.NET Core Middleware – Getting Form Data from Request

asp.net-coreasp.net-core-middlewarec++

In a .NET Core Web Application I am using middleware (app.UseMyMiddleware) to add some logging on each request:

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler(MyMiddleware.GenericExceptionHandler);
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseMyMiddleware();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
            });
        }

        public static void UseMyMiddleware(this IApplicationBuilder app)
        {
            app.Use(async (context, next) =>
            {
                await Task.Run(() => HitDetails.StoreHitDetails(context));
                await next.Invoke();
            });
        }

        public static void StoreHitDetails(HttpContext context)
        {
            var config = (IConfiguration)context.RequestServices.GetService(typeof(IConfiguration));
            var settings = new Settings(config);
            var connectionString = config.GetConnectionString("Common");
            var features = context.Features.Get<IHttpRequestFeature>();
            var url = $"{features.Scheme}://{context.Request.Host.Value}{features.RawTarget}";

            var parameters = new
            {
                SYSTEM_CODE = settings.SystemName,
                REMOTE_HOST = context.Connection.RemoteIpAddress.ToString(),
                HTTP_REFERER = context.Request.Headers["Referer"].ToString(),
                HTTP_URL = url,
                LOCAL_ADDR = context.Connection.LocalIpAddress.ToString(),
                AUTH_USER = context.User.Identity.Name
            };

            using (IDbConnection db = new SqlConnection(connectionString))
            {
                db.Query("StoreHitDetails", parameters, commandType: CommandType.StoredProcedure);
            }
        }

This all works fine and I can grab most of what I need from the request but what I need next is the Form Data on a POST method.

context.Request.Form is an available option but when debugging I hover over it and see "The function evaluation requires all thread to run". If I try to use it the application just hangs.

What do I need to do to access Request.Form or is there an alternative property with POST data that I'm not seeing?

Best Answer

You can create a separate middleware rather than an inline one and then call the HitDetails.StoreHitDetails from there.

public class MyMiddleware
{
    private readonly RequestDelegate _next;

    public MyMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task Invoke(HttpContext context)
    {
        HitDetails.StoreHitDetails(context);

        await _next(context);
    }
}

// Extension method used to add the middleware to the HTTP request pipeline.
public static class MiddlewareExtensions
{
    public static IApplicationBuilder UseMyMiddleware(this IApplicationBuilder builder)
    {
        return builder.UseMiddleware<MyMiddleware>();
    }
}

That way you can continue using app.UseMyMiddleware(); and you don't have to run it using Task.Run as you mentioned.

Or you can just try calling HitDetails.StoreHitDetails(context) without wrapping it in Task.Run

Edited

Check if your Request has a correct content type:

if (context.Request.HasFormContentType)
{
    IFormCollection form;
    form = context.Request.Form; // sync
    // Or
    form = await context.Request.ReadFormAsync(); // async

    string param1 = form["param1"];
    string param2 = form["param2"];
 }
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