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How to use Expressions in Security, Routing, Services, and Validation

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How to use Expressions in Security, Routing, Services, and Validation

Symfony comes with a powerful ExpressionLanguage component. It allows you to add highly customized logic inside configuration.

The Symfony Framework leverages expressions out of the box in the following ways:

For more information about how to create and work with expressions, see The Expression Syntax.

Security: Complex Access Controls with Expressions

In addition to a role like ROLE_ADMIN, the isGranted() method also accepts an Symfony\Component\ExpressionLanguage\Expression object:

use Symfony\Component\ExpressionLanguage\Expression;
// ...

public function indexAction()
{
    $this->denyAccessUnlessGranted(new Expression(
        '"ROLE_ADMIN" in roles or (user and user.isSuperAdmin())'
    ));

    // ...
}

In this example, if the current user has ROLE_ADMIN or if the current user object’s isSuperAdmin() method returns true, then access will be granted (note: your User object may not have an isSuperAdmin() method, that method is invented for this example).

This uses an expression and you can learn more about the expression language syntax, see The Expression Syntax.

Inside the expression, you have access to a number of variables:

user
The user object (or the string anon if you’re not authenticated).
roles
The array of roles the user has, including from the role hierarchy but not including the IS_AUTHENTICATED_* attributes (see the functions below).
object
The object (if any) that’s passed as the second argument to isGranted().
token
The token object.
trust_resolver
The Symfony\Component\Security\Core\Authentication\AuthenticationTrustResolverInterface, object: you’ll probably use the is_*() functions below instead.

Additionally, you have access to a number of functions inside the expression:

is_authenticated
Returns true if the user is authenticated via “remember-me” or authenticated “fully” - i.e. returns true if the user is “logged in”.
is_anonymous
Equal to using IS_AUTHENTICATED_ANONYMOUSLY with the isGranted() function.
is_remember_me
Similar, but not equal to IS_AUTHENTICATED_REMEMBERED, see below.
is_fully_authenticated
Similar, but not equal to IS_AUTHENTICATED_FULLY, see below.
has_role
Checks to see if the user has the given role - equivalent to an expression like 'ROLE_ADMIN' in roles.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.