fix($http): honor application/json response header and parse json primitives

When server responds with Content-Type header set to application/json we now properly parse the response as JSON

Closes angular#2973

Author: IgorMinar

src/ng/http.js

@@ -89,7 +89,8 @@ function $HttpProvider() {
   var JSON_START = /^\s*(\[|\{[^\{])/,
       JSON_END = /[\}\]]\s*$/,
       PROTECTION_PREFIX = /^\)\]\}',?\n/,
-      CONTENT_TYPE_APPLICATION_JSON = {'Content-Type': 'application/json;charset=utf-8'};
+      APPLICATION_JSON = 'application/json',
+      CONTENT_TYPE_APPLICATION_JSON = {'Content-Type': APPLICATION_JSON + ';charset=utf-8'};
 
   /**
    * @ngdoc property
@@ -114,12 +115,15 @@ function $HttpProvider() {
    **/
   var defaults = this.defaults = {
     // transform incoming response data
-    transformResponse: [function(data) {
+    transformResponse: [function defaultHttpResponseTransform(data, headers) {
       if (isString(data)) {
         // strip json vulnerability protection prefix
         data = data.replace(PROTECTION_PREFIX, '');
-        if (JSON_START.test(data) && JSON_END.test(data))
+        var contentType = headers('Content-Type');
+        if ((contentType && contentType.indexOf(APPLICATION_JSON) === 0) ||
+            (JSON_START.test(data) && JSON_END.test(data))) {
           data = fromJson(data);
+        }
       }
       return data;
     }],

test/ng/httpSpec.js

@@ -1020,6 +1020,61 @@ describe('$http', function() {
           });
 
 
+          it('should deserialize json numbers when response header contains application/json',
+              function() {
+            $httpBackend.expect('GET', '/url').respond('123', {'Content-Type': 'application/json'});
+            $http({method: 'GET', url: '/url'}).success(callback);
+            $httpBackend.flush();
+
+            expect(callback).toHaveBeenCalledOnce();
+            expect(callback.mostRecentCall.args[0]).toEqual(123);
+          });
+
+
+          it('should deserialize json strings when response header contains application/json',
+              function() {
+            $httpBackend.expect('GET', '/url').respond('"asdf"', {'Content-Type': 'application/json'});
+            $http({method: 'GET', url: '/url'}).success(callback);
+            $httpBackend.flush();
+
+            expect(callback).toHaveBeenCalledOnce();
+            expect(callback.mostRecentCall.args[0]).toEqual('asdf');
+          });
+
+
+          it('should deserialize json nulls when response header contains application/json',
+              function() {
+            $httpBackend.expect('GET', '/url').respond('null', {'Content-Type': 'application/json'});
+            $http({method: 'GET', url: '/url'}).success(callback);
+            $httpBackend.flush();
+
+            expect(callback).toHaveBeenCalledOnce();
+            expect(callback.mostRecentCall.args[0]).toEqual(null);
+          });
+
+
+          it('should deserialize json true when response header contains application/json',
+              function() {
+            $httpBackend.expect('GET', '/url').respond('true', {'Content-Type': 'application/json'});
+            $http({method: 'GET', url: '/url'}).success(callback);
+            $httpBackend.flush();
+
+            expect(callback).toHaveBeenCalledOnce();
+            expect(callback.mostRecentCall.args[0]).toEqual(true);
+          });
+
+
+          it('should deserialize json false when response header contains application/json',
+              function() {
+            $httpBackend.expect('GET', '/url').respond('false', {'Content-Type': 'application/json'});
+            $http({method: 'GET', url: '/url'}).success(callback);
+            $httpBackend.flush();
+
+            expect(callback).toHaveBeenCalledOnce();
+            expect(callback.mostRecentCall.args[0]).toEqual(false);
+          });
+
+
           it('should deserialize json with security prefix', function() {
             $httpBackend.expect('GET', '/url').respond(')]}\',\n[1, "abc", {"foo":"bar"}]');
             $http({method: 'GET', url: '/url'}).success(callback);