> APIs > API Platform 3 Part 3: Custom Resources
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24.

DTO Validation & Security

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Let's talk about validation! When we ->post() to our endpoint, the internal object will be our UserApi object... which means that's what will be validated. Watch. Send no fields to the POST request... and run that test:

symfony php bin/phpunit --filter=testPostToCreateUser

Oh uh: 500 error! And... I bet you can guess why. It says:

User::setEmail(): Argument #1 ($email) must be of type string

Coming from our state processor on line 59. Because there are no validation constraints at all on UserApi, the email property remains null. Then, over here on line 59, we try to transfer that null email onto our entity. It doesn't like that, there's a short fist fight, and we see this error. And even if it did accept a null value, it would eventually fail in the database because the email isn't allowed to be null there.

We're missing validation. Fortunately, it's easy to add... once you know that validation will happen on the UserApi object, not the entity.

Configuration the Operations

But before we run wild and add constraints, let's specify the operations... so we only have the ones we need: new Get(), new GetCollection(), new Post()... we'll add some config to that in a moment... as well as new Patch() and new Delete().

68 lines | src/ApiResource/UserApi.php
// ... lines 1 - 9
use ApiPlatform\Metadata\Delete;
use ApiPlatform\Metadata\Get;
use ApiPlatform\Metadata\GetCollection;
use ApiPlatform\Metadata\Patch;
use ApiPlatform\Metadata\Post;
// ... lines 15 - 20
#[ApiResource(
// ... line 22
operations: [
new Get(),
new GetCollection(),
new Post(
// ... line 27
),
new Patch(),
new Delete(),
],
// ... lines 32 - 35
)]
// ... lines 37 - 39
class UserApi
{
// ... lines 42 - 66
}

Back when our User entity was the #[ApiResource], the Post() operation had an extra validationContext option with groups set to Default and postValidation.

68 lines | src/ApiResource/UserApi.php
// ... lines 1 - 9
use ApiPlatform\Metadata\Delete;
use ApiPlatform\Metadata\Get;
use ApiPlatform\Metadata\GetCollection;
use ApiPlatform\Metadata\Patch;
use ApiPlatform\Metadata\Post;
// ... lines 15 - 20
#[ApiResource(
// ... line 22
operations: [
new Get(),
new GetCollection(),
new Post(
validationContext: ['groups' => ['Default', 'postValidation']],
),
new Patch(),
new Delete(),
],
// ... lines 32 - 35
)]
// ... lines 37 - 39
class UserApi
{
// ... lines 42 - 66
}

Thanks to that, when the Post() operation happened, it would run all the normal validators plus any that were in this postValidation group. We'll see why we need that in a moment.

Adding the Constraints

Ok, constraint time! $id isn't even writable... we want $email to be #[NotBlank]... and be an #[Email].

68 lines | src/ApiResource/UserApi.php
// ... lines 1 - 18
use Symfony\Component\Validator\Constraints as Assert;
// ... lines 20 - 39
class UserApi
{
// ... lines 42 - 44
#[Assert\NotBlank]
#[Assert\Email]
public ?string $email = null;
// ... lines 48 - 66
}

We want $username to be #[NotBlank]...

68 lines | src/ApiResource/UserApi.php
// ... lines 1 - 18
use Symfony\Component\Validator\Constraints as Assert;
// ... lines 20 - 39
class UserApi
{
// ... lines 42 - 44
#[Assert\NotBlank]
#[Assert\Email]
public ?string $email = null;
#[Assert\NotBlank]
public ?string $username = null;
// ... lines 51 - 66
}

then $password is an interesting one. $password should be allowed to be blank if we're doing a PATCH request to edit it... but required on a POST request. To accomplish that, add #[NotBlank] but with a groups option set to postValidation.

68 lines | src/ApiResource/UserApi.php
// ... lines 1 - 18
use Symfony\Component\Validator\Constraints as Assert;
// ... lines 20 - 39
class UserApi
{
// ... lines 42 - 44
#[Assert\NotBlank]
#[Assert\Email]
public ?string $email = null;
#[Assert\NotBlank]
public ?string $username = null;
// ... lines 51 - 55
#[Assert\NotBlank(groups: ['postValidation'])]
public ?string $password = null;
// ... lines 58 - 66
}

This constraint will only be run when we're validating the postValidation group... which means it will only be run for the Post() operation.

Okay, that should do it! Run the test now:

symfony php bin/phpunit --filter=testPostToCreateUser

And... a beautiful 422 status code!

UniqueEntity constraint?

By the way, one of the other validation constraints we had before on the User entity was #[UniqueEntity]. That prevented someone from creating two users with the same email or username. I don't have that on UserApi, but we should. The #[UniqueEntity] constraint, unfortunately, only works on entities... so we'd need to create a custom validator to have that on UserApi. We're not going to worry about that right, but I wanted to point it out.

Anyway, back over on the test, re-add the fields. Validation, check!

Adding Security

The next thing we need to re-add - code that used to live on User - is security. Up here on the API level, for the entire resource, require is_granted("ROLE_USER").

72 lines | src/ApiResource/UserApi.php
// ... lines 1 - 20
#[ApiResource(
// ... lines 22 - 35
security: 'is_granted("ROLE_USER")',
// ... lines 37 - 39
)]
// ... lines 41 - 43
class UserApi
{
// ... lines 46 - 70
}

This means that we need to be logged in to use any of the operations for this resource... by default. Then we overrode that. In Post(), we definitely can't be logged in yet because we're registering our user. Say, security set to is_granted("PUBLIC_ACCESS") which is a special attribute that will always pass.

72 lines | src/ApiResource/UserApi.php
// ... lines 1 - 20
#[ApiResource(
// ... line 22
operations: [
// ... lines 24 - 25
new Post(
security: 'is_granted("PUBLIC_ACCESS")',
// ... line 28
),
// ... lines 30 - 33
],
// ... line 35
security: 'is_granted("ROLE_USER")',
// ... lines 37 - 39
)]
// ... lines 41 - 43
class UserApi
{
// ... lines 46 - 70
}

Down here for Patch(), we had security('is_granted("ROLE_USER_EDIT")').

72 lines | src/ApiResource/UserApi.php
// ... lines 1 - 20
#[ApiResource(
// ... line 22
operations: [
// ... lines 24 - 25
new Post(
security: 'is_granted("PUBLIC_ACCESS")',
// ... line 28
),
new Patch(
security: 'is_granted("ROLE_USER_EDIT")'
),
// ... line 33
],
// ... line 35
security: 'is_granted("ROLE_USER")',
// ... lines 37 - 39
)]
// ... lines 41 - 43
class UserApi
{
// ... lines 46 - 70
}

In our app, we decided that you need to have this special tole to be able to edit users.

Ok! Let's run all the tests for User:

symfony php bin/phpunit tests/Functional/UserResourceTest.php

And... oh. Not bad! Three out of four! The failure comes from testTreasuresCannotBeStolen(). That doesn't sound good!

If we check that out... this is a interesting test: we ->patch() to update a $user, and then try to set the dragonTreasures property to a treasure that is owned by a different user. You can see that this $dragonTreasure is owned by $otherUser... but we're currently updating $user.

What we're attempting to do is steal this $dragonTreasure from $otherUser and make it part of $user. Dragons do not appreciate being robbed, so we're asserting that this is a 422 status code... because previously, we had a custom validator that prevented this.

Well, it still exists - it's this TreasuresAllowedOwnerChangeValidator - but it's not being applied to UserApi... and it needs to be updated to work with it. We'll do this later.

More importantly right now, the dragonTreasures property isn't even writable! In UserApi, above $dragonTreasures, we have writable: false. In a bit, we're going to change that so that we can write dragonTreasures again. And when we do, we'll bring back that validator and make sure this test passes.

Next: If you look at the processor or the provider we created, these classes are pretty generic. They could almost work for UserApi and a future DragonTreasureApi class... and any other DTO class we create that's tied to an entity. The only part that's specific to User is the code that maps to and from the User entity and the UserApi class.

If we could handle that mapping... in some system that lives outside our provider and processor... we could reuse them. Let's make this a reality next!