Add Advanced Custom Fields Fields to the WP REST API

functions.php

function wp_api_encode_acf($data,$post,$context){
	$data['meta'] = array_merge($data['meta'],get_fields($post['ID']));
	return $data;
}

if( function_exists('get_fields') ){
	add_filter('json_prepare_post', 'wp_api_encode_acf', 10, 3);
}

Awesome!

I had to typecast the get_fields() returned value as an array. updated code below:

function wp_api_encode_acf($data,$post,$context){
    $customMeta = (array) get_fields($post['ID']);

    $data['meta'] = array_merge($data['meta'], $customMeta );
    return $data;
}

if( function_exists('get_fields') ){
    add_filter('json_prepare_post', 'wp_api_encode_acf', 10, 3);
}

Does this work in both directions? Can I push updates to the meta to change the ACFs programmatically?

This made my day. Well done!

This made my day too! I love you! :-)

Searched two hours before I found this. You're a legend! Thanks

Cool, this works! I created a plugin from this, as I prefered that over editing the main plugin. It is to be found at https://github.com/PanManAms/WP-JSON-API-ACF

I was having a problem with this when I tried to make a call to get a post without custom fields, meta data was being overwritten, so I changed the function to check first. Seems obvious, but was tearing my hair out over this for a while trying to figure out what was going wrong, so reposting in case it can help someone else.

function wp_api_encode_acf($data,$post,$context){
// check if custom fields exist for the post
$custom_fields_exist = get_fields($post['ID']);
if ($custom_fields_exist) {
$data['meta'] = array_merge($data['meta'], get_fields($post['ID']));
}
return $data;
}

Please note, because you do a check for get_fields in the code this will fail if this code loads before ACF

Can one also filter by these fields? posts/?filter[meta_key]=something

Great!
can I also EDIT acf metas ?
can you show me an example please?

it would be fantastic filter by meta the custom fields!

Great!

Hi there, any chance to get this done for taxonomies?

Hey I'm just now stumbling on this thread and I actually have added this plugin which does work, for the most part: https://wordpress.org/plugins/acf-to-wp-api/

The problem is that I have a custom taxonomy that's setup like an archive post, but it still has a bunch of ACF fields associated with it. When I view the posts in my browser, I get a "acf: false" key mapping for the custom post type, but for regular standard Wordpress posts, the ACF fields show up in the json api object. Does anyone have any clue why this would be happening? Am I missing something?

Hello, how do you use it ?
I tried : http://localhost/wp-json/wp/v2/posts/16/to retrieve all the post infos and but the meta section goes :

http://v2.wp-api.org/meta: [
    {
        embeddable: true,
        href: "http://localhost/wp-json/wp/v2/posts/16/meta"
    }
]

I can't see my custom fields, and when I try this link it returns 403 has I'm not logged, but I want this data to be public read only.
Thanks

I use the following when using v2 of https://github.com/WP-API/WP-API

function wp_rest_api_alter() {
  register_api_field( 'post',
      'fields',
      array(
        'get_callback'    => function($data, $field, $request, $type){
          if (function_exists('get_fields')) {
            return get_fields($data['id']);
          }
          return [];
        },
        'update_callback' => null,
        'schema'          => null,
      )
  );
}
add_action( 'rest_api_init', 'wp_rest_api_alter');

@davidmaneuver Thank you so much !

This is working with REST API v2 for me: https://github.com/airesvsg/acf-to-rest-api

I have created a custom post type and it has meta too. the custom post name is before_after and it is using multi post thumbnail library two metas are before_image and after_image, how i can add these two metas to REST API using the following code:

    function wp_api_encode_acf($data,$post,$context){

    $field_name = "after_image";
$data['mymeta'] = get_post_meta( $object[ 'id' ], $field_name );

return $data;
    }
    add_filter('json_prepare_post', 'wp_api_encode_acf', 10, 3);

Thank you!

The given solution didn't work for me on WordPress 5.2 but this works.

/**
 * Create REST field of ACF values for WordPress REST API
 */
function create_acf_fields_key_for_rest_api() {
	register_rest_field(
		[ 'post', 'page' ], // add post types here
		'acf_fields', // name of the field
		array(
			'get_callback'    => 'get_acf_fields_for_api',
			'update_callback' => null,
			'schema'          => null,
		)
	);
}
add_action( 'rest_api_init', 'create_acf_fields_key_for_rest_api' );

/**
 * Get ACF fields of the current post for the REST API field
 *
 * @param array $object post object array
 * @return array acf fields related to current post
 */
function get_acf_fields_for_api( $object ) {
	$data = get_fields( get_the_ID() );
	return $data ?: false;
}

@mehmoodak: Thank you :)

I am trying to send a post to my post type and it gives me an error, I am using custom field, help please, thank you

@albertoavv The REST route you are giving isn't correct. I didn't work with ACF REST API so please read their docs carefully. By the way I also thinks that in your path wp/wp5/wp-json should be changed to wp/wp-json

Thank you for your response, if what happens is that w5 is the name of the project or the root, but thanks for your response I will continue looking for a solution,

Regards

@mehmoodak thnx for your solution. Do you have any suggestion to specify only which ACF fields do you want to retrieve or not ?

great contribution @rileypaulsen! thanks. it works

Thanks @mehmoodak !

Thank you so much @mehmoodak !