Added API demo case for ASP.NET Core 3 + with context.Request.EnableB…

…uffering(); fix (#559)

* Added api controller

* context.Request.EnableBuffering();

examples/ASP.NET Core 3/ASP.NET Core 3 - VS2019/Controllers/ApiController.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
+
+namespace ASP.NET_Core_3___VS2019.Controllers
+{
+    [Route("api/[controller]")]
+    [ApiController]
+    public class LogTestsController : ControllerBase
+    {
+        private readonly ILogger<LogTestsController> _logger;
+
+        public LogTestsController(ILogger<LogTestsController> logger)
+        {
+            _logger = logger;
+        }
+
+        [HttpPost]
+        public async Task<ActionResult> TestLog([FromBody]string request)
+        {
+            try
+            {
+                throw new ApplicationException("Test log message");
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Test error logging");
+                return StatusCode(StatusCodes.Status500InternalServerError, ex.Message);
+            }
+        }
+    }
+}

examples/ASP.NET Core 3/ASP.NET Core 3 - VS2019/Startup.cs

@@ -4,6 +4,7 @@
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.HttpsPolicy;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
@@ -41,17 +42,23 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
             }
             app.UseHttpsRedirection();
             app.UseStaticFiles();
-
             app.UseRouting();
-
             app.UseAuthorization();
 
+            // needed for  ${aspnet-request-posted-body} with an API Controller. Must be before app.UseEndpoints
+            app.Use(async (context, next) => {
+                context.Request.EnableBuffering();
+                await next();
+            });
+
             app.UseEndpoints(endpoints =>
             {
                 endpoints.MapControllerRoute(
                     name: "default",
                     pattern: "{controller=Home}/{action=Index}/{id?}");
             });
+
+
         }
     }
 }