SignalR What?

Barend Bootha

http://drop.barendb.com/talks/signalr/index.html
Demo Code
QRCode

Who Am I?

Barend Bootha

Lead Developer at iTICKET

www.iticket.co.nz

@barendb

Pronounced

Barend: /Bar'rin'd/

For all you kiwi's :)

Agenda

What is SignalR?

Use Cases

Code Demo

Understanding the ARRR

SignalR on Azure

Questions

Links

Web
+

Full-Duplex communication over HTTP

SignalR is...

Cross client wrapper for WebSockets, abstracts transport

- JavaScript
- WP7
- iOS
- Redis
- Azure

Fallback transport for lesser browsers

- WebSockets
- Long Polling fallback

Dashboards: Stock Tickers / Analytics / Live Scores / Auctions

Monitoring: Gather Analytics / Insights

Real time notifications [Push like]

Collabrative apps

OMG Chat! ...no it's lame!

I've seen this all before...

Forever Frame

Server tells client response is chucked

Client keeps the connection open till the client closes it

Server pushes data to client followed by \0

Consumes server threads

Periodic Polling

Server is polled from time to time via AJAX

Delay in communication due to polling interval

Wastes bandwidth & latency

Consumes server threads

Long Polling

Poll but do not respond until there is data

Poll again after data is recieved or connection times out

Consumes server threads and resources

Demo - ShootR

http://shootr.signalr.net/

Demo

Getting SignalR

PM> Install-Package Microsoft.AspNet.SignalR -pre

Code deep dive

Persistant connection(s)

Can communicate with 1..N clients
Is an IHttpHandler
Requires a route to be defined
Limited to sending messages
You define the protocol

public class MyEndPoint : PersistentConnection 
{
    // blah code
}

using System;
using System.Web.Routing;
using Microsoft.AspNet.SignalR;

namespace WebApplication1
{
    public class Global : System.Web.HttpApplication
    {
        void Application_Start(object sender, EventArgs e)
        {
            RouteTable.Routes.MapConnection<MyEndPoint>("echo", 
                "echo/{*operation}");
        }
    }
}

PersistentConnection API

Task OnConnectedAsync(IRequest request, string connectionId)

Task OnReconnectedAsync(IRequest request, IEnumerable groups, 
					string connectionId)

IEnumerable OnRejoiningGroups(IRequest request, IEnumerable groups, 
					string connectionId)

Task OnReceivedAsync(IRequest request, string connectionId, string data)

Task OnDisconnectAsync(IRequest request, string connectionId)

Code deep dive

Hub(s)

Abstraction over PersistantConnection
Route automatically mapped (/signalr/hubs)
Can send messages and call methods
SignalR defines the protocol
Target all / group / individual client(s)

public class MyHub : Hub
{
    // blah code
}

public class Global : System.Web.HttpApplication
{
    protected void Application_Start(object sender, EventArgs e)
    {
        // Register the default hubs route: ~/signalr/hubs
        RouteTable.Routes.MapHubs();
    }
}

C#

public class MyHub : Hub
{
     public void Send(string message)
     {
         Clients.All.myMethodOnClient(message);
     }
}

JS

<script src="Scripts/jquery-1.6.2.min.js" type="text/javascript"></script>
<script src="Scripts/jquery.signalR.min.js" type="text/javascript"></script>
<script src="signalr/hubs" type="text/javascript"></script>

var myHub = $.connection.myHub;
					
myHub.server.myMethodOnServer('Hello World from SignalR');

Windows Azure

PM> Install-Package Microsoft.AspNet.SignalR.ServiceBus -Pre

public class MvcApplication : System.Web.HttpApplication
{
    private string topicPathPrefix = "your_topic";

    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();

        WebApiConfig.Register(GlobalConfiguration.Configuration);
        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);

        GlobalHost.DependencyResolver.UseServiceBus(
                        ConfigurationManager.AppSettings["Microsoft.ServiceBus.ConnectionString"], partitionCount: 5, nodeCount: getRoleInstanceCount(), nodeId: getRoleInstanceNumber(), topicPrefix: topicPathPrefix);
    }

    private int getRoleInstanceCount()
    {
        return RoleEnvironment.CurrentRoleInstance.Role.Instances.Count;
    }
    private int getRoleInstanceNumber()
    {
            
        var roleInstanceId = RoleEnvironment.CurrentRoleInstance.Id;
        var li1 = roleInstanceId.LastIndexOf(".");
        var li2 = roleInstanceId.LastIndexOf("_");
        var roleInstanceNo = roleInstanceId.Substring(Math.Max(li1, li2) + 1);
        return Int32.Parse(roleInstanceNo);
    }

}