Extension for ASP.NET SignalR Backplane

NCache provides an extension for the ASP.NET SignalR Backplane by extending the IDependencyResolver interface. Using theUseNCache method, you can scale out real-time applications by registering NCache as the message bus backplane. This integration requires only the cacheName and eventKey to synchronize message broadcasting across distributed web farms.

The UseNCache method takes in the following parameters:

Parameters Type Description
cacheName String Name of the cache in NCache that will store the respective item for the client to trace updates via itemVersion.
eventKey String Unique user-specified key attribute for the item added to NCache on client registration. The event key is specific to the application. Each client of the application will use the same event key while calling NCache's extension method.
configuration NCacheScaleoutConfiguration An object of NCacheScaleoutConfiguration which extends the ScaleoutConfiguration class and takes in cacheName, eventKey, userid, and password as members.

Prerequisites

  • Install the following NuGet packages in your application based on your NCache edition:
  • To utilize the extension, include the following namespaces in your application in Startup.cs:
  • The cache must be running.
  • Make sure to use the version 2.4.0 and onwards of ASP.NET SignalR.
  • For API details, refer to: UseNCache.
  • Make sure that the data added is serializable.
  • To ensure the operation is fail safe, it is recommended to handle any potential exceptions within your application, as explained in Handling Failures.
  • To handle any unseen exceptions, refer to the Troubleshooting section.

Modify Web.config

Add the configSections tag in <configuration> as follows:

<configuration>
  <configSections>
    <section name="ConnectionOptions"
    type="Alachisoft.NCache.AspNet.SignalR.SignalRConnectionOptions"/>
 </configSections>
</configuration>

Add the ConnectionOptions section in <configuration> to set different properties to be used at the time of client connection with the cache. For a detailed description of parameters provided in the ConnectionOptions object, refer to CacheConnectionOptions Properties.

<configuration>
  <ConnectionOptions ClientBindIp="" AppName="DemoAppName" EnableClientLogs="false" LogLevel="info">
    <Server name="20.200.21.39" port="9800"/>
    <UserCredentials userID="john doe" password="1234" />
 </ConnectionOptions>
</configuration>

Add appSettings section specifying cacheName and eventKey in <configuration> as follows:

<appSettings>
  <add key="cache" value="demoCache" />
  <add key="eventKey" value="chatApplication" />
</appSettings>

Register Clients to use NCache

Register an instance of the UseNCache method in Startup.cs of your application in either of the following overloads:

Overload 1:

public static IDependencyResolver UseNCache(this IDependencyResolver resolver, string cacheName, string eventKey, string userID = null, string password = null)

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        string cache, eventKey;
        cache = ConfigurationManager.AppSettings["cache"];
        eventKey = ConfigurationManager.AppSettings["eventKey"];
        GlobalHost.DependencyResolver.UseNCache(cache, eventKey);

        //using NCache SignalR
        app.MapSignalR();
    }
}

Overload 2:

public static IDependencyResolver UseNCache(this IDependencyResolver resolver, NCacheScaleoutConfiguration configuration)

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        string cache, eventKey, userId ="", password="";
        cache = ConfigurationManager.AppSettings["cache"];
        eventKey = ConfigurationManager.AppSettings["eventKey"];
        var options = (CacheConnectionOptions)ConfigurationManager.GetSection("ConnectionOptions");
        if (options!= null && options.UserCredentials != null)
        {
            userId = options.UserCredentials.UserID;
            password = options.UserCredentials.Password;
        }

        var configuration = new NCacheScaleoutConfiguration(cache, eventKey, userId, password);
        GlobalHost.DependencyResolver.UseNCache(configuration); //using NCache SignalR
        app.MapSignalR();
    }
}

Additional Resources

NCache provides sample application for SignalR on GitHub.

See Also

.NET: Alachisoft.NCache.AspNet.SignalR namespace.