chore($httpBackend): preserve original non-zero http status code for file:// apps

Previously if an app was running from file:// origin we would always return either
http 200 or 404 depending on whether the response was present.

This changes the behavior so that we do this only if the protocol of the request
(not the origin) is file:// and only if the status code is 0.

Closes #4436
Closes #4587
Closes #4514

src/ng/httpBackend.js

@@ -28,12 +28,11 @@ var XHR = window.XMLHttpRequest || function() {
  */
 function $HttpBackendProvider() {
   this.$get = ['$browser', '$window', '$document', function($browser, $window, $document) {
-    return createHttpBackend($browser, XHR, $browser.defer, $window.angular.callbacks,
-        $document[0], $window.location.protocol.replace(':', ''));
+    return createHttpBackend($browser, XHR, $browser.defer, $window.angular.callbacks, $document[0]);
   }];
 }
 
-function createHttpBackend($browser, XHR, $browserDefer, callbacks, rawDocument, locationProtocol) {
+function createHttpBackend($browser, XHR, $browserDefer, callbacks, rawDocument) {
   var ABORTED = -1;
 
   // TODO(vojta): fix the signature
@@ -113,14 +112,14 @@ function createHttpBackend($browser, XHR, $browserDefer, callbacks, rawDocument,
     }
 
     function completeRequest(callback, status, response, headersString) {
-      var protocol = locationProtocol || urlResolve(url).protocol;
+      var protocol = urlResolve(url).protocol;
 
       // cancel timeout and subsequent timeout promise resolution
       timeoutId && $browserDefer.cancel(timeoutId);
       jsonpDone = xhr = null;
 
       // fix status code for file protocol (it's always 0)
-      status = (protocol == 'file') ? (response ? 200 : 404) : status;
+      status = (protocol == 'file' && status === 0) ? (response ? 200 : 404) : status;
 
       // normalize IE bug (http://bugs.jquery.com/ticket/1450)
       status = status == 1223 ? 204 : status;

test/ng/httpBackendSpec.js

@@ -436,13 +436,61 @@ describe('$httpBackend', function() {
 
 
     it('should convert 0 to 404 if no content - relative url', function() {
-      $backend = createHttpBackend($browser, MockXhr, null, null, null, 'file');
+      var originalUrlParsingNode = urlParsingNode;
 
-      $backend('GET', '/whatever/index.html', null, callback);
-      respond(0, '');
+      //temporarily overriding the DOM element to pretend that the test runs origin with file:// protocol
+      urlParsingNode = {
+        hash : "#/C:/",
+        host : "",
+        hostname : "",
+        href : "file:///C:/base#!/C:/foo",
+        pathname : "/C:/foo",
+        port : "",
+        protocol : "file:",
+        search : "",
+        setAttribute: angular.noop
+      };
+
+      try {
+
+        $backend = createHttpBackend($browser, MockXhr);
+
+        $backend('GET', '/whatever/index.html', null, callback);
+        respond(0, '');
+
+        expect(callback).toHaveBeenCalled();
+        expect(callback.mostRecentCall.args[0]).toBe(404);
+
+      } finally {
+        urlParsingNode = originalUrlParsingNode;
+      }
+    });
+
+
+    it('should return original backend status code if different from 0', function () {
+      $backend = createHttpBackend($browser, MockXhr);
+
+      // request to http://
+      $backend('POST', 'http://rest_api/create_whatever', null, callback);
+      respond(201, '');
 
       expect(callback).toHaveBeenCalled();
-      expect(callback.mostRecentCall.args[0]).toBe(404);
+      expect(callback.mostRecentCall.args[0]).toBe(201);
+
+
+      // request to file://
+      $backend('POST', 'file://rest_api/create_whatever', null, callback);
+      respond(201, '');
+
+      expect(callback).toHaveBeenCalled();
+      expect(callback.mostRecentCall.args[0]).toBe(201);
+
+      // request to file:// with HTTP status >= 300
+      $backend('POST', 'file://rest_api/create_whatever', null, callback);
+      respond(503, '');
+
+      expect(callback).toHaveBeenCalled();
+      expect(callback.mostRecentCall.args[0]).toBe(503);
     });
   });
 });