Catalog.API methods following more rest conventions:

Create/Update routed by POST/PUT & Location header returned
A new GET endpoint for returning single item by id created to honour Location header of previous methods.

src/Services/Catalog/Catalog.API/Controllers/CatalogController.cs

@@ -39,7 +39,7 @@ namespace Microsoft.eShopOnContainers.Services.Catalog.API.Controllers
                 .LongCountAsync();
 
             var itemsOnPage = await _catalogContext.CatalogItems
-                .OrderBy(c=>c.Name)
+                .OrderBy(c => c.Name)
                 .Skip(pageSize * pageIndex)
                 .Take(pageSize)
                 .ToListAsync();
@@ -47,11 +47,29 @@ namespace Microsoft.eShopOnContainers.Services.Catalog.API.Controllers
             itemsOnPage = ChangeUriPlaceholder(itemsOnPage);
 
             var model = new PaginatedItemsViewModel<CatalogItem>(
-                pageIndex, pageSize, totalItems, itemsOnPage);           
+                pageIndex, pageSize, totalItems, itemsOnPage);
 
             return Ok(model);
         }
 
+        [HttpGet]
+        [Route("items/{id:int}")]
+        public async Task<IActionResult> GetItemById(int id)
+        {
+            if (id <= 0)
+            {
+                return BadRequest();
+            }
+
+            var item = await _catalogContext.CatalogItems.SingleOrDefaultAsync(ci => ci.Id == id);
+            if (item != null)
+            {
+                return Ok(item);
+            }
+
+            return NotFound();
+        }
+
         // GET api/v1/[controller]/items/withname/samplename[?pageSize=3&pageIndex=10]
         [HttpGet]
         [Route("[action]/withname/{name:minlength(1)}")]
@@ -131,9 +149,9 @@ namespace Microsoft.eShopOnContainers.Services.Catalog.API.Controllers
             return Ok(items);
         }
 
-        //POST api/v1/[controller]/update
-        [Route("update")]
-        [HttpPost]
+        //PUT api/v1/[controller]/items
+        [Route("items")]
+        [HttpPut]
         public async Task<IActionResult> UpdateProduct([FromBody]CatalogItem productToUpdate)
         {
             var catalogItem = await _catalogContext.CatalogItems
@@ -141,13 +159,13 @@ namespace Microsoft.eShopOnContainers.Services.Catalog.API.Controllers
 
             if (catalogItem == null)
             {
-                return NotFound();
+                return NotFound(new { Message = $"Item with id {productToUpdate.Id} not found." });
             }
 
             var oldPrice = catalogItem.Price;
             var raiseProductPriceChangedEvent = oldPrice != productToUpdate.Price;
-            
-            
+
+
             // Update current product
             catalogItem = productToUpdate;
             _catalogContext.CatalogItems.Update(catalogItem);
@@ -156,40 +174,40 @@ namespace Microsoft.eShopOnContainers.Services.Catalog.API.Controllers
             {
                 //Create Integration Event to be published through the Event Bus
                 var priceChangedEvent = new ProductPriceChangedIntegrationEvent(catalogItem.Id, productToUpdate.Price, oldPrice);
-                
+
                 // Achieving atomicity between original Catalog database operation and the IntegrationEventLog thanks to a local transaction
                 await _catalogIntegrationEventService.SaveEventAndCatalogContextChangesAsync(priceChangedEvent);
-                
+
                 // Publish through the Event Bus and mark the saved event as published
                 await _catalogIntegrationEventService.PublishThroughEventBusAsync(priceChangedEvent);
             }
             else // Save updated product
             {
                 await _catalogContext.SaveChangesAsync();
-            }           
+            }
 
-            return Ok();
+            return CreatedAtAction(nameof(GetItemById), new { id = productToUpdate.Id }, null);
         }
 
-        //POST api/v1/[controller]/create
-        [Route("create")]
+        //POST api/v1/[controller]/items
+        [Route("items")]
         [HttpPost]
         public async Task<IActionResult> CreateProduct([FromBody]CatalogItem product)
         {
-            _catalogContext.CatalogItems.Add(
-                new CatalogItem
-                {
-                    CatalogBrandId = product.CatalogBrandId,
-                    CatalogTypeId = product.CatalogTypeId,
-                    Description = product.Description,
-                    Name = product.Name,
-                    PictureUri = product.PictureUri,
-                    Price = product.Price
-                });
+            var item = new CatalogItem
+            {
+                CatalogBrandId = product.CatalogBrandId,
+                CatalogTypeId = product.CatalogTypeId,
+                Description = product.Description,
+                Name = product.Name,
+                PictureUri = product.PictureUri,
+                Price = product.Price
+            };
+            _catalogContext.CatalogItems.Add(item);
 
             await _catalogContext.SaveChangesAsync();
 
-            return Ok();
+            return CreatedAtAction(nameof(GetItemById), new { id = item.Id }, null);
         }
 
         //DELETE api/v1/[controller]/id
@@ -202,13 +220,13 @@ namespace Microsoft.eShopOnContainers.Services.Catalog.API.Controllers
             if (product == null)
             {
                 return NotFound();
-            }            
+            }
 
             _catalogContext.CatalogItems.Remove(product);
 
             await _catalogContext.SaveChangesAsync();
 
-            return Ok();
+            return NoContent();
         }
 
         private List<CatalogItem> ChangeUriPlaceholder(List<CatalogItem> items)