Implement CRUD

Implement CRUD operation

Let's continue extending our web API controller to add the ability to create (POST), update (PUT), and delete (DELETE) pizza from our inventory.

Add a pizza

Let's enable a pizza to be added through the web API by using a POST method.

Replace the // POST action comment in Controllers/PizzaController.cs with the following code:

[HttpPost]
public IActionResult Create(Pizza pizza)
{            
    PizzaService.Add(pizza);
    return CreatedAtAction(nameof(Create), new { id = pizza.Id }, pizza);
}

The preceding action:

• Responds only to the HTTP POST verb, as denoted by the [HttpPost] attribute.

• Inserts the request body's Pizza object into the in-memory cache.

Note

Because the controller is annotated with the [ApiController] attribute, it's implied that the Pizza parameter will be found in the request body.

The first parameter in the CreatedAtAction method call represents an action name. The nameof keyword is used to avoid hard-coding the action name. CreatedAtAction uses the action name to generate a location HTTP response header with a URL to the newly created pizza.

Modify a pizza

Now, let's enable a pizza to be updated through the web API by using a PUT method.

Replace the // PUT action comment in Controllers/PizzaController.cs with the following code:

[HttpPut("{id}")]
public IActionResult Update(int id, Pizza pizza)
{
    if (id != pizza.Id)
        return BadRequest();
           
    var existingPizza = PizzaService.Get(id);
    if(existingPizza is null)
        return NotFound();
   
    PizzaService.Update(pizza);           
   
    return NoContent();
}

The preceding action:

• Responds only to the HTTP PUT verb, as denoted by the [HttpPut] attribute.

• Requires that the id parameter's value is included in the URL segment after pizza/.

• Returns IActionResult, because the ActionResult return type isn't known until runtime. The BadRequest, NotFound, and NoContent methods return BadRequestResult, NotFoundResult, and NoContentResult types, respectively.

Note

Because the controller is annotated with the [ApiController] attribute, it's implied that the Pizza parameter will be found in the request body.

Remove a pizza

Finally, let's enable a pizza to be removed through the web API by using a DELETE method.

Replace the // DELETE action comment in Controllers/PizzaController.cs with the following code:

[HttpDelete("{id}")]
public IActionResult Delete(int id)
{
    var pizza = PizzaService.Get(id);
   
    if (pizza is null)
        return NotFound();
       
    PizzaService.Delete(id);
   
    return NoContent();
}

The preceding action:

• Responds only to the HTTP DELETE verb, as denoted by the [HttpDelete] attribute.

• Requires that the id parameter's value is included in the URL segment after pizza/.

• Returns IActionResult because the ActionResult return type isn't known until runtime. The NotFound and NoContent methods return NotFoundResult and NoContentResult types, respectively.

• Queries the in-memory cache for a pizza that matches the provided id parameter.

Remember to save the Controllers/PizzaController.cs file before proceeding,

Build and run the finished web API

Try to create a pizza as shown:

Note how the new pizza is shown in the response body and also a location Uri is created for pizza 3. This is required when clients want to do more with the new object!

You can also see the newly created pizza if you do a get request for showing all pizzas. Note that this has to be done before you stop the application since we don't have a backing database and we are reading from cache!

Similarly, you can try editing and deleting a pizza!

Videos for learning more

• .NET 101

• ASP.NET Core Web API 101

• ASP.NET Core 101