feat(service): add withHttpConfig to objects created with .service

* Replacement for PR #1068 (#1392)

* First test for #1068

* Added doc

Author: madflow

README.md

@@ -672,7 +672,8 @@ app.controller('MainCtrl', function(Restangular, BingRestangular) {
 
 ### Decoupled Restangular Service
 
-There're some times where you want to use Restangular but you don't want to expose Restangular object anywhere. For those cases, you can actually use the `service` feature of Restangular.
+There're some times where you want to use Restangular but you don't want to expose Restangular object anywhere. 
+For those cases, you can actually use the `service` feature of Restangular.
 
 Let's see how it works:
 
@@ -695,6 +696,21 @@ Users.getList().then(function(users) {
 })
 ````
 
+You can also use ```withHttpConfig``` on objects created by ```Restangular.service```.
+
+```js
+var personService = Restangular.service('person');
+var entity = personService.withHttpConfig({transformRequest: function(data) {
+  data.fullname = data.firstname + ' ' + data.lastname;
+  return JSON.stringify(data);
+}}).post({
+  "lastname": "Mueller",
+  "firstname": "Gerd"
+}).then(function(resp) {
+    console.log(resp);
+});
+```
+
 We can also use Nested RESTful resources with this:
 
 ````js

src/restangular.js

@@ -1335,6 +1335,7 @@ restangular.provider('Restangular', function() {
         serv.one = _.bind(one, (parent || service), parent, route);
         serv.post = _.bind(collection.post, collection);
         serv.getList = _.bind(collection.getList, collection);
+        serv.withHttpConfig = _.bind(collection.withHttpConfig, collection);
 
         for (var prop in collection) {
           if (collection.hasOwnProperty(prop) && _.isFunction(collection[prop]) && !_.includes(knownCollectionMethods, prop)) {

test/restangularSpec.js

@@ -709,6 +709,15 @@ describe("Restangular", function() {
       $httpBackend.expectGET('/accounts/do-something');
       $httpBackend.flush();
     });
+
+    it("should provide a one-off $http configuration method", function() {
+      var Accounts = Restangular.service('accounts');
+      Accounts.withHttpConfig({transformRequest: angular.identity});
+      Accounts.post(newAccount);
+      $httpBackend.expectPOST('/accounts');
+      $httpBackend.flush();
+    });
+
   });
 
   describe("ONE", function() {