C# Tridion Event System code for sending messages to the MessageCenter using the Signalr4Tridion GUI Extension

PublishNotificationHandler.cs

using System;
using Microsoft.AspNet.SignalR.Client;
using Tridion.ContentManager;
using Tridion.ContentManager.ContentManagement;
using Tridion.ContentManager.Extensibility;
using Tridion.ContentManager.Extensibility.Events;
using Tridion.ContentManager.Publishing;

namespace EventSystemSignalr
{
    [TcmExtension("Publish Transaction Notification Event Handler")]
    public class PublishNotificationHandler : TcmExtension
    {
        public PublishNotificationHandler()
        {
            EventSystem.Subscribe<PublishTransaction, SaveEventArgs>(TransactionSaved, EventPhases.TransactionCommitted);
            EventSystem.Subscribe<Component, SaveEventArgs>(ComponentSaved, EventPhases.TransactionCommitted);
        }

        public void TransactionSaved(PublishTransaction transaction, SaveEventArgs args, EventPhases phases)
        {
            string message = GetMessage(transaction);

            if (!String.IsNullOrEmpty(message))
            {
                var connection = new Connection("http://localhost:8123/channel");
                connection.Start().Wait();
                int userId = GetUserId(transaction);
                connection.Send("join " + userId);
                connection.Send(userId + ":" + message);
                connection.Stop();
            }
        }

        public void ComponentSaved(Component component, SaveEventArgs args, EventPhases phases)
        {
            var connection = new Connection("http://localhost:8123/channel");
            connection.Start().Wait();
            connection.Send("Component " + component.Title + ", hello from SignalR ");
            connection.Stop();       
        }

        private int GetUserId(PublishTransaction tridionObject)
        {
            TcmUri userUri = tridionObject.Creator.Id;
            return userUri.ItemId; 
        }

        private string GetMessage(PublishTransaction transaction)
        {
            string message = "";
            if (transaction.State == PublishTransactionState.Success)
            {
                if (transaction.Items.Count == 1)
                {
                    message = "Publishing " + transaction.Items[0].Title + " completed.";
                }
            }
            else if (transaction.State == PublishTransactionState.Failed)
            {
                if (transaction.Items.Count == 1)
                {
                    message = "Publishing " + transaction.Items[0].Title + " failed.";
                }
            }

            return message;
        }
    }
}