resolved #159

Author: sinkcup

src/Qiniu/Storage/BucketManager.php

@@ -208,7 +208,7 @@ public function changeMime($bucket, $key, $mime)
      *                                  ]
      * @link  http://developer.qiniu.com/docs/v6/api/reference/rs/fetch.html
      */
-    public function fetch($url, $bucket, $key)
+    public function fetch($url, $bucket, $key = null)
     {
 
         $resource = \Qiniu\base64_urlSafeEncode($url);

tests/Qiniu/Tests/BucketTest.php

@@ -131,6 +131,13 @@ public function testFetch()
         );
         $this->assertArrayHasKey('key', $ret);
         $this->assertNull($error);
+ 
+        list($ret, $error) = $this->bucketManager->fetch(
+            'http://developer.qiniu.com/docs/v6/sdk/php-sdk.html',
+            $this->bucketName
+        );
+        $this->assertArrayHasKey('key', $ret);
+        $this->assertNull($error);
     }
 
     public function testBatchCopy()