POST: Creation, Location Header and 201

Video not working?

It looks like your browser may not support the H264 codec. If you're using Linux, try a different browser or try installing the gstreamer0.10-ffmpeg gstreamer0.10-plugins-good packages.

Thanks! This saves us from needing to use Flash or encode videos in multiple formats. And that let's us get back to making more videos :). But as always, please feel free to message us.

POST: Creation, Location Header and 201

Once the POST endpoint works, the client will send programmer details to the server. In REST-speak, it will send a representation of a programmer, which can be done in a bunch of different ways. It’s invisible to us, but HTML forms do this by sending data in a format called application/x-www-form-urlencoded:

POST /api/programmers HTTP/1.1
Host: localhost:8000
Content-Type: application/x-www-form-urlencoded

nickname=Geek+Dev1&avatarNumber=5

PHP reads this and puts it into the $_POST array. That’s ok for the web, but in the API world, it’s ugly. Why not, have the client send us the representation in a beautiful bouquet of curly braces known as JSON:

POST /api/programmers HTTP/1.1
Host: localhost:8000
Content-Type: application/json

{
    "nickname": "Geek Dev1",
    "avatarNumber": 5
}

Creating a request like this with Guzzle is easy:

// testing.php
// ...

$nickname = 'ObjectOrienter'.rand(0, 999);
$data = array(
    'nickname' => $nickname,
    'avatarNumber' => 5,
    'tagLine' => 'a test dev!'
);

$request = $client->post('/api/programmers', null, json_encode($data));
$response = $request->send();

echo $response;
echo "\n\n";

The second null argument is the request headers to send. We’re not worried about headers yet, so we can just leave it blank.

Coding up the Endpoint

Back in the ProgrammerController class, let’s make this work by doing our favorite thing - coding! First, how do we get the JSON string passed in the request? In Silex, you do this by getting the Request object and calling getContent() on it. Let’s just return the data from the endpoint so we can see it:

// src/KnpU/CodeBattle/Controller/Api/ProgrammerController.php
// ...

public function newAction(Request $request)
{
    $data = $request->getContent();
    return $data;
}

Tip

Your framework will likely have a shortcut for getting the request content or body. But if it doesn’t, you can get it by using this strange bit of code:

$data = file_get_contents('php://input');

This is a special stream that reads the request body. For more details, see php.net: php://.

Try running our testing.php file again:

$ php testing.php

This time, we see the JSON string being echo’ed right back at us:

HTTP/1.1 200 OK
...
Content-Type: text/html; charset=UTF-8

{"nickname":"ObjectOrienter31","avatarNumber":5}

Creating the Programmer Resource Object

Awesome! I’ve already created a Programmer class, which has just a few properties on it. I also created simple classes for the other two resources - Project and Battle. We’ll use these later.

In newAction, we have the JSON string, so let’s decode it and use the data to create a new Programmer object that’s ready for battle. We’ll use each key that the client sends to populate a property on the object:

// src/KnpU/CodeBattle/Controller/Api/ProgrammerController.php
// ...

public function newAction(Request $request)
{
    $data = json_decode($request->getContent(), true);

    $programmer = new Programmer($data['nickname'], $data['avatarNumber']);
    $programmer->tagLine = $data['tagLine'];
    // ...
}

Note

Do not forget to add use KnpU\CodeBattle\Model\Programmer; namespace for the Programmer class at the beginning of the ProgrammerController.php.

My app also has a really simple ORM that lets us save these objects to the database. How you save things to your database will be different. The key point is that we have a Programmer class that models how we want our API to look, and that we can somehow save this:

// src/KnpU/CodeBattle/Controller/Api/ProgrammerController.php
// ...

public function newAction(Request $request)
{
    $data = json_decode($request->getContent(), true);

    $programmer = new Programmer($data['nickname'], $data['avatarNumber']);
    $programmer->tagLine = $data['tagLine'];
    $programmer->userId = $this->findUserByUsername('weaverryan')->id;

    $this->save($programmer);

    return 'It worked. Believe me - I\'m an API';
}

At the bottom, I’m just returning a really reassuring message that everything went ok.

Faking the Authenticated User

I’ve also added one really ugly detail:

$programmer->userId = $this->findUserByUsername('weaverryan')->id;

Every programmer is created and owned by one user. On the web, finding out who is creating the programmer is as easy as finding out which user is currently logged in.

But our API has no idea who we are - we’re just a client making requests without any identification.

We’ll fix this later. Right now, I’ll just make every programmer owned by me. Make sure to use my username: it’s setup as test data that’s always in our database. This test data is also known as fixtures.

Ok, the moment of truth! Run the testing script again:

$ php testing.php
HTTP/1.1 200 OK
Host: localhost:8000
...
Content-Type: text/html; charset=UTF-8

It worked. Believe me - I'm an API

The message tells us that it probably worked. And if you login as weaverryan with password foo on the web, you’ll see this fierce programmer-warrior in the list.

Status Code 201

But no time to celebrate! Our response is a little sad. First, since we’ve just created a resource, the HTTP elders say that we should return a 201 status code. In Silex, we just need to return a new Response object and set the status code as the second argument:

// src/KnpU/CodeBattle/Controller/Api/ProgrammerController.php
// ...

public function newAction(Request $request)
{
    // ...
    $this->save($programmer);

    return new Response('It worked. Believe me - I\'m an API', 201);
}

Running the testing script this time shows us a 201 status code.

Location Header

And when we use the 201 status code, there’s another rule: include a Location header that points to the new resource. Hmm, we don’t have an endpoint to get a single programmer representation yet. To avoid angering the RESTful elders, let’s add a location header, and just fake the URL for now:

// src/KnpU/CodeBattle/Controller/Api/ProgrammerController.php
// ...

public function newAction(Request $request)
{
    // ...
    $this->save($programmer);

    $response = new Response('It worked. Believe me - I\'m an API', 201);
    $response->headers->set('Location', '/some/programmer/url');

    return $response;
}

If you stop and think about it, this is how the web works. When we submit a form to create a programmer, the server returns a redirect that takes us to the page to view it. In an API, the status code is 201 instead of 301 or 302, but the server is trying to help show us the way in both cases.

Try the final product out in our test script:

$ php testing.php
HTTP/1.1 201 Created
...
Location: /some/programmer/url
Content-Type: text/html; charset=UTF-8

It worked. Believe me - I'm an API

Other than the random text we’re still returning, this endpoint is looking great. Now to GET a programmer!

Leave a comment!