AngularJS service to send auth token with $resource requests

angularjs_resource_tokenhandler.js

.factory('TokenHandler', function() {
  var tokenHandler = {};
  var token = "none";

  tokenHandler.set = function( newToken ) {
    token = newToken;
  };

  tokenHandler.get = function() {
    return token;
  };

  // wrap given actions of a resource to send auth token with every
  // request
  tokenHandler.wrapActions = function( resource, actions ) {
    // copy original resource
    var wrappedResource = resource;
    for (var i=0; i < actions.length; i++) {
      tokenWrapper( wrappedResource, actions[i] );
    };
    // return modified copy of resource
    return wrappedResource;
  };

  // wraps resource action to send request with auth token
  var tokenWrapper = function( resource, action ) {
    // copy original action
    resource['_' + action]  = resource[action];
    // create new action wrapping the original and sending token
    resource[action] = function( data, success, error){
      return resource['_' + action](
        angular.extend({}, data || {}, {access_token: tokenHandler.get()}),
        success,
        error
      );
    };
  };

  return tokenHandler;
});

How would I modify this to add custom headers?

I had lost my 'params' while using this way.