Signal R

Signal R

What is signal R? Where to use?

Signal r is a new developer’s API provided for ASP.NET web applications, used to add "real time" web functionality to ASP.NET applications. "Real Time" web functionality is the ability to have server code to push contents to connected clients.

SignalR supports "server push" or "broadcasting" functionality. It handles connection management automatically. In classic HTTP connections for client-server communication connection is re-established for each request, but SignalR provides persistent connection between the client and the server.SignalR is an open-source API, and is accessible through GitHub.

Where to use:

·         Chat room applications

·         Real-time monitoring applications

·         Job progress updates

·         Gaming applications

What technologies does SignalR use to transfer data?

·         Using WebSockets if it is available

·         Otherwise, using other technologies, e.g. long polling,Server Sent Events ,Forever Frames

What kind of data does SignalR support to transfer?

• Non-compressed JSON text or plain textIf you want to transfer compressed JSON or BSON or your binary data, you have to encodeusing Base64) or to
• Implement IJsonSerializer by your own logic on the server side and implement the same logic on the client side. Note that TextReader and TextWriter are used inside SignalR. That means you have to convert your data to text before transferring anyway.

API Details:

SignalR provides two models for communication:

1.    Persistent Connections

The Persistent Connection API gives developer direct access to the low level communication protocol that SignalR exposes. This API uses the format of the actual message sent that needs to be specified and if the developer prefers to work with messaging and dispatching model rather than a remote invocation.

2.    Hubs:

It's a High Level API written over PersistentConnection. This API allows the client and server to call methods on each other directly. Hubs also allow you to pass strongly typed parameters to methods, enabling model binding.

Figure: chat application process

Web Sockets:

They allow a long-held single TCP socket connection to be established between the client and server which allows for bi-directional, full duplex, messages to be instantly distributed with little overhead resulting in a very low latency(no delay) connection.

Both the WebSocket API and the WebSocket protocol are standardised which means the web now has an agreed standard for realtime communication between Internet clients and servers.

References:

http://msdn.microsoft.com/en-us/library/system.web.routing.routetable(v=vs.110).aspx?cs-save-lang=1&cs-lang=csharp#code-snippet-2

http://www.codeproject.com/Articles/637762/ASP-NET-SignalR-Basis-Step-by-Step-Part

http://www.codeproject.com/Articles/524066/SignalR-Simple-Chat-Application-in-Csharp

http://www.codeproject.com/Tips/590660/Introduction-to-SignalR

http://www.codeproject.com/Articles/633378/ASP-NET-SignalR-Basis-Step-by-Step-Part

http://ruwandotnet.wordpress.com/2012/03/17/74/