Exercise – Implement CRUD operations

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

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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:

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C#

[HttpPost]
public IActionResult Create(Pizza pizza)
{            
    PizzaService.Add(pizza);
    return CreatedAtAction(nameof(Get), 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.

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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, as explained in the previous unit.

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Modify a pizza

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

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

C#

[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.

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 Note

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

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Remove a pizza

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

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

C#

[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,

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Build and run the finished web API

Build and start the web API by running the following command:

.NET CLI

dotnet run

Test the finished web API with HTTP files

1. Reopen the ContosoPizza.http file.
2. Make a POST request to add a new pizza in HttpRepl by using the following command:OutputPOST {{ContosoPizza_HostAddress}}/pizza/ Content-Type: application/json { "name": "Hawaii", "isGlutenFree": false } ### The preceding command returns the newly created pizza:OutputHTTP/1.1 201 Created Connection: close Content-Type: application/json; charset=utf-8 Date: Wed, 17 Jan 2024 17:03:02 GMT Server: Kestrel Location: http://localhost:5192/Pizza/3 Transfer-Encoding: chunked { "id": 3, "name": "Hawaii", "isGlutenFree": false }
3. Update the new Hawaii pizza to a Hawaiian pizza with a PUT request by using the following command:OutputPUT {{ContosoPizza_HostAddress}}/pizza/3 Content-Type: application/json { "id": 3, "name": "Hawaiian", "isGlutenFree": false } ### The preceding command returns the following output that indicates success:OutputHTTP/1.1 204 No Content Connection: close Date: Wed, 17 Jan 2024 17:07:30 GMT Server: Kestrel To verify that the pizza was updated, rerun the GET action by using the following command:OutputGET {{ContosoPizza_HostAddress}}/pizza/3 Accept: application/json ### The preceding command returns the newly updated pizza:OutputHTTP/1.1 200 OK Connection: close Content-Type: application/json; charset=utf-8 Date: Wed, 17 Jan 2024 17:09:01 GMT Server: Kestrel Transfer-Encoding: chunked { "id": 3, "name": "Hawaiian", "isGlutenFree": false }
4. Our API can also delete the newly created pizza through the DELETE action if you run the following command:.NET CLIDELETE {{ContosoPizza_HostAddress}}/pizza/3 ### The preceding command returns a 204 No Content result for success:OutputHTTP/1.1 204 No Content Date: Fri, 02 Apr 2021 23:30:04 GMT Server: Kestrel To verify that the pizza was removed, rerun the GET action by using the following command:.NET CLIGET {{ContosoPizza_HostAddress}}/pizza/ Accept: application/json ### The preceding command returns the original pizzas as results:OutputHTTP/1.1 200 OK Content-Type: application/json; charset=utf-8 Date: Fri, 02 Apr 2021 23:31:15 GMT Server: Kestrel Transfer-Encoding: chunked [ { "id": 1, "name": "Classic Italian", "isGlutenFree": false }, { "id": 2, "name": "Veggie", "isGlutenFree": true } ]

You’re now finished implementing and testing a newly created web API built with ASP.NET Core.

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Optional: Test the finished web API with Command Line HTTPREPL

1. Reopen the existing httprepl terminal, or open a new integrated terminal from Visual Studio Code by selecting Terminal > New Terminal from the main menu.
2. If you opened a new terminal, connect to the web API by running the following command:.NET CLIhttprepl https://localhost:{PORT} Alternatively, run the following command at any time while HttpRepl is running:.NET CLIconnect https://localhost:{PORT}
3. Go to the Pizza endpoint by running the following command:.NET CLIcd Pizza
4. Run the following command to see the new actions on the Pizza API:.NET CLIls The preceding command shows an output of available APIs for the Pizza endpoint:Output https://localhost:{PORT}/Pizza> ls . [GET|POST] .. [] {id} [GET|PUT|DELETE]
5. Make a POST request to add a new pizza in HttpRepl by using the following command:.NET CLIpost -c "{"name":"Hawaii", "isGlutenFree":false}" The preceding command returns the newly created pizza:OutputHTTP/1.1 201 Created Content-Type: application/json; charset=utf-8 Date: Fri, 02 Apr 2021 23:23:09 GMT Location: https://localhost:{PORT}/Pizza?id=3 Server: Kestrel Transfer-Encoding: chunked { "id": 3, "name": "Hawaii", "isGlutenFree": false }
6. Update the new Hawaii pizza to a Hawaiian pizza with a PUT request by using the following command:.NET CLIput 3 -c "{"id": 3, "name":"Hawaiian", "isGlutenFree":false}" The preceding command returns the following output that indicates success:OutputHTTP/1.1 204 No Content Date: Fri, 02 Apr 2021 23:23:55 GMT Server: Kestrel To verify that the pizza was updated, rerun the GET action by using the following command:.NET CLIget 3 The preceding command returns the newly updated pizza:OutputHTTP/1.1 200 OK Content-Type: application/json; charset=utf-8 Date: Fri, 02 Apr 2021 23:27:37 GMT Server: Kestrel Transfer-Encoding: chunked { "id": 3, "name": "Hawaiian", "isGlutenFree": false }
7. Our API can also delete the newly created pizza through the DELETE action if you run the following command:.NET CLIdelete 3 The preceding command returns a 204 No Content result for success:OutputHTTP/1.1 204 No Content Date: Fri, 02 Apr 2021 23:30:04 GMT Server: Kestrel To verify that the pizza was removed, rerun the GET action by using the following command:.NET CLIget The preceding command returns the original pizzas as results:OutputHTTP/1.1 200 OK Content-Type: application/json; charset=utf-8 Date: Fri, 02 Apr 2021 23:31:15 GMT Server: Kestrel Transfer-Encoding: chunked [ { "id": 1, "name": "Classic Italian", "isGlutenFree": false }, { "id": 2, "name": "Veggie", "isGlutenFree": true } ]

You’re now finished implementing and testing a newly created web API built with ASP.NET Core.

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