Pusher private channel authorization with Parse

//On client (browser)

Pusher.authorizers.parse = function (socketId, callback) {
var pusherData = {
socketid: socketId,
channelname: this.channel.name
};
Parse.Cloud.run('authorizePusherChannel', pusherData, {
success: function (result) {
callback(false, JSON.parse(result));
},
error: function (error) {
callback(true, error);
}
});
};

//On Parse Cloud Code
Parse.Cloud.define('authorizePusherChannel', function (request, response) {
if (!request.user) { response.error('User should be autenticated.'); }
var pusherAppKey = 'your-pusher-app-key';
var pusherAppSecret = 'your-pusher-app-secret';
var stringToSign = request.params.socketid + ':' + request.params.channelname;
var authToken = pusherAppKey + ':' + crypto.createHmac('sha256', pusherAppSecret).update(stringToSign).digest('hex');
response.success(JSON.stringify({auth:authToken}));
});