Security

The API Platform security layer is built on top of the Symfony Security component. All its features, including global access control directives are supported. API Platform also provides convenient access control expressions which you can apply at resource and operation level.

Watch the Security screencast

```yaml
# api/config/api_platform/resources.yaml
App\Entity\Book:
    attributes:
        security: 'is_granted("ROLE_USER")'
    collectionOperations:
        get: ~
        post:
            security: 'is_granted("ROLE_ADMIN")'
    itemOperations:
        get: ~
        put:
            security: 'is_granted("ROLE_ADMIN") or object.owner == user'

In this example:

• The user must be logged in to interact with Book resources (configured at the resource level)
• Only users having the role ROLE_ADMIN can create a new resource (configured on the post operation)
• Only users having the ROLE_ADMIN or owning the current object can replace an existing book (configured on the put operation)

Available variables are user (the current logged in object, if any), and object (the current resource, or collection of resources for collection operations).

Access control checks in the security attribute are always executed before the denormalization step. It means than for PUT requests, object doesn’t contain the value submitted by the user, but values currently stored in the persistence layer.

In some cases, it might be useful to execute a security after the denormalization step. To do so, use the security_post_denormalize attribute:

```yaml
# api/config/api_platform/resources.yaml
App\Entity\Book:
    itemOperations:
        get: ~
        put:
            security_post_denormalize: "is_granted('ROLE_ADMIN') or (object.owner == user and previous_object.owner == user)"
    # ...

This time, the object variable contains data that have been extracted from the HTTP request body during the denormalization process. However, the object is not persisted yet.

Additionally, in some cases you need to perform security checks on the original data. For example here, only the actual owner should be allowed to edit their book. In these cases, you can use the previous_object variable which contains the object that was read from the data provider.

The value in the previous_object variable is cloned from the original object. Note that, by default, this clone is not a deep one (it doesn’t clone relationships, relationships are references). To make a deep clone, implement __clone method in the concerned resource class.

The easiest and recommended way to hook custom access control logic is to write Symfony Voter classes. Your custom voters will automatically be used in security expressions through the is_granted() function.

In order to give the current object to your voter, use the expression is_granted('READ', object)

For example:

<?php
// api/src/Entity/Book.php

namespace App\Entity;

use ApiPlatform\Core\Annotation\ApiResource;

/**
 * ...
 * @ApiResource(
 *     attributes={"security"="is_granted('ROLE_USER')"},
 *     collectionOperations={
 *          "get",
 *          "post" = { "security_post_denormalize" = "is_granted('BOOK_CREATE', object)" }
 *     },
 *     itemOperations={
 *          "get" = { "security" = "is_granted('BOOK_READ', object)" },
 *          "put" = { "security" = "is_granted('BOOK_EDIT', object)" },
 *          "delete" = { "security" = "is_granted('BOOK_DELETE', object)" }
 *     },
 * )
 */
class Book
{
    // ...
}

Please note that if you use both attributes={"security"=".. and then "post" = { "security_post_denormalize" = "..., the security on top level is called first, and after security_post_denormalize. This could lead to unwanted behaviour, so avoid using both of them simultaneously. If you need to use security_post_denormalize, consider adding security for the other operations instead of the global one.

Create a BookVoter with the bin/console make:voter command:

<?php
// api/src/Security/Voter/BookVoter.php

namespace App\Security\Voter;

use App\Entity\Book;
use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
use Symfony\Component\Security\Core\Authorization\Voter\Voter;
use Symfony\Component\Security\Core\Security;
use Symfony\Component\Security\Core\User\UserInterface;

class BookVoter extends Voter
{
    private $security = null;

    public function __construct(Security $security)
    {
        $this->security = $security;
    }

    protected function supports($attribute, $subject): bool
    {
        $supportsAttribute = in_array($attribute, ['BOOK_CREATE', 'BOOK_READ', 'BOOK_EDIT', 'BOOK_DELETE']);
        $supportsSubject = $subject instanceof Book;

        return $supportsAttribute && $supportsSubject;
    }

    /**
     * @param string $attribute
     * @param Book $subject
     * @param TokenInterface $token
     * @return bool
     */
    protected function voteOnAttribute($attribute, $subject, TokenInterface $token): bool
    {
        /** ... check if the user is anonymous ... **/

        switch ($attribute) {
            case 'BOOK_CREATE':
                if ( $this->security->isGranted(Role::ADMIN) ) { return true; }  // only admins can create books
                break;
            case 'BOOK_READ':
                /** ... other autorization rules ... **/
        }

        return false;
    }
}

Note 1: When using Voters on POST methods: The voter needs an $attribute and $subject as input parameter, so you have to use the security_post_denormalize (i.e. "post" = { "security_post_denormalize" = "is_granted('BOOK_CREATE', object)" } ) because the object does not exist before denormalization (it is not created, yet.)

Note 2: You can’t use Voters on the collection GET method, use Collection Filters instead.

By default when API requests are denied, you will get the “Access Denied” message. You can change it by configuring the security_message attribute or the security_post_denormalize_message attribute.

For example:

```yaml
# api/config/api_platform/resources.yaml
App\Entity\Book:
    attributes:
        security: 'is_granted("ROLE_USER")'
    collectionOperations:
        post:
            method: 'POST'
            security: 'is_granted("ROLE_ADMIN")'
            security_message: 'Only admins can add books.'
    itemOperations:
        get:
            method: 'GET'
            security: 'is_granted("ROLE_USER") and object.owner == user'
            security_message: 'Sorry, but you are not the book owner.'
        put:
            method: 'PUT'
            security_post_denormalize: "is_granted('ROLE_ADMIN') or (object.owner == user and previous_object.owner == user)"
            security_post_denormalize_message: 'Sorry, but you are not the actual book owner.'
    # ...

Filtering collections according to the role or permissions of the current user must be done directly at the data provider level. For instance, when using the built-in adapters for Doctrine ORM, MongoDB and ElasticSearch, removing entries from a collection should be done using extensions. Extensions allow to customize the generated DQL/Mongo/Elastic/… query used to retrieve the collection (e.g. add WHERE clauses depending of the currently connected user) instead of using access control expressions. As extensions are services, you can inject the Symfony Security class into them to access to current user’s roles and permissions.

If you use custom data providers, you’ll have to implement the filtering logic according to the persistence layer you rely on.

To completely disable some operations from your application, refer to the disabling operations section.

See how to dynamically change the current Serializer context according to the current logged in user.