[Blazor] Custom CircuitHandler latency breaks WS connection on navigation

[garrettlondon1]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

namespace Microsoft.AspNetCore.Components.Server.Circuits;


public class BlazorCircuitHandler() : CircuitHandler
{
    public override async Task OnCircuitOpenedAsync(Circuit circuit, CancellationToken cancellationToken)
    {
        await Task.Delay(2000);
        await base.OnCircuitOpenedAsync(circuit, cancellationToken);
    }

    public override async Task OnCircuitClosedAsync(Circuit circuit, CancellationToken cancellationToken)
    {
        await base.OnCircuitClosedAsync(circuit, cancellationToken);
    }
}

A lot of people use custom Blazor Server CircuitHandler implementations for initializing user state, connecting to SignalR Hubs, etc.

As seen in the video below, if you load a page with an InteractiveServer component, and navigate away before the circuit is opened, the whole circuit breaks. Thus, the whole app breaks.

Expected Behavior

This would be solved with #55127, because enhanced navigation would reopen the broken connection.

Steps To Reproduce

Add custom circuit handler implementation to services

Screen.Recording.2024-12-30.at.2.03.27.AM.mov

Exceptions (if any)

No response

.NET Version

9.0.100

Anything else?

No response

[javiercn]

@garrettlondon1 thanks for contacting us.

Can you turn on detailedErrors so that we can see what's going on?

[garrettlondon1]

Hi @javiercn , is that detailedErrors on the Server side?

builder.Services.AddSignalR(o => {
        o.EnableDetailedErrors = true;
    })

That doesn't send anything additional to JS console or log to server side.. is there a way to customize the Blazor.start() in order to log JS client side detailed errors not returned by the server?

This is not an error happening on the server, I believe its fully client side issue with blazor.web.js. Is there a client side callback to intercept any of these socket errors in blazor.web.js?