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Connect groups with Redis or NATS

You can connect groups between multiple server instances using Redis or NATS. This is equivalent to the backplane of SignalR.

By using this mechanism, you can send messages to clients belonging to a specific group regardless of the server instance. This allows you to build an architecture that can scale out the server.

Connect groups with Redis​

To use Redis, install the MagicOnion.Server.Redis package.

dotnet add package MagicOnion.Server.Redis

Next, set up to use Redis by using the UseRedisGroup method on the builder returned by AddMagicOnion.

builder.Services.AddMagicOnion()
    .UseRedisGroup(options =>
    {
        //options.ConnectionString = "localhost:6379";
        //options.ConnectionMultiplexer = ConnectionMultiplexer.Connect("localhost:6379");
    });

The UseRedisGroup method has an optional argument to specify whether to use the default group provider. Specify true if you want to use the default group provider. If not specified or false is specified, you need to specify the group provider for each StreamingHub using the [GroupConfiguration] attribute.

[GroupConfiguration(typeof(RedisGroupProvider))]
public class MyStreamingHub : StreamingHubBase<IMyStreamingHub, IMyStreamingHubReceiver>, IMyStreamingHub
{
    // ...
}

Connect groups with NATS (Preview)​

NATS support is currently in preview and is provided as a package for Multicaster. To use NATS, install the Multicaster.Distributed.Nats package.

dotnet add package Multicaster.Distributed.Nats

Next, register NatsGroupOptions with the service.

builder.Services.AddSingleton<NatsGroupOptions>(new NatsGroupOptions() { Url = "nats://localhost:4222" });

Specify the group provider to use NATS in StreamingHub by using the [GroupConfiguration] attribute.

[GroupConfiguration(typeof(NatsGroupProvider))]
public class MyStreamingHub : StreamingHubBase<IMyStreamingHub, IMyStreamingHubReceiver>, IMyStreamingHub
{
    // ...
}

If you want to use NATS as the default group provider, replace IMulticastGroupProvider as follows.

builder.Services.RemoveAll<IMulticastGroupProvider>();
builder.Services.AddSingleton<IMulticastGroupProvider, NatsGroupProvider>();

Limitations​

  • Client results are not supported
  • Count, CountAsync methods are not supported