JSON API to show Advanced Custom Fields - WordPress

Question

I am developing a magazine WordPress site that will have a json feed for a Mobile App. I set the backend up using Advanced Custom Fields with a Repeater Field for Multiple Artic

Answer 1

Current version of ACF prints out a custom_fields object on a call to the JSON API, containing all the fields relative to the Post or Page. I edited @Myke version to add specific custom fields from the ACF Option page to each Post or Page. Unfortunately there is not get_fields() function for the whole Option Page so you'll have to edit it depending on your fields structure.

add_filter('json_api_encode', 'json_api_encode_acf');

function json_api_encode_acf($response) {
    if (isset($response['posts'])) {
        foreach ($response['posts'] as $post) {
            json_api_add_acf($post); // Add specs to each post
        }
    }
    else if (isset($response['post'])) {
        json_api_add_acf($response['post']); // Add a specs property
    }
    else if (isset($response['page'])) {
        json_api_add_acf($response['page']); // Add a specs to a page
    }

    return $response;
}

function json_api_add_acf(&$post) {
    $post->custom_fields->NAME_OF_YOUR_CUSTOM_FIELD = get_field( 'NAME_OF_YOUR_CUSTOM_FIELD', 'option' );
}

Answer 2

Came here by searching with the same question. This isn't totally vetted yet but I think this is getting on the right path. Check it out.

I have one less nested level than you do so this might need altered a bit. But the JSON API plugin has a filter called json_api_encode. I have a repeater called specifications that looks like this.

http://d.pr/i/YMvv

In my functions file I have this.

add_filter('json_api_encode', 'my_encode_specs');

function my_encode_specs($response) {
  if (isset($response['posts'])) {
    foreach ($response['posts'] as $post) {
      my_add_specs($post); // Add specs to each post
    }
  } else if (isset($response['post'])) {
    my_add_specs($response['post']); // Add a specs property
  }
  return $response;
}

function my_add_specs(&$post) {
  $post->specs = get_field('specifications', $post->id);
}

Which appends a custom value to the JSON API output. Notice the get_field function from ACF works perfectly here for bringing back the array of the repeater values.

Hope this helps!

Answer 3

There is now a small plugin which adds the filter for you.

https://github.com/PanManAms/WP-JSON-API-ACF

Answer 4

I'm not sure if you're still interested in a solution, but I was able to modify the json-api plugin models/post.php file to display the repeater data as an array. This is a modification of a modification made by http://wordpress-problem.com/marioario-on-plugin-json-api-fixed-get-all-custom-fields-the-right-way/

replace the set_custom_fields_value() function with the following:

function set_custom_fields_value() {

    global $json_api;

    if ($json_api->include_value('custom_fields') && $json_api->query->custom_fields) {

        // Query string params for this query var
        $params = trim($json_api->query->custom_fields);

        // Get all custom fields if true|all|* is passed
        if ($params === "*" || $params === "true" || $params === "all") {

            $wp_custom_fields = get_post_custom($this->id);
            $this->custom_fields = new stdClass();

            // Loop through our custom fields and place on property
            foreach($wp_custom_fields as $key => $val) {
                if (get_field($key)) {
                    $this->custom_fields->$key = get_field($key);
                } else if ($val) {
                    // Some fields are stored as serialized arrays.
                    // This method does not support multidimensionals... 
                    // but didn't see anything wrong with this approach
                    $current_custom_field = @unserialize($wp_custom_fields[$key][0]);

                    if (is_array($current_custom_field)) {

                        // Loop through the unserialized array
                        foreach($current_custom_field as $sub_key => $sub_val) {

                            // Lets append these for correct JSON output
                            $this->custom_fields->$key->$sub_key = $sub_val;
                        }

                    } else {

                        // Break this value of this custom field out of its array
                        // and place it on the stack like usual
                        $this->custom_fields->$key = $wp_custom_fields[$key][0];

                    }
                }
            }
        } else {

            // Well this is the old way but with the unserialized array fix
            $params = explode(',', $params);
            $wp_custom_fields = get_post_custom($this->id);
            $this->custom_fields = new stdClass();

            foreach ($params as $key) {

                if (isset($wp_custom_fields[$key]) && $wp_custom_fields[$key][0] ) {
                    $current_custom_field = @unserialize($wp_custom_fields[$key][0]);

                    if (is_array($current_custom_field)) {
                        foreach($current_custom_field as $sub_key => $sub_val) {
                            $this->custom_fields->$key->$sub_key = $sub_val;
                        }

                    } else {
                        $this->custom_fields->$key = $wp_custom_fields[$key][0];

                    }

                }
            }
        }

    } else {
        unset($this->custom_fields);

    }
}

Answer 5

@Myke: you helped me tremendously. Here's my humble addition:

add_filter('json_api_encode', 'json_api_encode_acf');


function json_api_encode_acf($response) 
{
    if (isset($response['posts'])) {
        foreach ($response['posts'] as $post) {
            json_api_add_acf($post); // Add specs to each post
        }
    } 
    else if (isset($response['post'])) {
        json_api_add_acf($response['post']); // Add a specs property
    }

    return $response;
}

function json_api_add_acf(&$post) 
{
    $post->acf = get_fields($post->id);
}

Answer 6

Update for Wordpress 4.7

With the release of Wordpress 4.7 the REST functionality is no longer provided as a distinct plugin, rather its rolled in (no plugin required).

The previous filters don't appear to work. However the following snippet does (can be in your functions.php):

>= PHP 5.3

add_filter('rest_prepare_post', function($response) {
    $response->data['acf'] = get_fields($response->data['id']);
    return $response;
});

< PHP 5.3

add_filter('rest_prepare_post', 'append_acf');

function append_acf($response) {
    $response->data['acf'] = get_fields($response->data['id']);
    return $response;
};

Note the filter is a wild card filter, applied like

apply_filters("rest_prepare_$type", ...

so if you have multiple content types (custom), you will need to do:

add_filter('rest_prepare_multiple_choice', 'append_acf');
add_filter('rest_prepare_vocabularies', 'append_acf');

function append_acf($response) {
    $response->data['acf'] = get_fields($response->data['id']);
    return $response;
};

Note It appears that rest_prepare_x is called per record. So if you are pinging the index endpoint, it will be called multiple times (so you don't need to check if its posts or post)