Schema Definition Language

Since 0.9.0

The schema definition language is a convenient way to define your schema, especially with IDE autocompletion and syntax validation.

You can define this separate from your PHP code, e.g. in a schema.graphql file:

schema {
  query: Query
  mutation: Mutation
}

type Query {
  greetings(input: HelloInput!): String!
}

input HelloInput {
  firstName: String!
  lastName: String
}

In order to create schema instance out of this file, use GraphQL\Utils\BuildSchema:

use GraphQL\Utils\BuildSchema;

$contents = file_get_contents('schema.graphql');
$schema = BuildSchema::build($contents);

By default, such schema is created without any resolvers.

We have to rely on default field resolver and root value in order to execute a query against this schema.

Defining resolvers

Since 0.10.0

In order to enable Interfaces, Unions and custom field resolvers you can pass the second argument: type config decorator to schema builder.

It accepts default type config produced by the builder and is expected to add missing options like resolveType for interface types or resolveField for object types.

use GraphQL\Utils\BuildSchema;
use GraphQL\Language\AST\TypeDefinitionNode;

$typeConfigDecorator = function (array $typeConfig, TypeDefinitionNode $typeDefinitionNode): array {
    $name = $typeConfig['name'];
    // ... add missing options to $typeConfig based on type $name
    return $typeConfig;
};

$contents = file_get_contents('schema.graphql');
$schema = BuildSchema::build($contents, $typeConfigDecorator);

Performance considerations

Since 0.10.0

Method build() produces a lazy schema automatically, so it works efficiently even with very large schemas.

But parsing type definition file on each request is suboptimal, so it is recommended to cache intermediate parsed representation of the schema for the production environment:

use GraphQL\Language\Parser;
use GraphQL\Utils\BuildSchema;
use GraphQL\Utils\AST;

$cacheFilename = 'cached_schema.php';

if (!file_exists($cacheFilename)) {
    $document = Parser::parse(file_get_contents('./schema.graphql'));
    file_put_contents($cacheFilename, "<?php\nreturn " . var_export(AST::toArray($document), true) . ";\n");
} else {
    $document = AST::fromArray(require $cacheFilename); // fromArray() is a lazy operation as well
}

$typeConfigDecorator = function () {};
$schema = BuildSchema::build($document, $typeConfigDecorator);