manage conflict (generic way) use toast to show error (#588)

* manage conflict (generic way) use toast to show error

* fix httpservice after merge conflict, adapt to use new repository

src/PublicApi/CatalogItemEndpoints/Create.cs

@@ -3,9 +3,10 @@ using Microsoft.AspNetCore.Authentication.JwtBearer;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.eShopWeb.ApplicationCore.Entities;
+using Microsoft.eShopWeb.ApplicationCore.Exceptions;
 using Microsoft.eShopWeb.ApplicationCore.Interfaces;
+using Microsoft.eShopWeb.ApplicationCore.Specifications;
 using Swashbuckle.AspNetCore.Annotations;
-using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -38,8 +39,14 @@ namespace Microsoft.eShopWeb.PublicApi.CatalogItemEndpoints
         {
             var response = new CreateCatalogItemResponse(request.CorrelationId());
 
-            var newItem = new CatalogItem(request.CatalogTypeId, request.CatalogBrandId, request.Description, request.Name, request.Price, request.PictureUri);
+            var catalogItemNameSpecification = new CatalogItemNameSpecification(request.Name);
+            var existingCataloogItem = await _itemRepository.CountAsync(catalogItemNameSpecification, cancellationToken);
+            if (existingCataloogItem > 0)
+            {
+                throw new DuplicateException($"A catalogItem with name {request.Name} already exists");
+            }
 
+            var newItem = new CatalogItem(request.CatalogTypeId, request.CatalogBrandId, request.Description, request.Name, request.Price, request.PictureUri);
             newItem = await _itemRepository.AddAsync(newItem, cancellationToken);
 
             if (newItem.Id != 0)

src/PublicApi/MiddleWares/ExceptionMiddleware.cs

@@ -0,0 +1,46 @@
+using BlazorShared.Models;
+using Microsoft.AspNetCore.Http;
+using Microsoft.eShopWeb.ApplicationCore.Exceptions;
+using System;
+using System.Net;
+using System.Threading.Tasks;
+
+namespace Microsoft.eShopWeb.PublicApi.MiddleWares
+{
+    public class ExceptionMiddleware
+    {
+        private readonly RequestDelegate _next;
+
+        public ExceptionMiddleware(RequestDelegate next)
+        {
+            _next = next;
+        }
+
+        public async Task InvokeAsync(HttpContext httpContext)
+        {
+            try
+            {
+                await _next(httpContext);
+            }
+            catch (Exception ex)
+            {
+                await HandleExceptionAsync(httpContext, ex);
+            }
+        }
+
+        private async Task HandleExceptionAsync(HttpContext context, Exception exception)
+        {
+            context.Response.ContentType = "application/json";
+
+            if (exception is DuplicateException duplicationException)
+            {
+                context.Response.StatusCode = (int)HttpStatusCode.Conflict;
+                await context.Response.WriteAsync(new ErrorDetails()
+                {
+                    StatusCode = context.Response.StatusCode,
+                    Message = duplicationException.Message
+                }.ToString());
+            }
+        }
+    }
+}

src/PublicApi/Startup.cs

@@ -14,6 +14,7 @@ using Microsoft.eShopWeb.Infrastructure.Data;
 using Microsoft.eShopWeb.Infrastructure.Identity;
 using Microsoft.eShopWeb.Infrastructure.Logging;
 using Microsoft.eShopWeb.Infrastructure.Services;
+using Microsoft.eShopWeb.PublicApi.MiddleWares;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
@@ -178,6 +179,8 @@ namespace Microsoft.eShopWeb.PublicApi
                 app.UseDeveloperExceptionPage();
             }
 
+            app.UseMiddleware<ExceptionMiddleware>();
+
             app.UseHttpsRedirection();
 
             app.UseRouting();