feat($resource): support custom headers per action

Closes #736

src/ngResource/resource.js

@@ -36,8 +36,8 @@
  * @param {Object.<Object>=} actions Hash with declaration of custom action that should extend the
  *   default set of resource actions. The declaration should be created in the following format:
  *
- *       {action1: {method:?, params:?, isArray:?},
- *        action2: {method:?, params:?, isArray:?},
+ *       {action1: {method:?, params:?, isArray:?, headers:?},
+ *        action2: {method:?, params:?, isArray:?, headers:?},
  *        ...}
  *
  *   Where:
@@ -49,6 +49,7 @@
  *   - `params` – {object=} – Optional set of pre-bound parameters for this action.
  *   - isArray – {boolean=} – If true then the returned object for this action is an array, see
  *     `returns` section.
+ *   - `headers` – {object=} – Optional HTTP headers to send
  *
  * @returns {Object} A resource "class" object with methods for the default set of resource actions
  *   optionally extended with custom `actions`. The default set contains these actions:
@@ -130,7 +131,7 @@
  * The object returned from this function execution is a resource "class" which has "static" method
  * for each action in the definition.
  *
- * Calling these methods invoke `$http` on the `url` template with the given `method` and `params`.
+ * Calling these methods invoke `$http` on the `url` template with the given `method`, `params` and `headers`.
  * When the data is returned from the server then the object is an instance of the resource type and
  * all of the non-GET methods are available with `$` prefix. This allows you to easily support CRUD
  * operations (create, read, update, delete) on server-side data.
@@ -362,7 +363,8 @@ angular.module('ngResource', ['ng']).
           $http({
             method: action.method,
             url: route.url(extend({}, extractParams(data), action.params || {}, params)),
-            data: data
+            data: data,
+            headers: extend({}, action.headers || {})
           }).then(function(response) {
               var data = response.data;
 

test/ngResource/resourceSpec.js

@@ -14,7 +14,14 @@ describe("resource", function() {
       },
       patch: {
         method: 'PATCH'
+      },
+      conditionalPut: {
+        method: 'PUT',
+        headers: {
+          'If-None-Match': '*'
+        }
       }
+
     });
     callback = jasmine.createSpy();
   }));
@@ -146,6 +153,15 @@ describe("resource", function() {
   });
 
 
+  it('should send correct headers', function() {
+    $httpBackend.expectPUT('/CreditCard/123', undefined, function(headers) {
+       return headers['If-None-Match'] == "*";
+    }).respond({id:123});
+
+    CreditCard.conditionalPut({id: {key:123}});
+  });
+
+
   it("should read partial resource", function() {
     $httpBackend.expect('GET', '/CreditCard').respond([{id:{key:123}}]);
     var ccs = CreditCard.query();