);
 
         $service = $this->serviceDrive();
 
@@ -200,13 +201,13 @@ class PMDrive extends PMGoogleApi
      */
     public function downloadFile($fileId)
     {
-        $this->setScope('https://www.googleapis.com/auth/drive');
-        $this->setScope('https://www.googleapis.com/auth/drive.appdata');
-        $this->setScope('https://www.googleapis.com/auth/drive.apps.readonly');
-        $this->setScope('https://www.googleapis.com/auth/drive.file');
-        $this->setScope('https://www.googleapis.com/auth/drive.metadata');
-        $this->setScope('https://www.googleapis.com/auth/drive.metadata.readonly');
-        $this->setScope('https://www.googleapis.com/auth/drive.readonly');
+        $this->setScope(static::DRIVE);
+        $this->setScope(static::DRIVE_APPDATA);
+        $this->setScope(static::DRIVE_APPS_READONLY);
+        $this->setScope(static::DRIVE_FILE);
+        $this->setScope(static::DRIVE_METADATA);
+        $this->setScope(static::DRIVE_METADATA_READONLY);
+        $this->setScope(static::DRIVE_READONLY);
         $service = $this->serviceDrive();
         $response = null;
 
@@ -241,8 +242,8 @@ class PMDrive extends PMGoogleApi
      */
     public function setPermission($fileId, $value, $type = 'user', $role = 'reader', $sendNotification = false)
     {
-        $this->setScope('https://www.googleapis.com/auth/drive');
-        $this->setScope('https://www.googleapis.com/auth/drive.file');
+        $this->setScope(static::DRIVE);
+        $this->setScope(static::DRIVE_FILE);
 
         $service = $this->serviceDrive();
 
diff --git a/workflow/engine/classes/class.pmGoogleApi.php b/workflow/engine/classes/class.pmGoogleApi.php
index 89426007a..8d7d72c0a 100755
--- a/workflow/engine/classes/class.pmGoogleApi.php
+++ b/workflow/engine/classes/class.pmGoogleApi.php
@@ -9,6 +9,15 @@ require_once PATH_TRUNK . 'vendor' . PATH_SEP . 'google' . PATH_SEP . 'apiclient
 
 class PMGoogleApi
 {
+    const DRIVE = 'https://www.googleapis.com/auth/drive';
+    const DRIVE_FILE = 'https://www.googleapis.com/auth/drive.file';
+    const DRIVE_APPS_READONLY = 'https://www.googleapis.com/auth/drive.apps.readonly';
+    const DRIVE_READONLY = 'https://www.googleapis.com/auth/drive.readonly';
+    const DRIVE_METADATA = 'https://www.googleapis.com/auth/drive.metadata';
+    const DRIVE_METADATA_READONLY = 'https://www.googleapis.com/auth/drive.metadata.readonly';
+    const DRIVE_APPDATA = 'https://www.googleapis.com/auth/drive.appdata';
+    const DRIVE_PHOTOS_READONLY = 'https://www.googleapis.com/auth/drive.photos.readonly';
+
     private $scope = array();
     private $serviceAccountEmail;
     private $serviceAccountP12;
@@ -244,13 +253,13 @@ class PMGoogleApi
     {
 
         $scope = array(
-            'https://www.googleapis.com/auth/drive',
-            'https://www.googleapis.com/auth/drive.file',
-            'https://www.googleapis.com/auth/drive.readonly',
-            'https://www.googleapis.com/auth/drive.metadata.readonly',
-            'https://www.googleapis.com/auth/drive.appdata',
-            'https://www.googleapis.com/auth/drive.metadata',
-            'https://www.googleapis.com/auth/drive.photos.readonly'
+            static::DRIVE,
+            static::DRIVE_FILE,
+            static::DRIVE_READONLY,
+            static::DRIVE_METADATA,
+            static::DRIVE_METADATA_READONLY,
+            static::DRIVE_APPDATA,
+            static::DRIVE_PHOTOS_READONLY
         );
 
         if ($credentials->typeAuth == 'webApplication') {