description: >- On the previous guide you saw how to map resolvers (callables) from a existing SDL (.graphql or .gql). Annotations enables the other way around, it provides a GraphQL SDL from annotated PHP code.

@Annotations

Thank you Doctrine

Siler's GraphQL Annotations uses the super-powers from Doctrine's Annotations and like any other dependency, is a peer that we should explicitly require:

$ composer require doctrine/annotations

What is available:

There are 9 annotations fulfilling the GraphQL's ecosystem:

Class annotations are:

• ObjectType
• InterfaceType
• InputType
• EnumType
• UnionType
• Directive

Complementary method and property annotations are:

• Field
• Args
• EnumVal

They follow a ubiquitous language to GraphQL spec, so if you know GraphQL, there is nothing new here, you probably already know what each of them does just by its name.

Hello, World!

Let's start by defining our root query:

<?php declare(strict_types=1);

namespace App;

use GraphQL\Type\Definition\ResolveInfo;
use Siler\GraphQL\Annotation\Field;
use Siler\GraphQL\Annotation\ObjectType;

/** [@ObjectType](https://github.com/ObjectType) */
class Query
{
    /** [@Field](https://github.com/Field)(description="A common greet") */
    public static function hello(): string
    {
        return 'Hello, World!';
    }
}

The ObjectType name will be inferred by the class name, so it will already be Query.

Then we just provide this class to the annotated function on the Siler\GraphQL namespace:

<?php declare(strict_types=1);

namespace App;

use function Siler\GraphQL\{annotated, init};

require_once __DIR__ . '/vendor/autoload.php';

$schema = annotated([Query::class]);
init($schema);

And that is it! It auto-magically servers the following SDL:

type Query {
  """
  A common greet
  """
  hello: String!
}

With the static hello method body already playing the resolver role, so:

query {
  hello
}

Returns:

{
  "data": {
    "hello": "Hello, World!"
  }
}

For a full-featured example, please take a look at: github.com/leocavalcante/siler/examples/graphql-annotations****

Caching

Parsing docblocks can be expensive, on production environments is recommended to cache this process by using a caching reader.

First, install doctrine/cache:

composer require doctrine/cache

Then pass a Doctrine\Common\Cache\Cache to Siler\GraphQL\Deannotator::cache() like:

Siler\GraphQL\Deannotator::cache(new ApcuCache());

{% hint style="info" %} Make sure you do this before the annotated() call. {% endhint %}