feat($http): setting JSONP callback name

Author: ricardohbin

src/ng/httpBackend.js

@@ -38,12 +38,17 @@ function createHttpBackend($browser, XHR, $browserDefer, callbacks, rawDocument,
     url = url || $browser.url();
 
     if (lowercase(method) == 'jsonp') {
-      var callbackId = '_' + (callbacks.counter++).toString(36);
+      var callbackId = (/JSON_CALLBACK\((.*)\)/).exec(url) || ('_' + (callbacks.counter++).toString(36));
+      
+      if (callbackId.constructor.name === "Array") {
+        callbackId = callbackId[1];
+      }
+
       callbacks[callbackId] = function(data) {
         callbacks[callbackId].data = data;
       };
-
-      var jsonpDone = jsonpReq(url.replace('JSON_CALLBACK', 'angular.callbacks.' + callbackId),
+      
+      var jsonpDone = jsonpReq(url.replace(/JSON_CALLBACK\((.*)\)|JSON_CALLBACK/, 'angular.callbacks.' + callbackId),
           function() {
         if (callbacks[callbackId].data) {
           completeRequest(callback, 200, callbacks[callbackId].data);

test/ng/httpBackendSpec.js

@@ -327,6 +327,14 @@ describe('$httpBackend', function() {
       expect(callback).toHaveBeenCalledOnce();
     });
 
+    it('should set the callback name when use JSONP_CALLBACK with a parameter', function() {
+      $backend('JSONP', 'http://example.org/path?cb=JSON_CALLBACK(someCallback)', null, callback);
+      var script = fakeDocument.$$scripts.shift(),
+          url = script.src.match(SCRIPT_URL);
+
+      expect(url[1]).toBe('http://example.org/path');
+      expect(url[2]).toBe('someCallback');
+    });
 
     // TODO(vojta): test whether it fires "async-start"
     // TODO(vojta): test whether it fires "async-end" on both success and error