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RESTful APIs in the Real World Course 2

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This tutorial uses a deprecated micro-framework called Silex. The fundamentals of REST are still ?valid, but the code we use can't be used in a real application.

Reuse and Consistency

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Now I want to do a couple of other cleanup things. First: whenever we need to read information off of the request that the client is sending us, we're going to use this same json_decode for the content:

31 lines src/KnpU/CodeBattle/Controller/Api/TokenController.php
... lines 1 - 16
public function newAction(Request $request)
... lines 18 - 20
$data = json_decode($request->getContent(), true);
... lines 22 - 28
}
... lines 30 - 31

In fact, we use this in ProgrammerController inside of the handleRequest method.:

168 lines src/KnpU/CodeBattle/Controller/Api/ProgrammerController.php
... lines 1 - 123
private function handleRequest(Request $request, Programmer $programmer)
{
$data = json_decode($request->getContent(), true);
... lines 127 - 154
}
... lines 156 - 168

So we have the same logic duplicated there. Let's centralize this by putting it into our BaseController. Open this up and create a new protected function at the bottom called decodeRequestBodyIntoParameters. I know, really short name. And we'll take in a Request object as an argument. And at first this is going to be really simple. We can go to the TokenController, grab this json_decode line, go back to BaseController and return it:

290 lines src/KnpU/CodeBattle/Controller/BaseController.php
... lines 1 - 269
protected function decodeRequestBodyIntoParameters(Request $request)
{
... lines 272 - 275
$data = json_decode($request->getContent(), true);
if ($data === null) {
$problem = new ApiProblem(
400,
ApiProblem::TYPE_INVALID_REQUEST_BODY_FORMAT
);
throw new ApiProblemException($problem);
}
... lines 285 - 287
}
... lines 289 - 290

So now in the TokenController, $data = $this->decodeRequestBodyIntoParameters($request) and we've got it.

So just to be sure, let's go back and run our entire feature:

php vendor/bin/behat features/api/token.feature

Consistently Erroring on Invalid JSON

Everything still passes so we're good. So, why did we do this? Back in ProgrammerController, when we decoded the body in handleRequest, we also checked to see if maybe the json that was sent to us had a bad format. If the JSON is bad, then json_decode is going to return null which is what we're checking for here:

168 lines src/KnpU/CodeBattle/Controller/Api/ProgrammerController.php
... lines 1 - 123
private function handleRequest(Request $request, Programmer $programmer)
{
$data = json_decode($request->getContent(), true);
$isNew = !$programmer->id;
if ($data === null) {
$problem = new ApiProblem(
400,
ApiProblem::TYPE_INVALID_REQUEST_BODY_FORMAT
);
throw new ApiProblemException($problem);
}
... lines 136 - 154
}
... lines 156 - 168

So let's move that into our new BaseController method, because that is a really nice check. And then it's creating an ApiProblem and throwing an ApiProblemException so we can have that really nice consistent format. We just need to add the use statements for both of these:

290 lines src/KnpU/CodeBattle/Controller/BaseController.php
... lines 1 - 269
protected function decodeRequestBodyIntoParameters(Request $request)
{
... lines 272 - 275
$data = json_decode($request->getContent(), true);
if ($data === null) {
$problem = new ApiProblem(
400,
ApiProblem::TYPE_INVALID_REQUEST_BODY_FORMAT
);
throw new ApiProblemException($problem);
}
... lines 285 - 287
}
... lines 289 - 290

Perfect. Let's rerun those again to make sure things are happy ... and they are!

Don't Blow up on an Empty Request Body!

One other little detail here is that if the request body is blank this is going to blow up with an invalid request body format because json_decode is going to return null. Now technically sending a blank request is not invalid json so I don't want to blow up in that way. This doesn't affect anything now but it's planning for the future. So if !$request->getContent(), then just set $data to an array. Else, we'll do all of our logic down here that actually decodes the json:

290 lines src/KnpU/CodeBattle/Controller/BaseController.php
... lines 1 - 269
protected function decodeRequestBodyIntoParameters(Request $request)
{
// allow for a possibly empty body
if (!$request->getContent()) {
$data = array();
} else {
$data = json_decode($request->getContent(), true);
if ($data === null) {
$problem = new ApiProblem(
400,
ApiProblem::TYPE_INVALID_REQUEST_BODY_FORMAT
);
throw new ApiProblemException($problem);
}
}
... line 287
}
... lines 289 - 290

And just to make sure we didn't screw anything up, we'll rerun the tests.

php vendor/bin/behat features/api/token.feature

A ParameterBag Makes Life Nicer

One last little thing that is going to make our code even easier to deal with. Back in TokenController, because the decodeRequestBodyIntoParameters returns an array, we need to code a bit more defensively here. What if they don't actually send a notes key, we don't want some sort of PHP error:

31 lines src/KnpU/CodeBattle/Controller/Api/TokenController.php
... lines 1 - 16
public function newAction(Request $request)
{
... lines 19 - 20
$data = json_decode($request->getContent(), true);
... lines 22 - 23
$token->notes = $data['notes'];
... lines 25 - 28
}
... lines 30 - 31

The horror!

And that's not that big of a deal but it's kind of annoying and error prone. So instead, in our new function I want to return a different type of object called a ParameterBag:

290 lines src/KnpU/CodeBattle/Controller/BaseController.php
... lines 1 - 269
protected function decodeRequestBodyIntoParameters(Request $request)
{
// allow for a possibly empty body
if (!$request->getContent()) {
$data = array();
} else {
$data = json_decode($request->getContent(), true);
... lines 277 - 284
}
... line 286
return new ParameterBag($data);
}
... lines 289 - 290

This comes from a component inside of Symfony that Silex uses. It's an object but it acts just like an array with some extra nice methods. Let me show you what I mean, back in TokenController instead of using it like an array we can now say $data->get() and if that key doesn't exist it's not going to throw some bad index warning. We can also use the second argument as the default value:

31 lines src/KnpU/CodeBattle/Controller/Api/TokenController.php
... lines 1 - 16
public function newAction(Request $request)
{
... lines 19 - 20
$data = $this->decodeRequestBodyIntoParameters($request);
... line 22
$token = new ApiToken($this->getLoggedInUser()->id);
$token->notes = $data->get('notes');
... lines 25 - 28
}
... lines 30 - 31

Nice, so once again let's rerun the tests and everything's happy!

Use decodeRequestBodyIntoParameters in all the Places

We have this really nice new function inside of our BaseController and I also want to take advantage of it inside of our ProgrammerController. We're going down to handleRequest and now we can just say $data = $this->decodeRequestBodyIntoParameters() and pass the $request object:

159 lines src/KnpU/CodeBattle/Controller/Api/ProgrammerController.php
... lines 1 - 123
private function handleRequest(Request $request, Programmer $programmer)
{
$data = $this->decodeRequestBodyIntoParameters($request);
... lines 127 - 145
}
... lines 147 - 159

Next, this big if block is no longer needed. And now because data is an object instead of an array, we need to update our two or three usages of it down here, which is going to make things simpler. So instead of using the isset function, we can say if(!$data->has($property)) because that's one of the methods on that ParameterBag object. And down here instead of having to code defensively using isset, we can just say $data->get($property). In fact let's just do this all in one line:

159 lines src/KnpU/CodeBattle/Controller/Api/ProgrammerController.php
... lines 1 - 123
private function handleRequest(Request $request, Programmer $programmer)
{
$data = $this->decodeRequestBodyIntoParameters($request);
... lines 127 - 134
// update the properties
foreach ($apiProperties as $property) {
// if a property is missing on PATCH, that's ok - just skip it
if (!$data->has($property) && $request->isMethod('PATCH')) {
continue;
}
$programmer->$property = $data->get($property);
}
... lines 144 - 145
}
... lines 147 - 159

Lovely! Now that was a fairly fundamental change so there is a good chance that we broke something. So let's go back and run our entire programmer feature:

php vendor/bin/behat features/api/programmer.feature

Beautiful! We didn't actually break anything which is so good to know.

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This tutorial uses a deprecated micro-framework called Silex. The fundamentals of REST are still ?valid, but the code we use can't be used in a real application.
Silex

What PHP libraries does this tutorial use?

// composer.json
{
    "require": {
        "silex/silex": "~1.0", // v1.3.2
        "symfony/twig-bridge": "~2.1", // v2.7.3
        "symfony/security": "~2.4", // v2.7.3
        "doctrine/dbal": "^2.5.4", // v2.5.4
        "monolog/monolog": "~1.7.0", // 1.7.0
        "symfony/validator": "~2.4", // v2.7.3
        "symfony/expression-language": "~2.4", // v2.7.3
        "jms/serializer": "~0.16", // 0.16.0
        "willdurand/hateoas": "~2.3" // v2.3.0
    },
    "require-dev": {
        "behat/mink": "~1.5", // v1.5.0
        "behat/mink-goutte-driver": "~1.0.9", // v1.0.9
        "behat/mink-selenium2-driver": "~1.1.1", // v1.1.1
        "behat/behat": "~2.5", // v2.5.5
        "behat/mink-extension": "~1.2.0", // v1.2.0
        "phpunit/phpunit": "~5.7.0", // 5.7.27
        "guzzle/guzzle": "~3.7" // v3.9.3
    }
}
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