Blazor Server App - Problem with accessing request scope in DelegatingHandler · Issue #57481 · dotnet/aspnetcore (original) (raw)

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I have a problem with getting request scope in blazor server app.

I use HttpClientFactory to communitace with one of my services. I wanted to inject dynamic header into each request.
To do so I created custom DelegatingHandler.
Because HttpClient handlers are created in a separate scope (https://andrewlock.net/understanding-scopes-with-ihttpclientfactory-message-handlers/) I took the approach with injecting IHttpContextAccessor.

Here is draft of the handler:

public class MyHeaderHandler : DelegatingHandler
{
    private readonly IHttpContextAccessor _httpContextAccessor;

    public MyHeaderHandler(IHttpContextAccessor httpContextAccessor)
    {
        _httpContextAccessor = httpContextAccessor;
    }

    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var prov = _httpContextAccessor?.HttpContext?.RequestServices.GetService(typeof(IMyProvider)) as IMyProvider;

        ...
    }
}

IMyProvider (registered as scoped service in DI) instance has some data set during request processing. I need to access that data.

The problem is that the instance I get from IHttpContextAccessor from MyHeaderHandler is different from the instance I get in blazor components or other services used there directly (not via DelegatingHandler).

I tried to set SuppressHandlerScope option to true, but no luck:

serviceCollection.Configure<HttpClientFactoryOptions>(builder.Name, options =>
        {
            options.SuppressHandlerScope = true;
        });

AFAIK this approach works in WebApi projects and the problem is with Blazor apps.
To me it looks like a BUG.
If this method of getting request scope is not correct, I would be more than happy to get some advice here.

Expected Behavior

IHttpContextAccessor.HttpContext.RequestServices gives access to request scope.

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

8.0.304

Anything else?

No response