GraphQL Request Builder

This library builds a request for sending to a GraphQL server.

What is GraphQL?

GraphQL is a query language to easy request data from remote web servers. There are several pros for using GraphQL instead of REST like

• decreasing request amount
• saving traffic in payload
• avoid backend changes on changing client requested data

For a full description see How to GraphQL.

Naming conventions

The schema of GraphQL is defined by two easy attributes:

• Types
• Arguments

Type define a structured requested data object. Arguments can define these types.

Example

A type forum can have posts, which has authors and a title. If you want to receive all author ant post title information as response your request can look like this:

{
  forum {
    posts {
      authors,
      title
    }
  }
}

To specify your requested data for crawling only the last 5 posts you can modify your request like this:

{
  forum {
    posts(last: 5) {
      authors,
      title
    }
  }
}

GraphQL requested data can complex as you want:

{
  forum {
    posts(last: 5) {
      authors(registration: {date: "2019-08-08"}, visible: true) {
        surname,
        prename(startingWith: "a"),
        birthday
      },
      title
    },
    users(last: 10, sort: "registrationDate", order: "DESC")
  }
}

Why this library?

This library helps building this payload structure without any string concatenation or other strange ideas.

Example

To create following request payload

{
  field {
    search(criteria: {start: "2019-08-23"}) {
      errors {
        code
        type
        description
      }
      id
    }
  }
}

you need to execute following PHP code

<?php
declare(strict_types=1);

use GraphQL\RequestBuilder\Argument;
use GraphQL\RequestBuilder\RootType;
use GraphQL\RequestBuilder\Type;

$searchType = (new Type('search'))
    ->addArgument(new Argument('criteria', new Argument('start', '2019-08-23')))
    ->addSubTypes([
        (new Type('errors'))->addSubTypes(['code', 'type', 'description']),
        'id'
    ]
);

echo (string) (new RootType('field'))->addSubType($searchType);

Build complex types

Its also possible to build complex types. This code examples show you how to do this.

Arguments with array of arguments

Sometimes you want to have arrays with complex Argument types, like the following example.

{
  persons: [
    {age: 30},
    {age: 20},
    {age: 12}
  ]
}

For this concept you can use the class ArrayArgument which give the possibility to add Arguments to an array.

<?php
declare(strict_types=1);

use GraphQL\RequestBuilder\Argument;
use GraphQL\RequestBuilder\ArrayArgument;

$persons = new ArrayArgument(
    'persons',
    [new Argument('age', 30), new Argument('age', 20), new Argument('age', 12)]
);

Arrays with more than one Argument in value.

The example above works if you have an array with only one Argument: every person only has one Argument, the age. If you want to have more Arguments you need to create an Argumentwith an empty name.

{
  persons: [
    {
      name: "Hans",
      age: 30
    },
    {
      name: "Max",
      age: 20
    }
  ]
}

Your PHP code should look like this:

<?php
declare(strict_types=1);

use GraphQL\RequestBuilder\Argument;
use GraphQL\RequestBuilder\ArrayArgument;

$person1 = new ArrayArgument('', [new Argument('name', 'Hans'), new Argument('age', 30)]);
$person2 = new ArrayArgument('', [new Argument('name', 'Max'), new Argument('age', 20)]);

$persons = new ArrayArgument('persons', [$person1, $person2]);

Enum arguments

To create enum arguments it should look like this:

<?php
declare(strict_types=1);

use GraphQL\RequestBuilder\EnumArgument;

$person1 = new EnumArgument('EnumAttribute', 'EnumValue');