Added XSRF prevention logic to $xhr service

CHANGELOG.md

@@ -1,6 +1,10 @@
 <a name="0.9.13"><a/>
 # <angular/> 0.9.13 curdling-stare (in-progress) #
 
+### New Features
+- Added XSRF prevention logic to $xhr service
+
+
 ### Bug Fixes
 - Fixed cookies which contained unescaped '=' would not show up in cookie service.
 - Consider all 2xx responses as OK, not just 200

src/Browser.js

@@ -7,6 +7,11 @@ var XHR = window.XMLHttpRequest || function () {
   try { return new ActiveXObject("Msxml2.XMLHTTP"); } catch (e3) {}
   throw new Error("This browser does not support XMLHttpRequest.");
 };
+var XHR_HEADERS = {
+  "Content-Type": "application/x-www-form-urlencoded",
+  "Accept": "application/json, text/plain, */*",
+  "X-Requested-With": "XMLHttpRequest"
+};
 
 /**
  * @private
@@ -72,11 +77,18 @@ function Browser(window, document, body, XHR, $log) {
    * @param {string} url Requested url
    * @param {?string} post Post data to send (null if nothing to post)
    * @param {function(number, string)} callback Function that will be called on response
+   * @param {object=} header additional HTTP headers to send with XHR.
+   *   Standard headers are:
+   *   <ul>
+   *     <li><tt>Content-Type</tt>: <tt>application/x-www-form-urlencoded</tt></li>
+   *     <li><tt>Accept</tt>: <tt>application/json, text/plain, &#42;/&#42;</tt></li>
+   *     <li><tt>X-Requested-With</tt>: <tt>XMLHttpRequest</tt></li>
+   *   </ul>
    *
    * @description
    * Send ajax request
    */
-  self.xhr = function(method, url, post, callback) {
+  self.xhr = function(method, url, post, callback, headers) {
     outstandingRequestCount ++;
     if (lowercase(method) == 'json') {
       var callbackId = "angular_" + Math.random() + '_' + (idCounter++);
@@ -92,9 +104,9 @@ function Browser(window, document, body, XHR, $log) {
     } else {
       var xhr = new XHR();
       xhr.open(method, url, true);
-      xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
-      xhr.setRequestHeader("Accept", "application/json, text/plain, */*");
-      xhr.setRequestHeader("X-Requested-With", "XMLHttpRequest");
+      forEach(extend(XHR_HEADERS, headers || {}), function(value, key){
+        if (value) xhr.setRequestHeader(key, value);
+      });
       xhr.onreadystatechange = function() {
         if (xhr.readyState == 4) {
           completeOutstandingRequest(callback, xhr.status || 200, xhr.responseText);

src/angular-mocks.js

@@ -101,28 +101,27 @@ function MockBrowser() {
   };
 
 
-  self.xhr = function(method, url, data, callback) {
-    if (angular.isFunction(data)) {
-      callback = data;
-      data = null;
-    }
+  self.xhr = function(method, url, data, callback, headers) {
+    headers = headers || {};
     if (data && angular.isObject(data)) data = angular.toJson(data);
     if (data && angular.isString(data)) url += "|" + data;
     var expect = expectations[method] || {};
-    var response = expect[url];
-    if (!response) {
-      throw {
-        message: "Unexpected request for method '" + method + "' and url '" + url + "'.",
-        name: "Unexpected Request"
-      };
+    var expectation = expect[url];
+    if (!expectation) {
+      throw new Error("Unexpected request for method '" + method + "' and url '" + url + "'.");
     }
     requests.push(function(){
-      callback(response.code, response.response);
+      forEach(expectation.headers, function(value, key){
+        if (headers[key] !== value) {
+          throw new Error("Missing HTTP request header: " + key + ": " + value);
+        }
+      });
+      callback(expectation.code, expectation.response);
     });
   };
   self.xhr.expectations = expectations;
   self.xhr.requests = requests;
-  self.xhr.expect = function(method, url, data) {
+  self.xhr.expect = function(method, url, data, headers) {
     if (data && angular.isObject(data)) data = angular.toJson(data);
     if (data && angular.isString(data)) url += "|" + data;
     var expect = expectations[method] || (expectations[method] = {});
@@ -132,7 +131,7 @@ function MockBrowser() {
           response = code;
           code = 200;
         }
-        expect[url] = {code:code, response:response};
+        expect[url] = {code:code, response:response, headers: headers || {}};
       }
     };
   };

src/service/xhr.js

@@ -3,13 +3,71 @@
  * @ngdoc service
  * @name angular.service.$xhr
  * @function
- * @requires $browser
- * @requires $xhr.error
- * @requires $log
+ * @requires $browser $xhr delegates all XHR requests to the `$browser.xhr()`. A mock version
+ *                    of the $browser exists which allows setting expectaitions on XHR requests
+ *                    in your tests
+ * @requires $xhr.error $xhr delegates all non `2xx` response code to this service.
+ * @requires $log $xhr delegates all exceptions to `$log.error()`.
+ * @requires $updateView After a server response the view needs to be updated for data-binding to
+ *           take effect.
  *
  * @description
- * Generates an XHR request. The $xhr service adds error handling then delegates all requests to
- * {@link angular.service.$browser $browser.xhr()}.
+ * Generates an XHR request. The $xhr service delegates all requests to
+ * {@link angular.service.$browser $browser.xhr()} and adds error handling and security features.
+ * While $xhr service provides nicer api than raw XmlHttpRequest, it is still considered a lower
+ * level api in angular. For a higher level abstraction that utilizes `$xhr`, please check out the
+ * {@link angular.service$resource $resource} service.
+ *
+ * # Error handling
+ * All XHR responses with response codes other then `2xx` are delegated to
+ * {@link angular.service.$xhr.error $xhr.error}. The `$xhr.error` can intercept the request
+ * and process it in application specific way, or resume normal execution by calling the
+ * request callback method.
+ *
+ * # Security Considerations
+ * When designing web applications your design needs to consider security threats from
+ * {@link http://haacked.com/archive/2008/11/20/anatomy-of-a-subtle-json-vulnerability.aspx
+ * JSON Vulnerability} and {@link http://en.wikipedia.org/wiki/Cross-site_request_forgery XSRF}.
+ * Both server and the client must cooperate in order to eliminate these threats. Angular comes
+ * pre-configured with strategies that address these issues, but for this to work backend server
+ * cooperation is required.
+ *
+ * ## JSON Vulnerability Protection
+ * A {@link http://haacked.com/archive/2008/11/20/anatomy-of-a-subtle-json-vulnerability.aspx
+ * JSON Vulnerability} allows third party web-site to turn your JSON resource URL into
+ * {@link http://en.wikipedia.org/wiki/JSON#JSONP JSONP} request under some conditions. To
+ * counter this your server can prefix all JSON requests with following string `")]}',\n"`.
+ * Angular will automatically strip the prefix before processing it as JSON.
+ *
+ * For example if your server needs to return:
+ * <pre>
+ * ['one','two']
+ * </pre>
+ *
+ * which is vulnerable to attack, your server can return:
+ * <pre>
+ * )]}',
+ * ['one','two']
+ * </pre>
+ *
+ * angular will strip the prefix, before processing the JSON.
+ *
+ *
+ * ## Cross Site Request Forgery (XSRF) Protection
+ * {@link http://en.wikipedia.org/wiki/Cross-site_request_forgery XSRF} is a technique by which an
+ * unauthorized site can gain your user's private data. Angular provides following mechanism to
+ * counter XSRF. When performing XHR requests, the $xhr service reads a token from a cookie
+ * called `XSRF-TOKEN` and sets it as the HTTP header `X-XSRF-TOKEN`. Since only JavaScript that
+ * runs on your domain could read the cookie, your server can be assured that the XHR came from
+ * JavaScript running on your domain.
+ *
+ * To take advantage of this, your server needs to set a token in a JavaScript readable session
+ * cookie called `XSRF-TOKEN` on first HTTP GET request. On subsequent non-GET requests the server
+ * can verify that the cookie matches `X-XSRF-TOKEN` HTTP header, and therefore be sure that only
+ * JavaScript running on your domain could have read the token. The token must be unique for each
+ * user and must be verifiable by  the server (to prevent the JavaScript making up its own tokens).
+ * We recommend that the token is a digest of your site's authentication cookie with
+ * {@link http://en.wikipedia.org/wiki/Rainbow_table salt for added security}.
  *
  * @param {string} method HTTP method to use. Valid values are: `GET`, `POST`, `PUT`, `DELETE`, and
  *   `JSON`. `JSON` is a special case which causes a
@@ -67,8 +125,7 @@
      </doc:source>
    </doc:example>
  */
-angularServiceInject('$xhr', function($browser, $error, $log){
-  var self = this;
+angularServiceInject('$xhr', function($browser, $error, $log, $updateView){
   return function(method, url, post, callback){
     if (isFunction(post)) {
       callback = post;
@@ -77,6 +134,7 @@ angularServiceInject('$xhr', function($browser, $error, $log){
     if (post && isObject(post)) {
       post = toJson(post);
     }
+
     $browser.xhr(method, url, post, function(code, response){
       try {
         if (isString(response)) {
@@ -95,8 +153,10 @@ angularServiceInject('$xhr', function($browser, $error, $log){
       } catch (e) {
         $log.error(e);
       } finally {
-        self.$eval();
+        $updateView();
       }
+    }, {
+        'X-XSRF-TOKEN': $browser.cookies()['XSRF-TOKEN']
     });
   };
-}, ['$browser', '$xhr.error', '$log']);
+}, ['$browser', '$xhr.error', '$log', '$updateView']);

test/BrowserSpecs.js

@@ -24,11 +24,20 @@ describe('browser', function(){
 
     var fakeBody = {append: function(node){scripts.push(node);}};
 
-    var fakeXhr = function(){
+    var FakeXhr = function(){
       xhr = this;
-      this.open = noop;
-      this.setRequestHeader = noop;
-      this.send = noop;
+      this.open = function(method, url, async){
+        xhr.method = method;
+        xhr.url = url;
+        xhr.async = async;
+        xhr.headers = {};
+      };
+      this.setRequestHeader = function(key, value){
+        xhr.headers[key] = value;
+      };
+      this.send = function(post){
+        xhr.post = post;
+      };
     };
 
     logs = {log:[], warn:[], info:[], error:[]};
@@ -38,7 +47,7 @@ describe('browser', function(){
                    info: function() { logs.info.push(slice.call(arguments)); },
                    error: function() { logs.error.push(slice.call(arguments)); }};
 
-    browser = new Browser(fakeWindow, jqLite(window.document), fakeBody, fakeXhr,
+    browser = new Browser(fakeWindow, jqLite(window.document), fakeBody, FakeXhr,
                           fakeLog);
   });
 
@@ -85,6 +94,33 @@ describe('browser', function(){
         expect(typeof fakeWindow[url[1]]).toEqual('undefined');
       });
     });
+
+    it('should set headers for all requests', function(){
+      var code, response, headers = {};
+      browser.xhr('METHOD', 'URL', 'POST', function(c,r){
+        code = c;
+        response = r;
+      }, {'X-header': 'value'});
+
+      expect(xhr.method).toEqual('METHOD');
+      expect(xhr.url).toEqual('URL');
+      expect(xhr.post).toEqual('POST');
+      expect(xhr.headers).toEqual({
+        "Content-Type": "application/x-www-form-urlencoded",
+        "Accept": "application/json, text/plain, */*",
+        "X-Requested-With": "XMLHttpRequest",
+        "X-header":"value"
+      });
+
+      xhr.status = 202;
+      xhr.responseText = 'RESPONSE';
+      xhr.readyState = 4;
+      xhr.onreadystatechange();
+
+      expect(code).toEqual(202);
+      expect(response).toEqual('RESPONSE');
+    });
+
   });
 
 

test/service/xhrSpec.js

@@ -101,4 +101,21 @@ describe('$xhr', function() {
 
     expect(response).toEqual([1, 'abc', {foo:'bar'}]);
   });
+
+  describe('xsrf', function(){
+    it('should copy the XSRF cookie into a XSRF Header', function(){
+      var code, response;
+      $browserXhr
+        .expectPOST('URL', 'DATA', {'X-XSRF-TOKEN': 'secret'})
+        .respond(234, 'OK');
+      $browser.cookies('XSRF-TOKEN', 'secret');
+      $xhr('POST', 'URL', 'DATA', function(c, r){
+        code = c;
+        response = r;
+      });
+      $browserXhr.flush();
+      expect(code).toEqual(234);
+      expect(response).toEqual('OK');
+    });
+  });
 });