ASP.NET Core performance middleware doesn't handle Attribute routing

[kanadaj]

With the current middleware implementation, attribute routing (eg [Route("/route/{param}")] ) is still handled as paths. There are 2 possible ways to work around this:

1. On platforms where available, use httpContext.GetRouteData() (probably .NET Core 3 and newer), which extracts httpContext.Request.RouteValues if it's available.
2. If the above is insufficient, move transaction name retrieval to after the middleware pipeline:

var transaction = hub.CreateTransaction(
    context.Request.Path, // Placeholder
    "http.server"
);

try
{
    await _next(context).ConfigureAwait(false);
}
finally
{
    transaction.Name = context.GetTransactionName();
    transaction.Finish(
        GetSpanStatusFromCode(context.Response.StatusCode)
    );
}

which will allow any logic that modifies routing to be applied before the transaction is sent.

[kanadaj]

cc @Tyrrrz

[Tyrrrz]

Afaik httpContext.GetRouteData() returns httpContext.Features.Get<IRoutingFeature?>()?.RouteData under the hood.

sentry-dotnet/src/Sentry.AspNetCore/Extensions/HttpContextExtensions.cs

Lines 12 to 51 in 72c6aa6

	public static string? TryGetRouteTemplate(this HttpContext context)
	{
	#if !NETSTANDARD2_0
	// Requires .UseRouting()/.UseEndpoints()
	var endpoint = context.Features.Get<IEndpointFeature?>()?.Endpoint as RouteEndpoint;
	var routePattern = endpoint?.RoutePattern.RawText;
	if (!string.IsNullOrWhiteSpace(routePattern))
	{
	return routePattern;
	}
	#endif
	// Requires legacy .UseMvc()
	var routeData = context.Features.Get<IRoutingFeature?>()?.RouteData;
	var controller = routeData?.Values["controller"]?.ToString();
	var action = routeData?.Values["action"]?.ToString();
	var area = routeData?.Values["area"]?.ToString();
	if (!string.IsNullOrWhiteSpace(action))
	{
	return !string.IsNullOrWhiteSpace(area)
	? $"{area}.{controller}.{action}"
	: $"{controller}.{action}";
	}
	// If the handler doesn't use routing (i.e. it checks `context.Request.Path` directly),
	// then there is no way for us to extract anything that resembles a route template.
	return null;
	}
	public static string GetTransactionName(this HttpContext context)
	{
	// Try to get the route template or fallback to the request path
	var method = context.Request.Method.ToUpperInvariant();
	var route = context.TryGetRouteTemplate() ?? context.Request.Path;
	return $"{method} {route}";
	}

I'm guessing the logic short-circuits when it finds the route name on the endpoint feature and doesn't get to the routing feature. I wonder if switching them around would fix the issue.

[kanadaj]

Update on this one, this seems to only happen when a route 404s.

Also, GetRouteData() actually does more:

https://github.com/dotnet/aspnetcore/blob/c925f99cddac0df90ed0bc4a07ecda6b054a0b02/src/Http/Routing.Abstractions/src/RoutingHttpContextExtensions.cs#L30