HotChocolate/StrawberryShake Subscription Interception Demo

This is a simple chat application built to demonstrate real-time messaging using WebSocket-based GraphQL subscriptions. Additionally, it is useful for debugging custom socket connection interceptors for HotChocolate and StrawberryShake.

Components

Server-Side

The interceptor for the server-side is the ChatSocketSessionInterceptor.

Here's how it is set up on the request executor builder (in Program.cs):

builder.AddGraphQL()
      .AddTypes()
      .AddInMemorySubscriptions()
      .AddSocketSessionInterceptor<ChatSocketSessionInterceptor>();

Client-Side

The interceptor for the client-side is the ChatConnectionInterceptor.

Here is how the client is set up (in Program.cs):

builder.Services.AddPingPongGraphClient()
    .ConfigureHttpClient(client => client.BaseAddress = new Uri(builder.Configuration["GraphQLEndpoint"]!))
    .ConfigureWebSocketClient((services, client) =>
    {
        var logger = services.GetRequiredService<ILogger<Program>>();

        logger.LogInformation("Creating web socket client");

        try
        {
            logger.LogInformation("Getting Interceptor");
            // this is the important piece VVVV
            var theInterceptor = services.CreateScope().ServiceProvider.GetRequiredService<ChatConnectionInterceptor>();
            client.Uri = new Uri(builder.Configuration["GraphQLEndpoint"]!.Replace("http", "ws"));
            client.ConnectionInterceptor = theInterceptor;
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "Failed to fetch web socket connection interceptor");
            throw;
        }
    });

The important thing to note here is that the client's connection interceptor HAS to be provided from a new scope. Otherwise, the WebSocket client cannot be generated by this factory. The StrawberryShake generated client has 2 separate service collections internally and without the scope being created the service will not be returned.