craftcms/element-api

Create a JSON API for your elements in Craft

2.5.2 2017-12-13 11:16 UTC

README

This plugin makes it easy to create a JSON API for your entries (and other element types) in Craft CMS.

It’s powered by Phil Sturgeon’s excellent Fractal package.

Requirements

This plugin requires Craft CMS 3.0.0-beta.20 or later.

Installation

To install the plugin, follow these instructions.

  1. Open your terminal and go to your Craft project:

     cd /path/to/project
    
  2. Then tell Composer to load the plugin:

     composer require craftcms/element-api
    
  3. In the Control Panel, go to Settings → Plugins and click the “Install” button for Element API.

Setup

To define your API endpoints, create a new element-api.php file within your craft/config/ folder. This file should return an array with an endpoints key, which defines your site’s API endpoints. Within the endpoints array, keys are URL patterns, and values are endpoint configurations.

<?php

use craft\elements\Entry;
use craft\helpers\UrlHelper;

return [
    'endpoints' => [
        'news.json' => [
            'elementType' => Entry::class,
            'criteria' => ['section' => 'news'],
            'transformer' => function(Entry $entry) {
                return [
                    'title' => $entry->title,
                    'url' => $entry->url,
                    'jsonUrl' => UrlHelper::url("news/{$entry->id}.json"),
                    'summary' => $entry->summary,
                ];
            },
        ],
        'news/<entryId:\d+>.json' => function($entryId) {
            return [
                'elementType' => Entry::class,
                'criteria' => ['id' => $entryId],
                'one' => true,
                'transformer' => function(Entry $entry) {
                    return [
                        'title' => $entry->title,
                        'url' => $entry->url,
                        'summary' => $entry->summary,
                        'body' => $entry->body,
                    ];
                },
            ];
        },
    ]
];

Endpoint Configuration Settings

Endpoint configuration arrays can contain the following settings:

class

The class name of the Fractal resource that should be used to serve the request. If this isn’t set, it will default to craft\elementapi\resources\ElementResource. (All of the following configuration settings are specific to that default class.)

elementType (Required)

The class name of the element type that the API should be associated with. Craft’s built-in element type classes are:

  • craft\elements\Asset
  • craft\elements\Category
  • craft\elements\Entry
  • craft\elements\GlobalSet
  • craft\elements\MatrixBlock
  • craft\elements\Tag
  • craft\elements\User
'elementType' => craft\elements\Entry::class,

criteria

An array of parameters that should be set on the Element Query that will be fetching the elements.

'criteria' => [
    'section' => 'news',
    'type' => 'article',
],

transformer

The transformer that should be used to define the data that should be returned for each element. If you don’t set this, the default transformer will be used, which includes all of the element’s direct attribute values, but no custom field values.

// Can be set to a function
'transformer' => function(craft\elements\Entry $entry) {
    return [
        'title' => $entry->title,
        'id' => $entry->id,
        'url' => $entry->url,
    ];
},

// Or a string/array that defines a Transformer class configuration
'transformer' => 'MyTransformerClassName',

// Or a Transformer class instance
'transformer' => new MyTransformerClassName(),

Your custom transformer class would look something like this:

<?php

use craft\elements\Entry;
use League\Fractal\TransformerAbstract;

class MyTransformerClassName extends TransformerAbstract
{
    public function transform(Entry $entry)
    {
        return [
            // ...
        ];
    }
}

one

Whether only the first matching element should be returned. This is set to false by default, meaning that all matching elements will be returned.

'one' => true,

paginate

Whether the results should be paginated. This is set to true by default, meaning that only a subset of the matched elements will be included in each response, accompanied by additional metadata that describes pagination information.

'paginate' => false,

elementsPerPage

The max number of elements that should be included in each page, if pagination is enabled. By default this is set to 100.

'elementsPerPage' => 10,

pageParam

The query string param name that should be used to identify which page is being requested. By default this is set to 'page'.

'pageParam' => 'pg',

Note that it cannot be set to 'p' because that’s the parameter Craft uses to check the requested path.

resourceKey

The key that the elements should be nested under in the response data. By default this will be 'data'.

'resourceKey' => 'entries',

meta

Any custom meta values that should be included in the response data.

'meta' => [
    'description' => 'Recent news from Happy Lager',
],

serializer

The serializer that should be used to format the returned data.

Possible values are:

includes

The include names that should be included for the current request, if any.

'includes' => Craft::$app->request->getQueryParam('include'),

Note that this setting requires a custom transformer class that’s prepped to handle includes:

class MyTransformerClassName extends TransformerAbstract
{
    protected $availableIncludes = ['author'];

    public function includeAuthor(Entry $entry)
    {
        return $this->item($entry->author, function(User $author) {
            return [
                'id' => $author->id,
                'name' => $author->name,
            ];
        });
    }

    // ...
}

excludes

The include names that should be excluded for the current request, which would otherwise have been included (e.g. if they were listed as a default include), if any.

'excludes' => 'author',

Like includes, this setting requires a custom transformer class.

jsonOptions

The value of the $options argument that will be passed to json_encode() when preparing the response. By default JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE will be passed.

'jsonOptions' => JSON_UNESCAPED_UNICODE,

pretty

Shortcut for adding JSON_PRETTY_PRINT to jsonOptions.

'pretty' => true,

cache

Whether the output should be cached, and for how long.

Possible values are:

  • false (default) – results are never cached
  • true – results are cached for the duration specified by the cacheDuration Craft config setting
  • an integer – results are cached for the given number of seconds
  • a interval spec string – results are cached for the duration specified

Note that the onBeforeSendData event does not get triggered when the cache is warm.

'cache' => 'PT1M', // one minute

Dynamic URL Patterns and Endpoint Configurations

URL patterns can contain dynamic subpatterns in the format of <subpatternName:regex>, where subpatternName is the name of the subpattern, and regex is a valid regular expression. For example, the URL pattern “news/<entryId:\d+>.json” will match URLs like news/100.json. You can also use the tokens {handle} and {slug} within your regular expression, which will be replaced with the appropriate regex patterns for matching handles and element slugs.

Endpoint configurations can also be dynamic, by using a function instead of an array. If you do this, the function should return an array of configuration settings. Any subpattern matches in the URL pattern will be mapped to the function’s arguments. For example, if a URL pattern contains an entryId subpattern, and the endpoint configuration is a function with an $entryId argument, then whatever matches the URL subpattern will be passed to that function argument. This makes it easy to modify the resulting endpoint configuration based on the URL subpattern matches.

'news/<entryId:\d+>.json' => function($entryId) {
    return [
        'elementType' => craft\elements\Entry::class,
        'criteria' => ['id' => $entryId],
        'one' => true,
    ];
},

Setting Default Configuration Settings

You can specify default values for your endpoint configuration settings by adding a defaults key alongside your endpoints key (not within it).

use craft\elements\Entry;

return [
    'defaults' => [
        'elementType' => Entry::class,
        'elementsPerPage' => 10,
        'pageParam' => 'pg',
        'transformer' => function(Entry $entry) {
            return [
                'title' => $entry->title,
                'id' => $entry->id,
                'url' => $entry->url,
            ];
        },
    ],

    'endpoints' => [
        'news.json' => [
            'criteria' => ['section' => 'news'],
        ],
        'news/<entryId:\d+>.json' => function($entryId) {
            return [
                'criteria' => ['id' => $entryId],
                'one' => true,
            ];
        },
    ]
];

Entry Drafts and Versions

Element API provides an entry-specific Fractal resource that adds draftId and versionId configuration settings. To use it, set the class configuration setting to 'craft\elementapi\resources\EntryResource'.

If draftId and versionId are not set, it will behave identically to the default Fractal resource. If either of them are set, the criteria setting will be ignored, and only the requested entry draft/version will be returned.

It’s probably a good idea to add some level of authentication to your endpoint before setting draftId or versionId.

'news/<entryId:\d+>.json' => function($entryId) {
    if ($draftId = Craft::$app->request->getQueryParam('draftId')) {
        // Make sure they have permission to view drafts
        $user = Craft::$app->user->getIdentity();
        if (!$user || (!$user->admin && !$user->isInGroup('authors'))) {
            throw new \yii\web\ForbiddenHttpException('You must be an author to access drafts!');
        }
    }

    return [
        'class' => craft\elementapi\resources\EntryResource::class,
        'criteria' => ['id' => $entryId],
        'draftId' => $draftId,
        'one' => true,
    ];
},

Examples

Here are a few endpoint examples, and what their response would look like.

Paginated Entry Index Endpoint

'ingredients.json' => [
    'criteria' => ['section' => 'ingredients'],
    'elementsPerPage' => 10,
    'transformer' => function(craft\elements\Entry $entry) {
        return [
            'title' => $entry->title,
            'url' => $entry->url,
            'jsonUrl' => UrlHelper::url("ingredients/{$entry->slug}.json"),
        ];
    },
    'pretty' => true,
],
{
    "data": [
        {
            "title": "Gin",
            "url": "/ingredients/gin",
            "jsonUrl": "/ingredients/gin.json"
        },
        {
            "title": "Tonic Water",
            "url": "/ingredients/tonic-water",
            "jsonUrl": "/ingredients/tonic-water.json"
        },
        // ...
    ],
    "meta": {
        "pagination": {
            "total": 66,
            "count": 10,
            "per_page": 10,
            "current_page": 1,
            "total_pages": 7,
            "links": {
                "next": "/ingredients.json?p=2"
            }
        }
    }
}

Single Entry Endpoint

'ingredients/<slug:{slug}>.json' => function($slug) {
    return [
        'criteria' => [
            'section' => 'ingredients',
            'slug' => $slug
        ],
        'one' => true,
        'transformer' => function(craft\elements\Entry $entry) {
            // Create an array of all the photo URLs
            $photos = [];
            foreach ($entry->photos as $photo) {
                $photos[] = $photo->url;
            }

            return [
                'title' => $entry->title,
                'url' => $entry->url,
                'description' => (string) $entry->description,
                'photos' => $photos
            ];
        },
        'pretty' => true,
    ];
},
{
    "title": "Gin",
    "url": "/ingredients/gin",
    "description": "<p>Gin is a spirit which derives its predominant flavour from juniper berries.</p>",
    "photos": [
        "/images/drinks/GinAndTonic1.jpg"
    ]
}

JSON Feed

Here’s how to set up a JSON Feed (Version 1) for your site with Element API.

Note that photos, body, summary, and tags are imaginary custom fields.

'feed.json' => [
    'serializer' => 'jsonFeed',
    'elementType' => craft\elements\Entry::class,
    'criteria' => ['section' => 'news'],
    'transformer' => function(craft\elements\Entry $entry) {
        $image = $entry->photos->first();

        return [
            'id' => (string) $entry->id,
            'url' => $entry->url,
            'title' => $entry->title,
            'content_html' => (string) $entry->body,
            'summary' => $entry->summary,
            'image' => $image ? $image->url : null,
            'date_published' => $entry->postDate->format(\DateTime::ATOM),
            'date_modified' => $entry->dateUpdated->format(\DateTime::ATOM),
            'author' => ['name' => $entry->author->name],
            'tags' => array_map('strval', $entry->tags->find()),
        ];
    },
    'meta' => [
        'description' => 'Recent news from Happy Lager',
    ],
    'pretty' => true,
]
{
    "version": "https://jsonfeed.org/version/1",
    "title": "Happy Lager",
    "home_page_url": "http://domain.com/",
    "feed_url": "http://domain.com/feed.json",
    "description": "Craft demo site",
    "items": [
        {
            "id": "24",
            "url": "http://domain.com/news/the-future-of-augmented-reality",
            "title": "The Future of Augmented Reality",
            "content_html": "<p>Nam libero tempore, cum soluta nobis est eligendi ...</p>",
            "date_published": "2016-05-07T00:00:00+00:00",
            "date_modified": "2016-06-03T17:43:36+00:00",
            "author": {
                "name": "Liz Murphy"
            },
            "tags": [
                "augmented reality",
                "futurism"
            ]
        },
        {
            "id": "4",
            "url": "http://domain.com/news/barrel-aged-digital-natives",
            "title": "Barrel Aged Digital Natives",
            "content_html": "<p>Nam libero tempore, cum soluta nobis est eligendi ...</p>",,
            "date_published": "2016-05-06T00:00:00+00:00",
            "date_modified": "2017-05-18T13:20:27+00:00",
            "author": {
                "name": "Liz Murphy"
            },
            "tags": [
                "barrel-aged"
            ]
        },
        // ...
    ]
}