storage: add support for generation on getSignedUrl

Author: simonfan

lib/storage/file.js

@@ -1173,6 +1173,7 @@ File.prototype.getSignedUrl = function(options, callback) {
   }[options.action];
 
   var name = encodeURIComponent(this.name);
+  var targetGeneration = this.generation;
 
   options.resource = '/' + this.bucket.name + '/' + name;
 
@@ -1221,13 +1222,19 @@ File.prototype.getSignedUrl = function(options, callback) {
         encodeURIComponent(options.responseDisposition);
     }
 
+    var generation = '';
+    if (!is.undefined(targetGeneration)) {
+      generation = '&generation=' + targetGeneration;
+    }
+
     callback(null, [
       'https://storage.googleapis.com' + options.resource,
       '?GoogleAccessId=' + credentials.client_email,
       '&Expires=' + expiresInSeconds,
       '&Signature=' + encodeURIComponent(signature),
       responseContentType,
-      responseContentDisposition
+      responseContentDisposition,
+      generation
     ].join(''));
   });
 };

test/storage/file.js

@@ -1749,6 +1749,18 @@ describe('File', function() {
       });
     });
 
+    it('should add generation parameter', function(done) {
+      var generation = 10003320000;
+      var file = new File(BUCKET, 'name', { generation: generation });
+      file.getSignedUrl({
+        action: 'read',
+        expires: Date.now() + 5,
+      }, function(err, signedUrl) {
+        assert(signedUrl.indexOf(encodeURIComponent(generation)) > -1);
+        done();
+      });
+    });
+
     describe('promptSaveAs', function() {
       it('should add response-content-disposition', function(done) {
         var disposition = 'attachment; filename="fname.ext"';