NCache Extension for ASP.NET SignalR Backplane

NCache extends the IDependencyResolver DependencyResolver() method with its UseNCache() method which requires just the cache name and event key for the item added. This acts as the registration point for the clients against the SignalR implementation.

UseNCache() takes in the following parameters:

Parameters	Type	Description
cacheName	string	Name of the cache in NCache which 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. 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

• .NET/.NET Core

• Install the following NuGet packages in your application based on your NCache Version:
  • Enterprise: AspNet.SignalR.NCache
  • Professional: AspNet.SignalR.NCache.Professional
  • OpenSource: AspNet.SignalR.NCache.OpenSource
• To utilize the extension, include the following namespaces in your application in Startup.cs:
  • Alachisoft.NCache.AspNet.SignalR
  • Microsoft.AspNet.SignalR
• The cache must be running.
• Make sure to use the version >= 2.4.0 of ASP.NET SignalR.
• For API details, refer to: UseNCache.
• Make sure that the data being 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 ConnectionOptions section in <configSections> as follows.

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

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

<configuration>
  <ConnectionOptions ClientBindIp="" AppName="DemoAppName" EnableClientLogs="false" LogLevel="info">
    <Server name="20.200.21.31" port="9800"/>
    <UserCredentials userID="john doe" password="1234" />
 </ConnectionOptions>
<configuration>

Add appSettings section specifying cacheName and eventKey in <configuration> as folows.

<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.csof 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

ASP.​NET Session State Provider for NCache
View State Caching
Multi-Region ASP.NET Session State Provider for NCache