All definition config entries can use expression language but it must be explicitly triggered using "@=" like prefix.
Functions description:
| Expression | Description | Usage | Alias |
|---|---|---|---|
| object service(string $id) | Get a service from the container | @=service('my_service').customMethod() | serv |
| mixed parameter(string $name) | Get parameter from the container | @=parameter('kernel.debug') | param |
| boolean isTypeOf(string $className) | Verified if value is instance of className |
@=isTypeOf('AppBundle\User\User') | |
| mixed resolver(string $alias, array $args = []) | call the method on the tagged service "overblog_graphql.resolver" with args | @=resolver('blog_by_id', [value['blogID']] | res |
| mixed mutation(string $alias, array $args = []) | call the method on the tagged service "overblog_graphql.mutation" with args | @=mutation('remove_post_from_community', [value]) | mut |
| mixed input(string $type, mixed $data) | Transform and validate an input using the Input Builder service. (see The Input Builder ) |
@=service('my_service').method(input(value)) | |
| string globalId(string|int id, string $typeName = null) | Relay node globalId | @=globalId(15, 'User') | |
| array fromGlobalId(string $globalId) | Relay node fromGlobalId | @=fromGlobalId('QmxvZzox') | |
| object newObject(string $className, array $args = []) | Instantiation $className object with $args | @=newObject('AppBundle\User\User', ['John', 15]) | |
| boolean hasRole(string $role) | Checks whether the token has a certain role. | @=hasRole('ROLE_API') | |
| boolean hasAnyRole(string $role1, string $role2, ...string $roleN) | Checks whether the token has any of the given roles. | @=hasAnyRole('ROLE_API', 'ROLE_ADMIN') | |
| boolean isAnonymous() | Checks whether the token is anonymous. | @=isAnonymous() | |
| boolean isRememberMe() | Checks whether the token is remember me. | @=isRememberMe() | |
| boolean isFullyAuthenticated() | Checks whether the token is fully authenticated. | @=isFullyAuthenticated() | |
| boolean isAuthenticated() | Checks whether the token is not anonymous. | @=isAuthenticated() | |
| boolean hasPermission(mixed $var, string $permission) | Checks whether the token has the given permission for the given object (requires the ACL system). | @=hasPermission(object, 'OWNER') | |
| boolean hasAnyPermission(mixed $var, array $permissions) | Checks whether the token has any of the given permissions for the given object | @=hasAnyPermission(object, ['OWNER', 'ADMIN']) | |
| User getUser() | Returns the user which is currently in the security token storage. User can be null. | @=getUser() |
Variables description:
| Expression | Description | Scope |
|---|---|---|
| typeResolver | the type resolver | global |
| object | Refers to the value of the field for which access is being requested. For array object will be each item of the array. For Relay connection object will be the node of each connection edges. |
only available for config.fields.*.access with query operation or mutation payload type. |
| value | Resolver value | only available in resolve context |
| args | Resolver args array | only available in resolve context |
| info | Resolver GraphQL\Type\Definition\ResolveInfo Object | only available in resolve context |
| context | context is defined by your application on the top level of query execution (useful for storing current user, environment details, etc) | only available in resolve context |
| childrenComplexity | Selection field children complexity | only available in complexity context |
For more details on expression syntax
Adding custom expression function is easy since all you need to do is create a tagged service. Expression functions can help user create simple resolver without having to leave config file, this also improves performance by removing a useless external resolver call.
Here is an example to add a custom expression equivalent to php json_decode:
<?php
namespace App\ExpressionLanguage;
use Overblog\GraphQLBundle\ExpressionLanguage\ExpressionFunction;
class JsonDecode extends ExpressionFunction
{
public function __construct()
{
parent::__construct(
'json_encode',
function ($json, $assoc) {
return sprintf('json_decode(%s, %s)', $json, $assoc);
}
);
}
}now register your service
App\ExpressionLanguage\JsonDecode:
tags: ['overblog_graphql.expression_function']Now json_decode can be used in schema:
Object:
type: object
config:
fields:
name:
type: String!
resolve: "@=json_decode(value.json_data, true)['name']"Tips: At last if this is not an answer to all your needs, the expression language service can be customized using bundle configuration.