ASP.Net core- getting routetemplate value from middleware - asp.net-core

Question

I have a middleware that is called for every request to my APIs. I want to log the route template along with the duration of the request from this middleware. How to get route template in my middleware code? Route template is something like "/products/{productId}".

Answer 1

Here is how I got it working. I get the route template inside my filter OnActionExecuting method and add it to HttpContext. Later I access this from HttpContext inside my middleware, since I can access HttpContext inside the middleware.
public class LogActionFilter : IActionFilter
{
public LogActionFilter()
{
}
public void OnActionExecuted(ActionExecutedContext context)
{
}
public void OnActionExecuting(ActionExecutingContext context)
{
context.HttpContext.Items.Add("RouteTemplate", context.ActionDescriptor.AttributeRouteInfo.Template);
}
}

Answer 2

It's not easy to get the route data from a custom middleware because it is created by MVC middleware which generally happens to be the last middleware to be executed in the ASP.NET Core pipeline.
If you want to log the request and response in your middleware as below,
public async Task Invoke(HttpContext context)
{
var requestBodyStream = new MemoryStream();
var originalRequestBody = context.Request.Body;
await context.Request.Body.CopyToAsync(requestBodyStream);
requestBodyStream.Seek(0, SeekOrigin.Begin);
var url = UriHelper.GetDisplayUrl(context.Request);
var requestBodyText = new StreamReader(requestBodyStream).ReadToEnd();
_logger.Log(LogLevel.Information, 1, $"REQUEST METHOD: {context.Request.Method}, REQUEST BODY: {requestBodyText}, REQUEST URL: {url}", null, _defaultFormatter);
requestBodyStream.Seek(0, SeekOrigin.Begin);
context.Request.Body = requestBodyStream;
await next(context);
var bodyStream = context.Response.Body;
var responseBodyStream = new MemoryStream();
context.Response.Body = responseBodyStream;
await _next(context);
responseBodyStream.Seek(0, SeekOrigin.Begin);
var responseBody = new StreamReader(responseBodyStream).ReadToEnd();
_logger.Log(LogLevel.Information, 1, $"RESPONSE LOG: {responseBody}", null, _defaultFormatter);
responseBodyStream.Seek(0, SeekOrigin.Begin);
await responseBodyStream.CopyToAsync(bodyStream);
}
However, if you are really interested in route data, there is very nice SO answer to implement a get routes miidleware here
Other alternative approach would be to use Action Filtersfor request/response logging.

Answer 3

You can actually achieve this quite easily with ASP.NET Core 3.0+ by getting the ControllerActionDescriptor from the context in a middleware:
public async Task InvokeAsync(HttpContext context, RequestDelegate next)
{
Endpoint endpointBeingHit = context.Features.Get<IEndpointFeature>()?.Endpoint;
ControllerActionDescriptor actionDescriptor = endpointBeingHit?.Metadata?.GetMetadata<ControllerActionDescriptor>();
this.logger.LogInformation(
"Matched route template '{template}'",
actionDescriptor?.AttributeRouteInfo.Template);
await next();
}

Answer 4

it's work for me:
(context.Features.Get<IEndpointFeature>()?.Endpoint as RouteEndpoint)?.RoutePattern.RawText;
Where context is HttpContext