ASP.NET SignalR

SignalR allows developers to create real-time ASP.NET web applications, where the server broadcasts the updates to all registered clients as soon as an update is triggered. This cuts down on the delay caused by the wait for client requests for updates.

A simple example of SignalR implementation is online chatroom. Multiple clients are connected to multiple web servers in a farm. These clients can be sending messages to each other, where the message content is displayed as soon as it is sent to the receiving client. This eliminates the need to refresh the webpage every time to request for new messages, as the server broadcasts the message to all clients as soon as the client state is updated.

Note

Please refer to the Chatroom sample application provided for SignalR located at %NCHOME%\samples\dotnet\SignalRChat.

NCache offers support for SignalR by providing extension to the SignalR provider. All concerned web servers for the application are registered against the provider. Meanwhile, the clients are connected to their respective web servers. In NCache, as soon as a client registers itself against the webserver, two key features of NCache come into play:

  1. Custom Events: The provider fires an event as soon as a client performs an operation. This event triggers all web servers to immediately update their clients according to the latest state, thereby cutting down on the waiting duration of a client to check on updates.

  2. CacheItem.Version: As soon as a client is registered against a web server, an item is added to NCache with user specified event key. Every time the client will perform an operation, the version of the cache item is updated, triggering an event registered against the provider. This allows for instant replication of the client state over all clients, which causes the real-time effect.

In This Section

Using NCache Extension for SignalR
Explains how NCache's extended method can be used to utilize SignalR in your ASP.NET applications.