GraphQL in PHP: webonyx/graphql-php library for creating APIs

GraphQL PHP Library: webonyx/graphql-php

In modern web development, the need for flexible and efficient APIs is increasingly common. Traditional REST services often suffer from over-fetching or under-fetching of data. GraphQL is a query language and runtime environment created by Facebook that allows clients to request exactly the data they need. For PHP, one of the most popular implementations is the webonyx/graphql-php library.

This library provides a complete set of tools for building GraphQL servers in PHP: from defining a type schema to processing complex queries with nested relationships. It is ideal for creating modern APIs for web applications, mobile applications, and SPAs (Single Page Applications).

Key Features of webonyx/graphql-php

• Full support for the GraphQL specification (June 2018) — all types, directives, variables, and fragments.
• Type system based on PHP objects — defining types, interfaces, union types, and enums.
• Built-in resolvers — the ability to define data retrieval logic for each field.
• Query validation — automatic syntax and type checking.
• Lazy loading support — data is loaded only on demand.
• Compatibility with popular frameworks — Laravel, Symfony, Yii2 via wrapper packages.

Installation and Setup

Installation is done via Composer:

composer require webonyx/graphql-php

PHP 7.1+ with the mbstring extension is required. After installation, let's create a simple server.

Example: Creating a GraphQL Schema

Let's look at a basic example — fetching a list of books and authors. First, define the types:

<?phpuse GraphQL\\Type\\Definition\\ObjectType;use GraphQL\\Type\\Definition\\Type;use GraphQL\\Type\\Schema;

// Type "Author"$authorType = new ObjectType([    'name' => 'Author',    'fields' => [        'id' => Type::int(),        'name' => Type::string(),        'books' => [            'type' => Type::listOf($bookType), // will be defined below            'resolve' => function ($author) {                // Assume there is a function getBooksByAuthorId()                return getBooksByAuthorId($author['id']);            }        ]    ]]);

// Type "Book" (defined with a closure for circular references)$bookType = new ObjectType([    'name' => 'Book',    'fields' => function() use ($authorType) {        return [            'id' => Type::int(),            'title' => Type::string(),            'author' => [                'type' => $authorType,                'resolve' => function ($book) {                    return getAuthorById($book['author_id']);                }            ]        ];    }]);

// Type "Query"$queryType = new ObjectType([    'name' => 'Query',    'fields' => [        'books' => [            'type' => Type::listOf($bookType),            'resolve' => function() {                return getAllBooks();            }        ],        'author' => [            'type' => $authorType,            'args' => [                'id' => Type::nonNull(Type::int())            ],            'resolve' => function($root, $args) {                return getAuthorById($args['id']);            }        ]    ]]);

// Create the schema$schema = new Schema([    'query' => $queryType]);

Handling a Query

Now let's write the code that accepts a GraphQL query and returns the result:

<?phpuse GraphQL\\GraphQL;use GraphQL\\Error\\DebugFlag;

// Get the request body from the in