Merge pull request #12 from Mathavana/develop

Develop - Global Error Handle

Author: MathavanN

README.md

@@ -17,11 +17,11 @@ We will try to create an API application using asp.net core.
 - Models, Enums, Context, Repositories moved to Supermarket.Core project
 - xUnit Test Project added
 - CircleCi
-- Standard response for error (400,404) results (Similar to ApiController model validation result)
+- Standard response for error (400,404, 500) results (Similar to ApiController model validation result)
+- Global Error Handling
 
 ### Next ToDo List:
 - Role Based Authentication/Authorization
-- Global Error Handling
 - Dockerization
 - More test cases needed
 - Proper model implementation

Supermarket/ApiResponse/BadRequestResponse.cs

@@ -8,10 +8,12 @@ namespace Supermarket.ApiResponse
     public class BadRequestResponse : ValidationProblemDetails
     {
         public Guid TraceId { get; set; }
+
         public BadRequestResponse(string error) : base(new Dictionary<string, string[]> { { "error", new[] { error } } })
         {
             TraceId = Guid.NewGuid();
             Title = HttpStatusCode.BadRequest.ToString();
+            Status = (int)HttpStatusCode.BadRequest;
         }
     }
 }

Supermarket/ApiResponse/InternalServerErrorResponse.cs

@@ -0,0 +1,19 @@
+using Microsoft.AspNetCore.Mvc;
+using System;
+using System.Collections.Generic;
+using System.Net;
+
+namespace Supermarket.ApiResponse
+{
+    public class InternalServerErrorResponse : ValidationProblemDetails
+    {
+        public Guid TraceId { get; set; }
+
+        public InternalServerErrorResponse(string error) : base(new Dictionary<string, string[]> { { "error", new[] { error } } })
+        {
+            TraceId = Guid.NewGuid();
+            Title = HttpStatusCode.InternalServerError.ToString();
+            Status = (int)HttpStatusCode.InternalServerError;
+        }
+    }
+}

Supermarket/ApiResponse/NotFoundResponse.cs

@@ -8,10 +8,24 @@ namespace Supermarket.ApiResponse
     public class NotFoundResponse : ValidationProblemDetails
     {
         public Guid TraceId { get; set; }
+
         public NotFoundResponse(string error) : base(new Dictionary<string, string[]> { { "error", new[] { error } } })
         {
             TraceId = Guid.NewGuid();
             Title = HttpStatusCode.NotFound.ToString();
+            Status = (int)HttpStatusCode.NotFound;
         }
+
+        ////In feature, to log the not found response
+        //public NotFoundResponse(string error, ILogger logger) : base(new Dictionary<string, string[]> { { "error", new[] { error } } })
+        //{
+        //    TraceId = Guid.NewGuid();
+        //    Title = HttpStatusCode.NotFound.ToString();
+        //    Status = (int)HttpStatusCode.NotFound;
+        //    logger.LogInformation(JsonConvert.SerializeObject(this,
+        //                                                       Formatting.Indented,
+        //                                                       new JsonSerializerSettings { ContractResolver = new CamelCasePropertyNamesContractResolver() }
+        //                                                      ));
+        //}
     }
 }

Supermarket/Extensions/ServiceExtensions.cs

@@ -13,6 +13,7 @@
 using Supermarket.Core.Models;
 using Supermarket.Core.Repositories;
 using Supermarket.Core.Repositories.Contracts;
+using Supermarket.Middleware;
 using Supermarket.Swagger;
 using Swashbuckle.AspNetCore.Swagger;
 using System;
@@ -157,5 +158,10 @@ public static void ConfigureVersionedApiExplorer(this IServiceCollection service
                 options.SubstituteApiVersionInUrl = true;
             });
         }
+
+        public static void ConfigureCustomExceptionMiddleware(this IApplicationBuilder app)
+        {
+            app.UseMiddleware<ExceptionMiddleware>();
+        }
     }
 }

Supermarket/Middleware/ExceptionMiddleware.cs

@@ -0,0 +1,55 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Serialization;
+using Supermarket.ApiResponse;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Threading.Tasks;
+
+namespace Supermarket.Middleware
+{
+    public class ExceptionMiddleware
+    {
+        private readonly RequestDelegate _next;
+        private readonly ILogger<ExceptionMiddleware> _logger;
+
+        public ExceptionMiddleware(RequestDelegate next, ILogger<ExceptionMiddleware> logger)
+        {
+            _logger = logger;
+            _next = next;
+        }
+
+        public async Task InvokeAsync(HttpContext httpContext)
+        {
+            try
+            {
+                await _next(httpContext);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError($"API Error: {ex}");
+                await HandleExceptionAsync(httpContext, ex);
+            }
+        }
+
+        private Task HandleExceptionAsync(HttpContext context, Exception exception)
+        {
+            var code = HttpStatusCode.InternalServerError; // 500 if unexpected
+
+            ////Refer https://stackoverflow.com/questions/38630076/asp-net-core-web-api-exception-handling
+
+            var result = JsonConvert.SerializeObject(
+                                                        new InternalServerErrorResponse(exception.Message),
+                                                        Formatting.Indented,
+                                                        new JsonSerializerSettings { ContractResolver = new CamelCasePropertyNamesContractResolver() }
+                                                    );
+            _logger.LogError(result);
+            context.Response.ContentType = "application/json";
+            context.Response.StatusCode = (int)code;
+            return context.Response.WriteAsync(result);
+        }
+    }
+}

Supermarket/Startup.cs

@@ -45,8 +45,9 @@ public void ConfigureServices(IServiceCollection services)
 
             services.ConfigureRepositoryWrapper();
 
-            services.AddMvc().AddJsonOptions(options =>
+            services.AddMvcCore().AddJsonOptions(options =>
             {
+                options.SerializerSettings.Formatting = Newtonsoft.Json.Formatting.Indented;
                 options.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
             }).SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
 
@@ -64,9 +65,13 @@ public void Configure(IApplicationBuilder app, IHostingEnvironment env,
             IApiVersionDescriptionProvider provider, ILoggerFactory loggerFactory)
         {
             loggerFactory.AddSerilog();
+
+            app.ConfigureCustomExceptionMiddleware();
+
             if (env.IsDevelopment())
             {
                 app.UseDeveloperExceptionPage();
+                app.UseDatabaseErrorPage();
             }
             else
             {

Supermarket/Supermarket.csproj

@@ -26,6 +26,7 @@
     <PackageReference Include="Microsoft.AspNetCore.Mvc.Versioning.ApiExplorer" Version="3.2.0" />
     <PackageReference Include="Microsoft.AspNetCore.Razor.Design" Version="2.2.0" PrivateAssets="All" />
     <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="2.2.3" />
+    <PackageReference Include="Newtonsoft.Json" Version="12.0.1" />
     <PackageReference Include="Serilog.AspNetCore" Version="2.1.1" />
     <PackageReference Include="Serilog.Settings.Configuration" Version="3.0.1" />
     <PackageReference Include="Serilog.Sinks.RollingFile" Version="3.3.0" />

Supermarket/V1/Controllers/AboutController.cs

@@ -1,7 +1,6 @@
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Logging;
-using System.Threading.Tasks;
 
 namespace Supermarket.V1.Controller
 {

Supermarket/V1/Controllers/ProductsController.cs

@@ -4,7 +4,6 @@
 using Microsoft.AspNetCore.Mvc;
 using Supermarket.Core.Models;
 using Supermarket.Core.Repositories.Contracts;
-using Supermarket.Resources;
 using Supermarket.V1.Dtos.ProductDtos;
 using System.Collections.Generic;
 using System.Threading.Tasks;