API Transformer

Purpose

This library provides the core functionality for API transformation and is a base library for many other packages.

By itself it's not usable at all. Check the projects using it below.

Used by

Currently the following transformers make use of this library as foundation:

• nilportugues/json
• nilportugues/jsend
• nilportugues/hal
• nilportugues/json-api

Installation

Use Composer to install the package:

$ composer require nilportugues/api-transformer

How it works

Loading must be done using the Mapper class, as it expects an array containing a defined structure, or a class name implementing ApiMapping.

There are 2 styles for flexibility when integrating the library into PHP frameworks.

While I discourage having 2 styles for mapping it is well possible to have them side by side in the very same configuration file. The Mapper class that loads all Mappings does internal transformation for both, so client does not have to worry.

Usage

use NilPortugues\Api\Mapping\Mapper;
use NilPortugues\AcmeProject\Infrastructure\Api\Mappings\PostApiMapping;

$arrayConfig = include 'mappings.php';
$classConfig = [
	PostApiMapping::class,
];

$mappings = array_merge($classConfig, $arrayConfig);

//Now $mapper can be passed to a Transformer.
$mapper = new Mapper($mappings);

Creating the Mapping files

Implementing ApiMapping (Prefered method)

To create a Mapping you may implement the following interfaces:

• ApiMapping: transform your data into plain JSON for API consumtion or the JSend API format.
• JsonApiMapping to transform your data into the JSONAPI 1.0 standard.
• HalMapping to transform your data to HAL+JSON and HAL+XML API standards.

As expected you may implement many interfaces to support multiple API formats.

<?php

namespace NilPortugues\AcmeProject\Infrastructure\Api\Mappings;

use NilPortugues\AcmeProject\Blog\Domain\Post;
use NilPortugues\Api\Mappings\HalMapping;
use NilPortugues\Api\Mappings\JsonApiMapping;

class PostApiMapping implements JsonApiMapping, HalMapping
{
    /**
     * {@inheritdoc}
     */
    public function getClass() : string
    {
        return Post::class;
    }

    /**
     * {@inheritdoc}
     */
    public function getAlias() : string
    {
        return 'Posting'; //If none is used 'Post' will be used instead.
    }

    /**
     * {@inheritdoc}
     */
    public function getAliasedProperties() : array
    {
        return [
            'title' => 'headline',
            'content' => 'body',
        ];
    }

    /**
     * {@inheritdoc}
     */
    public function getHideProperties() : array
    {
        return [
           'comments',
       ];
    }

    /**
     * {@inheritdoc}
     */
    public function getIdProperties() : array
    {
        return [
            'postId',
        ];
    }

    /**
     * {@inheritdoc}
     */
    public function getUrls() : array
    {
        return [
          // Mandatory
          'self' => 'http://example.com/posts/{postId}',
          // Optional
          'comments' => 'http://example.com/posts/{postId}/comments',
        ];
    }

    /**
     * Returns an array of curies.
     *
     * @return array
     */
    public function getCuries() : array
    {
        return [
            'name' => 'example',
            'href' => 'http://example.com/docs/rels/{rel}',
        ];
    }

    /**
     * {@inheritdoc}
     */
    public function getRelationships() : array
    {
        return [
            'author' => [
                'related' => 'http://example.com/posts/{postId}/author',
                'self' => 'http://example.com/posts/{postId}/relationships/author',
            ],
        ];
    }
}

Mapping using an array

// mappings.php

return  [
  [
      'class' => Post::class,
      'alias' => 'Posting', //If none is used 'Post' will be used instead.
      'aliased_properties' => [
          'title' => 'headline',
          'content' => 'body',
      ],
      'hide_properties' => [
		  'comments',
      ],
      'id_properties' => [
          'postId',
      ],
      'urls' => [
          // Mandatory
          'self' => 'http://example.com/posts/{postId}',
          // Optional
          'comments' => 'http://example.com/posts/{postId}/comments',
      ],
      // (Optional) Used by HAL+JSON / HAL+XML
      'curies' => [
          'name' => 'example',
          'href' => 'http://example.com/docs/rels/{rel}',
      ],
      // (Optional) Used by JSONAPI
      'relationships' => [
          'author' => [
            'related' => 'http://example.com/posts/{postId}/author',
            'self' => 'http://example.com/posts/{postId}/relationships/author',
          ],
      ]
  ],
];

Quality

To run the PHPUnit tests at the command line, go to the tests directory and issue phpunit.

This library attempts to comply with PSR-1, PSR-2, PSR-4 and PSR-7.

If you notice compliance oversights, please send a patch via Pull Request.

Contribute

Contributions to the package are always welcome!

• Report any bugs or issues you find on the issue tracker.
• You can grab the source code at the package's Git repository.

Support

Get in touch with me using one of the following means:

• Emailing me at contact@nilportugues.com
• Opening an Issue

Authors

• Nil Portugués Calderó
• The Community Contributors

License

The code base is licensed under the MIT license.