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02.

Sending back Validation Errors

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Time to add validation errors and get this test passing. First, add the validation. Open the Programmer class. There's no validation stuff here yet, so we need the use statement for it. I'll use the NotBlank class directly, let PhpStorm auto-complete that for me, then remove the last part and add as Assert:

190 lines | src/AppBundle/Entity/Programmer.php
// ... lines 1 - 6
use Symfony\Component\Validator\Constraints as Assert;
// ... lines 8 - 190

That's a little shortcut to get that use statement you always need for validation.

Now, above username, add @Assert\NotBlank with a message option. Go back and copy the clever message and paste it here:

190 lines | src/AppBundle/Entity/Programmer.php
// ... lines 1 - 15
class Programmer
{
// ... lines 18 - 26
/**
// ... lines 28 - 31
* @Assert\NotBlank(message="Please enter a clever nickname")
*/
private $nickname;
// ... lines 35 - 188
}

Handling Validation in the Controller

Ok! That was step 1. Step 2 is to go into the controller and send the validation errors back to the user. We're using forms, so handling validation is going to look pretty much identical to how it looks in traditional web forms.

Check out that processForm() function we created in episode 1:

145 lines | src/AppBundle/Controller/Api/ProgrammerController.php
// ... lines 1 - 15
class ProgrammerController extends BaseController
{
// ... lines 18 - 136
private function processForm(Request $request, FormInterface $form)
{
$data = json_decode($request->getContent(), true);
$clearMissing = $request->getMethod() != 'PATCH';
$form->submit($data, $clearMissing);
}
}

All this does is json_decode the request body and call $form->submit(). That does the same thing as $form->handleRequest(), which you're probably familiar with. So after this function is called, the form processing has happened. After it, add an if statement with the normal if (!$form->isValid()):

145 lines | src/AppBundle/Controller/Api/ProgrammerController.php
// ... lines 1 - 15
class ProgrammerController extends BaseController
{
// ... lines 18 - 21
public function newAction(Request $request)
{
// ... lines 24 - 25
$this->processForm($request, $form);
if (!$form->isValid()) {
// ... lines 29 - 30
}
// ... lines 32 - 46
}
// ... lines 48 - 143
}

Tip

Calling just $form->isValid() before submitting the form is deprecated and will raise an exception in Symfony 4.0. Use $form->isSubmitted() && $form->isValid() instead to avoid the exception.

If we find ourselves here, it means we have validation errors. Let's see if this is working. Use the dump() function and the $form->getErrors() function, passing it true and false as arguments. That'll give us all the errors in a big tree. Cast this to a string - getErrors() returns a FormErrorIterator object, which has a nice __toString() method. Add a die at the end:

145 lines | src/AppBundle/Controller/Api/ProgrammerController.php
// ... lines 1 - 21
public function newAction(Request $request)
{
// ... lines 24 - 27
if (!$form->isValid()) {
// ... line 29
dump((string) $form->getErrors(true, false));die;
}
// ... lines 32 - 46
}
// ... lines 48 - 145

Let's run our test to see what this looks like. Copy the testValidationErrors method name, then run:

php bin/phpunit -c app --filter testValidationErrors

Ok, there's our printed dump. Woh, that is ugly. That's the nice HTML formatting that comes from the dump() function. But it's unreadable here. I'll show you a trick to clean that up.

It's dumping HTML because it detects that something is accessing it via the web interface. But we kinda want it to print nicely for the terminal. Above the dump() function, add header('Content-Type: cli'):

145 lines | src/AppBundle/Controller/Api/ProgrammerController.php
// ... lines 1 - 27
if (!$form->isValid()) {
header('Content-Type: cli');
dump((string) $form->getErrors(true, false));die;
}
// ... lines 32 - 145

That's a hack - but try the test now:

bin/phpunit -c app --filter testValidationErrors

Ok, that's a sweet looking dump. We've got the validation error for the nickname field and another for a missing CSRF token - we'll fix that soon. But, validation is working.

Collecting the Validation Errors

So now we just need to collect those errors and put them into a JSON response. To help with that, I'm going to paste a new private function into the bottom of ProgrammerController:

170 lines | src/AppBundle/Controller/Api/ProgrammerController.php
// ... lines 1 - 10
use Symfony\Component\Form\FormInterface;
// ... lines 12 - 15
class ProgrammerController extends BaseController
{
// ... lines 18 - 151
private function getErrorsFromForm(FormInterface $form)
{
$errors = array();
foreach ($form->getErrors() as $error) {
$errors[] = $error->getMessage();
}
foreach ($form->all() as $childForm) {
if ($childForm instanceof FormInterface) {
if ($childErrors = $this->getErrorsFromForm($childForm)) {
$errors[$childForm->getName()] = $childErrors;
}
}
}
return $errors;
}
}

If you're coding with me, you'll find this in a code block on this page - copy it from there. Actually, I adapted this from some code in FOSRestBundle.

A Form object is a collection of other Form objects - one for each field. And sometimes, fields have sub-fields, which are yet another level of Form objects. It's a tree. And when validation runs, it attaches the errors to the Form object of the right field. That's the treky, I mean techy, explanation of this function: it recursively loops through that tree, fetching the errors off of each field to create an associative array of those errors.

Head back to newAction() and use this: $errors = $this->getErrorsFromForm() and pass it the $form object. Now, create a $data array that will eventually be our JSON response.

170 lines | src/AppBundle/Controller/Api/ProgrammerController.php
// ... lines 1 - 21
public function newAction(Request $request)
{
// ... lines 24 - 27
if (!$form->isValid()) {
$errors = $this->getErrorsFromForm($form);
$data = [
// ... lines 32 - 34
];
// ... lines 36 - 37
}
// ... lines 39 - 53
}
// ... lines 55 - 170

Remember, we want type, title and errors keys. Add a type key: this is the machine name of what went wrong. How about validation_error - I'm making that up. For title - we'll have the human-readable version of what went wrong. Let's use: "There was a validation error". And for errors pass it the $errors array.

Finish it off! Return a new JsonResponse() with $data and the 400 status code:

170 lines | src/AppBundle/Controller/Api/ProgrammerController.php
// ... lines 1 - 21
public function newAction(Request $request)
{
// ... lines 24 - 27
if (!$form->isValid()) {
$errors = $this->getErrorsFromForm($form);
$data = [
'type' => 'validation_error',
'title' => 'There was a validation error',
'errors' => $errors
];
return new JsonResponse($data, 400);
}
// ... lines 39 - 53
}
// ... lines 55 - 170

Phew! Let's give it a try:

bin/phpunit -c app --filter testValidationErrors

Oof! That's not passing! That's a huge error. The dumped response looks perfect. The error started on ProgrammerControllerTest where we use assertResponsePropertiesExist(). Whoops! And there's the problem - I had assertResponsePropertyExists() - what you use to check for a single field. Make sure your's says assertResponsePropertiesExist().

Try it again:

bin/phpunit -c app --filter testValidationErrors

It's passing! Let's pretend I made that mistake on purpose - it was nice because we could see that the dumped response looks exactly like we wanted.