This document introduces SignalR, an open source library for ASP.NET that enables real-time web functionality. SignalR allows for persistent connections and events between client and server. It abstracts away the transport layer so applications can focus on two-way communication instead of polling. Live demos show how clients can call servers and vice versa without polling. SignalR works natively in .NET and supports platforms like iOS and Mono. While other technologies solve this problem, SignalR offers simplicity, ease of use within .NET, and support for WebSockets.

1. Local Touch – Global Reach
Intro to SignalR + Awesome Mobile Possibilities !
Samidip Basu
Solutions Lead | MSFT Mobility
Email: Samidip.Basu@us.sogeti.com
Twitter: @samidip
Info: http://samidipbasu.info
Blog: http://samidipbasu.com
Sogeti USA
8425 Pulsar Place, Suite 300 | Columbus, OH 43240.
www.us.sogeti.com
www.us.sogeti.com

2. Central Ohio Windows Phone User Group
http://cowpug.org
http://meetup.com/cowpug
@cowpug
3rd Monday @ TechColumbus

3. Why do we need real-time?
New email
Twitter/Facebook updates
Stock Ticker/Live Auctions
Game Scores
Real-time Notifications
Turn-by-Turn Games
Collaboration
Progress Bars
And obviously, Chat

4. Existing Technologies
HTTP – purely Request/Response protocol
Internet – stateless; servers don’t call your app back
Consumption model .. But we’ve learnt tricks
Periodic/Ajax Polling – not real-time, bandwidth misuse
Image courtesy

5. Existing Technologies ..
Contd.
Use plugins like SL/Flash – to access sockets
Native Web Sockets help – but low level & support flaky
Long Polling – server does not respond unless X happens,
client polls after data receive or time-out
Image courtesy @maartenballiauw

6. Enter SignalR
An async, persistent connection/signalling library for .NET ... aids in building
real time, multi-user connected applications.
Persistent client-server connection over best transport .. Abstracts away the
transport layer.
From ASP.NET team-members (Damian Edwards & David Fowler) ..
Not officially MSFT product, but OSS Booyah 
https://github.com/SignalR/SignalR
http://jabbr.net/#/rooms/signal
SignalR is broken up into a few packages on NuGet:
SignalR - Package for SignalR.Server and SignalR.Js
SignalR.Server - Server components needed for SignalR endpoints
SignalR.Js - Javascript client for SignalR
SignalR.Client - .NET client for SignalR
SignalR.WP7 & SignalR.Silverlight – For the cool folks 
SignalR.WebSockets - WebSocket Transport for SignalR

7. Live Demos
Whoa .. What happened here?
Client calls server; Server calls client; seamlessly
No polling, at least in our code
Server maintains Clients .. Broadcast to all, group or individual clients
Low level – PersistentConnection; more control
Abstraction – Hub; easier to use

8. Where does this fit?
Other technologies have solved this problem
Socket.IO is a client-side Jscript library that talks to node.js
Nowjs supports namespace sync between client-server
Primary SignalR advantages
→ Simplicity & ease of use
→ Works natively in .NET
→ Works out of browser
→ Supports Web Sockets through a NuGet package
[ASP.NET 4.5/IIS 8 on Win8 only]
WebSocket is a web technology providing for multiplexing bi-directional, full-duplex
communications channels over a single TCP connection. Still being standardized.
→ Works on other platforms

9. SignalR Client for iOS
http://dyknow.github.com/SignalR-ObjC/

10. SignalR Client for Mono
http://blog.rthand.com/post/2012/03/14/SignalR-client-on-Mono-for-Android.aspx

11. Local Touch – Global Reach
Questions?
Thank you !!
@samidip
www.us.sogeti.com