GraphQL Language

![Software License][ico-license] ![Coverage Status][ico-scrutinizer] ![Total Downloads][ico-downloads], _(*1)

A GraphQL parser written in PHP. The parser is able to parse the full spec. This package is compatible with PHP 5.3+. I'm still actively working on this project. Expect things to break. 🙈, _(*2)

This package is being developed together with a server package, which isn't public yet., _(*3)

Install

Via Composer, _(*4)

``` bash $ composer require hansott/graphql-language, _(*5)


## Usage

### Parsing a query to a [HansOtt\GraphQL\Query\Document](src/Query/Document.php)

``` php
use HansOtt\GraphQL\Query\ParseError;
use HansOtt\GraphQL\Query\SyntaxError;
use HansOtt\GraphQL\Query\ParserFactory;

$factory = new ParserFactory;
$parser = $factory->create();

$query = <<<'QUERY'
    {
        author(id: 1) {
            name
        }
    }
QUERY;

try {
    $document = $parser->parse($query);
    var_dump($document); // Instance of HansOtt\GraphQL\Query\Document
} catch (SyntaxError $e) {
    echo "Syntax error in query: {$e->getMessage()}" . PHP_EOL;
} catch (ParseError $e) {
    echo "Failed to parse query: {$e->getMessage()}" . PHP_EOL;
}

Traversing a HansOtt\GraphQL\Query\Document

use HansOtt\GraphQL\Query\Node;
use HansOtt\GraphQL\Query\Traverser;
use HansOtt\GraphQL\Query\VisitorBase;
use HansOtt\GraphQL\Query\OperationQuery;

final class VisitorQueryFinder extends VisitorBase // Or implement HansOtt\GraphQL\Query\Visitor
{
    /**
     * @var OperationQuery[]
     */
    private $queries = [];

    public function enterNode(Node $node)
    {
        if ($node instanceof OperationQuery) {
            $this->queries[] = $node;
        }
    }

    public function getQueries()
    {
        return $this->queries;
    }
}

$document = $parser->parse($query);
$finder = new VisitorQueryFinder;

$traverser = new Traverser($finder);
$traverser->traverse($document);
var_dump($finder->getQueries());

// Or if you need multiple visitors
// use HansOtt\GraphQL\Query\VisitorMany

$visitors = new VisitorMany([$finder, ...]);
$traverser = new Traverser($visitors);
$traverser->traverse($document);
var_dump($finder->getQueries());

Parsing a schema declaration to a HansOtt\GraphQL\Schema\Schema

use HansOtt\GraphQL\Schema\ParseError;
use HansOtt\GraphQL\Schema\SyntaxError;
use HansOtt\GraphQL\Schema\ParserFactory;

$factory = new ParserFactory;
$parser = $factory->create();

$schema = <<<'SCHEMA'
    enum DogCommand { SIT, DOWN, HEEL }

    type Dog implements Pet {
        name: String!
        nickname: String
        barkVolume: Int
        doesKnowCommand(dogCommand: DogCommand!): Boolean!
        isHousetrained(atOtherHomes: Boolean): Boolean!
        owner: Human
    }

    interface Sentient {
        name: String!
    }

    interface Pet {
        name: String!
    }

    type Alien implements Sentient {
        name: String!
        homePlanet: String
    }

    type Human implements Sentient {
        name: String!
    }

    enum CatCommand { JUMP }

    type Cat implements Pet {
        name: String!
        nickname: String
        doesKnowCommand(catCommand: CatCommand!): Boolean!
        meowVolume: Int
    }

    union CatOrDog = Cat | Dog
    union DogOrHuman = Dog | Human
    union HumanOrAlien = Human | Alien

    type QueryRoot {
        dog: Dog
    }
SCHEMA;

try {
    $schema = $parser->parse($schema);
    var_dump($schema); // Instance of HansOtt\GraphQL\Schema\Schema
} catch (SyntaxError $e) {
    echo "Syntax error in query: {$e->getMessage()}" . PHP_EOL;
} catch (ParseError $e) {
    echo "Failed to parse query: {$e->getMessage()}" . PHP_EOL;
}