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https://github.com/digiaonline/graphql-php
A PHP7 implementation of the GraphQL specification.
https://github.com/digiaonline/graphql-php
api graphql php php-library php7
Last synced: about 1 month ago
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A PHP7 implementation of the GraphQL specification.
- Host: GitHub
- URL: https://github.com/digiaonline/graphql-php
- Owner: digiaonline
- License: mit
- Archived: true
- Created: 2018-02-07T14:37:21.000Z (almost 7 years ago)
- Default Branch: main
- Last Pushed: 2022-05-04T10:49:18.000Z (over 2 years ago)
- Last Synced: 2024-05-22T19:28:56.443Z (7 months ago)
- Topics: api, graphql, php, php-library, php7
- Language: PHP
- Homepage: https://facebook.github.io/graphql/
- Size: 1.65 MB
- Stars: 217
- Watchers: 21
- Forks: 11
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: .github/CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
Awesome Lists containing this project
- awesome-graphql - digiaonline - Yet another PHP port of GraphQL reference implementation. (Libraries / PHP Libraries)
- awesome-graphql - digiaonline - Yet another PHP port of GraphQL reference implementation. (Libraries / PHP Libraries)
README
# GraphQL
[](https://github.com/digiaonline/graphql-php/actions)
[](https://coveralls.io/github/digiaonline/graphql-php?branch=main)
[](https://scrutinizer-ci.com/g/digiaonline/graphql-php/?branch=main)
[](https://raw.githubusercontent.com/digiaonline/graphql-php/main/LICENSE)
[](#backers)
[](#sponsors)
This is a PHP implementation of the [GraphQL specification](https://facebook.github.io/graphql/) based on the
JavaScript [reference implementation](https://github.com/graphql/graphql-js).
## Related projects
- [DateTime scalar](https://github.com/digiaonline/graphql-datetime-scalar-php)
- [Relay support](https://github.com/digiaonline/graphql-relay-php)
## Requirements
- PHP version >= 7.1
- ext-mbstring
## Table of contents
- [Installation](#installation)
- [Example](#example)
- [Creating a schema](#creating-a-schema)
- [Resolver registry](#resolver-registry)
- [Resolver middleware](#resolver-middleware)
- [Execution](#execution)
- [Queries](#queries)
- [Resolvers](#resolvers)
- [The N+1 problem](#the-n1-problem)
- [Variables](#variables)
- [Context](#context)
- [Scalars](#scalars)
- [Custom scalars](#custom-scalars)
- [Advanced usage](#advanced-usage)
- [Integration](#integration)
- [Laravel](#laravel)
## Installation
Run the following command to install the package through Composer:
```sh
composer require digiaonline/graphql
```
## Example
Here is a simple example that demonstrates how to build an executable schema from a GraphQL schema file that contains
the Schema Definition Language (SDL) for a Star Wars-themed schema (for the schema definition itself, see below). In
this example we use that SDL to build an executable schema and use it to query for the name of the hero. The result
of that query is an associative array with a structure that resembles the query we ran.
```php
use Digia\GraphQL\Language\FileSourceBuilder;
use function Digia\GraphQL\buildSchema;
use function Digia\GraphQL\graphql;
$sourceBuilder = new FileSourceBuilder(__DIR__ . '/star-wars.graphqls');
$schema = buildSchema($sourceBuilder->build(), [
'Query' => [
'hero' => function ($rootValue, $arguments) {
return getHero($arguments['episode'] ?? null);
},
],
]);
$result = graphql($schema, '
query HeroNameQuery {
hero {
name
}
}');
\print_r($result);
```
The script above produces the following output:
```php
Array
(
[data] => Array
(
[hero] => Array
(
[name] => "R2-D2"
)
)
)
```
The GraphQL schema file used in this example contains the following:
```graphql schema
schema {
query: Query
}
type Query {
hero(episode: Episode): Character
human(id: String!): Human
droid(id: String!): Droid
}
interface Character {
id: String!
name: String
friends: [Character]
appearsIn: [Episode]
}
type Human implements Character {
id: String!
name: String
friends: [Character]
appearsIn: [Episode]
homePlanet: String
}
type Droid implements Character {
id: String!
name: String
friends: [Character]
appearsIn: [Episode]
primaryFunction: String
}
enum Episode { NEWHOPE, EMPIRE, JEDI }
```
## Creating a schema
In order to execute queries against your GraphQL API, you first need to define the structure of your API. This is done
by creating a schema. There are two ways to do this, you can either do it using SDL or you can do it programmatically.
However, we strongly encourage you to use SDL, because it is easier to work with. To make an executable schema from
SDL you need to call the `buildSchema` function.
The `buildSchema` function takes three arguments:
- `$source` The schema definition (SDL) as a `Source` instance
- `$resolverRegistry` An associative array or a `ResolverRegistry` instance that contains all resolvers
- `$options` The options for building the schema, which also includes custom types and directives
To create the `Source` instance you can use the provided `FileSourceBuilder` or `MultiFileSourceBuilder` classes.
### Resolver registry
The resolver registry is essentially a flat map with the type names as its keys and their corresponding resolver
instances as its values. For smaller projects you can use an associative array and lambda functions to define your
resolver registry. However, in larger projects we suggest that you implement your own resolvers instead. You can read
more about resolvers under the [Resolvers](#resolvers) section.
Associative array example:
```php
$schema = buildSchema($source, [
'Query' => [
'hero' => function ($rootValue, $arguments) {
return getHero($arguments['episode'] ?? null);
},
],
]);
```
Resolver class example:
```php
$schema = buildSchema($source, [
'Query' => [
'hero' => new HeroResolver(),
],
]);
```
### Resolver middleware
If you find yourself writing the same logic in multiple resolvers you should consider using middleware. Resolver
middleware allow you to efficiently manage functionality across multiple resolvers.
Before middleware example:
```php
$resolverRegistry = new ResolverRegristry([
'Query' => [
'hero' => function ($rootValue, $arguments) {
return getHero($arguments['episode'] ?? null);
},
],
], [
'middleware' => [new BeforeMiddleware()],
]);
$schema = buildSchema($source, $resolverRegistry);
```
```php
class BeforeMiddleware implements ResolverMiddlewareInterface
{
public function resolve(callable $resolveCallback, $rootValue, array $arguments, $context, ResolveInfo $info) {
$newRootValue = $this->doSomethingBefore();
return $resolveCallback($newRootValue, $arguments, $context, $info);
}
}
```
After middleware example:
```php
$resolverRegistry = new ResolverRegristry([
'Query' => [
'hero' => function ($rootValue, $arguments) {
return getHero($arguments['episode'] ?? null);
},
],
], [
'middleware' => [new AfterMiddleware()],
]);
$schema = buildSchema($source, $resolverRegistry);
```
```php
class AfterMiddleware implements ResolverMiddlewareInterface
{
public function resolve(callable $resolveCallback, $rootValue, array $arguments, $context, ResolveInfo $info) {
$result = $resolveCallback($rootValue, $arguments, $context, $info);
$this->doSomethingAfter();
return $result;
}
}
```
Resolver middleware can be useful for a number of things; such as logging, input sanitization, performance
measurement, authorization and caching.
If you want to learn more about schemas you can refer to the [specification](https://graphql.org/learn/schema/).
## Execution
### Queries
To execute a query against your schema you need to call the `graphql` function and pass it your schema and the query
you wish to execute. You can also run _mutations_ and _subscriptions_ by changing your query.
```php
$query = '
query HeroNameQuery {
hero {
name
}
}';
$result = graphql($schema, $query);
```
If you want to learn more about queries you can refer to the [specification](https://graphql.org/learn/queries/).
### Resolvers
Each type in a schema has a resolver associated with it that allows for resolving the actual value. However, most
types do not need a custom resolver, because they can be resolved using the default resolver. Usually these resolvers
are lambda functions, but you can also define your own resolvers by extending `AbstractTypeResolver` or `AbstractFieldResolver`. Alternatively you can also implement the `ResolverInterface` directly.
A resolver function receives four arguments:
- `$rootValue` The parent object, which can also be `null` in some cases
- `$arguments` The arguments provided to the field in the query
- `$context` A value that is passed to every resolver that can hold important contextual information
- `$info` A value which holds field-specific information relevant to the current query
Lambda function example:
```php
function ($rootValue, array $arguments, $context, ResolveInfo $info): string {
return [
'type' => 'Human',
'id' => '1000',
'name' => 'Luke Skywalker',
'friends' => ['1002', '1003', '2000', '2001'],
'appearsIn' => ['NEWHOPE', 'EMPIRE', 'JEDI'],
'homePlanet' => 'Tatooine',
];
}
```
Type resolver example:
```php
class HumanResolver extends AbstractTypeResolver
{
public function resolveName($rootValue, array $arguments, $context, ResolveInfo $info): string
{
return $rootValue['name'];
}
}
```
Field resolver example:
```php
class NameResolver extends AbstractFieldResolver
{
public function resolve($rootValue, array $arguments, $context, ResolveInfo $info): string
{
return $rootValue['name'];
}
}
```
#### The N+1 problem
The resolver function can return a value, a [promise](https://github.com/reactphp/promise) or an array of promises.
This resolver function below illustrates how to use promise to solve the N+1 problem, the full example can be found in
this [test case](/tests/Functional/Execution/DeferredResolverTest.php).
```php
$movieType = newObjectType([
'fields' => [
'title' => ['type' => stringType()],
'director' => [
'type' => $directorType,
'resolve' => function ($movie, $args) {
DirectorBuffer::add($movie['directorId']);
return new Promise(function (callable $resolve, callable $reject) use ($movie) {
DirectorBuffer::loadBuffered();
$resolve(DirectorBuffer::get($movie['directorId']));
});
}
]
]
]);
```
### Variables
You can pass in variables when executing a query by passing them to the `graphql` function.
```php
$query = '
query HeroNameQuery($id: ID!) {
hero(id: $id) {
name
}
}';
$variables = ['id' => '1000'];
$result = graphql($schema, $query, null, null, $variables);
```
### Context
In case you need to pass in some important contextual information to your queries you can use the `$contextValues`
argument on `graphql` to do so. This data will be passed to all of your resolvers as the `$context` argument.
```php
$contextValues = [
'currentlyLoggedInUser' => $currentlyLoggedInUser,
];
$result = graphql($schema, $query, null, $contextValues, $variables);
```
## Scalars
The leaf nodes in a schema are called scalars and each scalar resolves to some concrete data. The built-in, or
specified scalars in GraphQL are the following:
- Boolean
- Float
- Int
- ID
- String
### Custom scalars
In addition to the specified scalars you can also define your own custom scalars and let your schema know about
them by passing them to the `buildSchema` function as part of its `$options` argument.
Custom Date scalar type example:
```php
$dateType = newScalarType([
'name' => 'Date',
'serialize' => function ($value) {
if ($value instanceof DateTime) {
return $value->format('Y-m-d');
}
return null;
},
'parseValue' => function ($value) {
if (\is_string($value)){
return new DateTime($value);
}
return null;
},
'parseLiteral' => function ($node) {
if ($node instanceof StringValueNode) {
return new DateTime($node->getValue());
}
return null;
},
]);
$schema = buildSchema($source, [
'Query' => QueryResolver::class,
[
'types' => [$dateType],
],
]);
```
Every scalar has to be coerced, which is done by three different functions. The `serialize` function converts a
PHP value into the corresponding output value. The`parseValue` function converts a variable input value into the
corresponding PHP value and the `parseLiteral` function converts an AST literal into the corresponding PHP value.
## Advanced usage
If you are looking for something that isn't yet covered by this documentation your best bet is to take a look at the
[tests](./tests) in this project. You'll be surprised how many examples you'll find there.
## Integration
### Laravel
Here is an example that demonstrates how you can use this library in your Laravel project. You need an application
service to expose this library to your application, a service provider to register that service, a controller and a
route for handling the GraphQL POST requests.
**app/GraphQL/GraphQLService.php**
```php
class GraphQLService
{
private $schema;
public function __construct(Schema $schema)
{
$this->schema = $schema;
}
public function executeQuery(string $query, array $variables, ?string $operationName): array
{
return graphql($this->schema, $query, null, null, $variables, $operationName);
}
}
```
**app/GraphQL/GraphQLServiceProvider.php**
```php
class GraphQLServiceProvider
{
public function register()
{
$this->app->singleton(GraphQLService::class, function () {
$schemaDef = \file_get_contents(__DIR__ . '/schema.graphqls');
$executableSchema = buildSchema($schemaDef, [
'Query' => QueryResolver::class,
]);
return new GraphQLService($executableSchema);
});
}
}
```
**app/GraphQL/GraphQLController.php**
```php
class GraphQLController extends Controller
{
private $graphqlService;
public function __construct(GraphQLService $graphqlService)
{
$this->graphqlService = $graphqlService;
}
public function handle(Request $request): JsonResponse
{
$query = $request->get('query');
$variables = $request->get('variables') ?? [];
$operationName = $request->get('operationName');
$result = $this->graphqlService->executeQuery($query, $variables, $operationName);
return response()->json($result);
}
}
```
**routes/api.php**
```php
Route::post('/graphql', 'app\GraphQL\GraphQLController@handle');
```
## Contributors
This project exists thanks to all the people who contribute. [Contribute](.github/CONTRIBUTING.md).
## Backers
Thank you to all our backers! 🙏 [Become a backer](https://opencollective.com/graphql-php#backer)
## Sponsors
Support this project by becoming a sponsor. Your logo will show up here with a link to your website. [Become a sponsor](https://opencollective.com/graphql-php#sponsor)
## License
See [LICENCE](LICENSE).