title: AngularJS 1.2.0 $resource PUT/POST/DELETE do not send whole object
body: <p>I'm using angularjs 1.2.0 with $resource. I would like to have some PUT/POST instance actions that doesn't send the whole object to the server but only some fields and in some cases totally no data.</p>
  
  <p>Is it possible? I searched everywhere but couldn't find anything</p>
  
  <p><strong>UPDATE:</strong></p>
  
  <p>It also happens with DELETE requests:</p>
  
  <p>Given this code:</p>
  
  <pre><code>group.$deleteChatMessage({messageId: message.id}, function(){
      var i = _.indexOf(group.chat, message);
      if(i !== -1) group.chat.splice(i, 1);
  });
  </code></pre>
  
  <p>The request is this:</p>
  
  <p><img src="https://i.stack.imgur.com/pCmAF.png" alt="enter image description here"></p>
  
  <p>See how the whole model is sent (under "Request Payload").</p>
  
  <p>This is the resource:</p>
  
  <pre><code>    var Group = $resource(API_URL + '/api/v1/groups/:gid',
        {gid:'@_id', messageId: '@_messageId'},
        {
          deleteChatMessage: {method: "DELETE", url: API_URL + '/api/v1/groups/:gid/chat/:messageId'},
        });
  </code></pre>