Add separate upload GZIP flag

Make config GZIP possible to enable separately to the main gzip.
It still defaults to false, but at least in situations like #91 where
it is showing benefit it can be easily enabled.

In order to maintain the defaults though, the config names have become
slightly confusing (one disable, one enable). I've added some constants
to try and work around that, but I may be just setting us up for future
problems!

Author: Ian Barber

src/Google/Config.php

@@ -20,6 +20,10 @@
  */
 class Google_Config
 {
+  const GZIP_DISABLED = true;
+  const GZIP_ENABLED = false;
+  const GZIP_UPLOADS_ENABLED = true;
+  const GZIP_UPLOADS_DISABLED = false;
   const USE_AUTO_IO_SELECTION = "auto";
   private $configuration;
 
@@ -50,8 +54,14 @@ public function __construct($ini_file_location = null)
         // If you want to pass in OAuth 2.0 settings, they will need to be
         // structured like this.
         'Google_Http_Request' => array(
-          // Disable the use of gzip on calls if set to true.
-          'disable_gzip' => false
+          // Disable the use of gzip on calls if set to true. Defaults to false.
+          'disable_gzip' => self::GZIP_ENABLED,
+
+          // We default gzip to disabled on uploads even if gzip is otherwise
+          // enabled, due to some issues seen with small packet sizes for uploads.
+          // Please test with this option before enabling gzip for uploads in
+          // a production environment.
+          'enable_gzip_for_uploads' => self::GZIP_UPLOADS_DISABLED,
         ),
         'Google_Auth_OAuth2' => array(
           // Keys for OAuth 2.0 access, see the API console at
@@ -109,7 +119,7 @@ public function setClassConfig($class, $config, $value = null)
       $this->configuration['classes'][$class] = $config;
     }
   }
-  
+
   public function getClassConfig($class, $key = null)
   {
     if (!isset($this->configuration['classes'][$class])) {
@@ -139,7 +149,7 @@ public function getAuthClass()
   {
     return $this->configuration['auth_class'];
   }
-  
+
   /**
    * Set the auth class.
    *
@@ -155,7 +165,7 @@ public function setAuthClass($class)
     }
     $this->configuration['auth_class'] = $class;
   }
-  
+
   /**
    * Set the IO class.
    *
@@ -268,7 +278,7 @@ public function setApprovalPrompt($approval)
   {
     $this->setAuthConfig('approval_prompt', $approval);
   }
-  
+
   /**
    * Set the developer key for the auth class. Note that this is separate value
    * from the client ID - if it looks like a URL, its a client ID!
@@ -286,7 +296,7 @@ public function getBasePath()
   {
     return $this->configuration['base_path'];
   }
-  
+
   /**
    * Set the auth configuration for the current auth class.
    * @param $key - the key to set

src/Google/Http/MediaFileUpload.php

@@ -51,13 +51,13 @@ class Google_Http_MediaFileUpload
 
   /** @var int $progress */
   private $progress;
-  
+
   /** @var Google_Client */
   private $client;
-  
+
   /** @var Google_Http_Request */
   private $request;
-  
+
   /** @var string */
   private $boundary;
 
@@ -89,7 +89,7 @@ public function __construct(
     $this->chunkSize = $chunkSize;
     $this->progress = 0;
     $this->boundary = $boundary;
-    
+
     // Process Media Request
     $this->process();
   }
@@ -102,16 +102,16 @@ public function setFileSize($size)
   {
     $this->size = $size;
   }
-  
-  /** 
+
+  /**
    * Return the progress on the upload
    * @return int progress in bytes uploaded.
    */
   public function getProgress()
   {
     return $this->progress;
   }
-  
+
   /**
    * Send the next part of the file to upload.
    * @param [$chunk] the next set of bytes to send. If false will used $data passed
@@ -141,7 +141,13 @@ public function nextChunk($chunk = false)
         $headers,
         $chunk
     );
-    $httpRequest->disableGzip(); // Disable gzip for uploads.
+
+    if ($client->getClassConfig("Google_Http_Request", "enable_gzip_for_uploads") {
+      $httpRequest->enableGzip();
+    } else {
+      $httpRequest->disableGzip();
+    }
+
     $response = $this->client->getIo()->makeRequest($httpRequest);
     $response->setExpectedClass($this->request->getExpectedClass());
     $code = $response->getResponseHttpCode();
@@ -150,13 +156,13 @@ public function nextChunk($chunk = false)
       // Track the amount uploaded.
       $range = explode('-', $response->getResponseHeader('range'));
       $this->progress = $range[1] + 1;
-      
+
       // Allow for changing upload URLs.
       $location = $response->getResponseHeader('location');
       if ($location) {
         $this->resumeUri = $location;
       }
-      
+
       // No problems, but upload not complete.
       return false;
     } else {
@@ -177,7 +183,7 @@ private function process()
 
     $meta = $this->request->getPostBody();
     $meta = is_string($meta) ? json_decode($meta, true) : $meta;
-    
+
     $uploadType = $this->getUploadType($meta);
     $this->request->setQueryParam('uploadType', $uploadType);
     $this->transformToUploadUrl();
@@ -214,7 +220,7 @@ private function process()
       $this->request->setRequestHeaders($contentTypeHeader);
     }
   }
-  
+
   private function transformToUploadUrl()
   {
     $base = $this->request->getBaseComponent();