Filtering multiple custom fields with WP REST API 2

Question

I want to filter posts based on multiple acf custom fields with AND relation. Something like this:

$args = array(
        'post_type'  => 'product',
        'meta_query' => array(
            'relation' => 'AND',
            array(
                'key'     => 'color',
                'value'   => 'blue',
                'compare' => '=',
            ),
            array(
                'key'     => 'price',
                'value'   => array( 20, 100 ),
                'type'    => 'numeric',
                'compare' => 'BETWEEN',
            ),
        ),
    );

I might even have more filters. How can I convert these to REST API 2 filters?

Answer 1

This solution works with get_items() in /lib/endpoints/class-wp-rest-posts-controller.php of the v2 WP Rest API.

---

First, you'll want to construct the GET arguments like you would for a new WP_Query(). The easiest way to do this is with http_build_query().

$args = array (
    'filter' => array (
        'meta_query' => array (
            'relation' => 'AND',
            array (
                'key'     => 'color',
                'value'   => 'blue',
                'compare' => '=',
            ),
            array (
                'key'     => 'test',
                'value'   => 'testing',
                'compare' => '=',
            ),
        ),
    ),
);
$field_string = http_build_query( $args );

It'll produce something like:

filter%5Bmeta_query%5D%5Brelation%5D=AND&filter%5Bmeta_query%5D%5B0%5D%5Bkey%5D=color&filter%5Bmeta_query%5D%5B0%5D%5Bvalue%5D=blue&filter%5Bmeta_query%5D%5B0%5D%5Bcompare%5D=%3D&filter%5Bmeta_query%5D%5B1%5D%5Bkey%5D=test&filter%5Bmeta_query%5D%5B1%5D%5Bvalue%5D=testing&filter%5Bmeta_query%5D%5B1%5D%5Bcompare%5D=%3D

Which, if you want readable, you can also use Chrome tools and decodeURIComponent('your-query-here') to make it a easier to read when you throw it into your JSON Rest API URL:

https://demo.wp-api.org/wp-json/wp/v2/product?filter[meta_query][relation]=AND&filter[meta_query][0][key]=color&filter[meta_query][0][value]=blue&filter[meta_query][0][compare]==&filter[meta_query][1][key]=test&filter[meta_query][1][value]=testing&filter[meta_query][1][compare]==

Note: To use your custom post type you would put product before ?

/wp-json/wp/v2/<custom-post-type>?filter[meta_query]

---

So you have your query but we need to instruct WP how to handle a few things:

1. Adding REST support for the custom post type product
2. Allowing the query args meta_query
3. Parsing meta_query

---

// 1) Add CPT Support <product>


function wpse_20160526_add_product_rest_support() {
    global $wp_post_types;

    //be sure to set this to the name of your post type!
    $post_type_name = 'product';
    if( isset( $wp_post_types[ $post_type_name ] ) ) {
        $wp_post_types[$post_type_name]->show_in_rest = true;
        $wp_post_types[$post_type_name]->rest_base = $post_type_name;
        $wp_post_types[$post_type_name]->rest_controller_class = 'WP_REST_Posts_Controller';
    }
}

add_action( 'init', 'wpse_20160526_add_product_rest_support', 25 );


// 2) Add `meta_query` support in the GET request

function wpse_20160526_rest_query_vars( $valid_vars ) {
    $valid_vars = array_merge( $valid_vars, array(  'meta_query'  ) ); // Omit meta_key, meta_value if you don't need them
    return $valid_vars;
}

add_filter( 'rest_query_vars', 'wpse_20160526_rest_query_vars', PHP_INT_MAX, 1 );


// 3) Parse Custom Args

function wpse_20160526_rest_product_query( $args, $request ) {

    if ( isset( $args[ 'meta_query' ] ) ) {

        $relation = 'AND';
        if( isset($args['meta_query']['relation']) && in_array($args['meta_query']['relation'], array('AND', 'OR'))) {
            $relation = sanitize_text_field( $args['meta_query']['relation'] );
        }
        $meta_query = array(
            'relation' => $relation
        );

        foreach ( $args['meta_query'] as $inx => $query_req ) {
        /*
            Array (

                [key] => test
                [value] => testing
                [compare] => =
            )
        */
            $query = array();

            if( is_numeric($inx)) {

                if( isset($query_req['key'])) {
                    $query['key'] = sanitize_text_field($query_req['key']);
                }
                if( isset($query_req['value'])) {
                    $query['value'] = sanitize_text_field($query_req['value']);
                }
                if( isset($query_req['type'])) {
                    $query['type'] = sanitize_text_field($query_req['type']);
                }
                if( isset($query_req['compare']) && in_array($query_req['compare'], array('=', '!=', '>','>=','<','<=','LIKE','NOT LIKE','IN','NOT IN','BETWEEN','NOT BETWEEN', 'NOT EXISTS')) ) {
                    $query['compare'] = sanitize_text_field($query_req['compare']);
                }
            }

            if( ! empty($query) ) $meta_query[] = $query;
        }

        // replace with sanitized query args
        $args['meta_query'] = $meta_query;
    }

    return $args;
}
add_action( 'rest_product_query', 'wpse_20160526_rest_product_query', 10, 2 );

Answer 2

Here is a test i made on Localhost:

For security reasons meta query is not allowed on WP Api, first what you have to do is to add meta_query to allowed rest_query by adding this function on your wordpress theme functions.php

function api_allow_meta_query( $valid_vars ) {

  $valid_vars = array_merge( $valid_vars, array( 'meta_query') );
  return $valid_vars;
}
add_filter( 'rest_query_vars', 'api_allow_meta_query' );

after that you will need build the html query by using this function on the other website that will get the data from the wordpress website

$curl = curl_init();
$fields = array (
  'filter[meta_query]' => array (
    'relation' => 'AND',
      array (
        'key' => 'color',
        'value' => 'blue',
        'compare' => '='
      ),
      array (
        'key' => 'price',
        'value' => array ( 20, 100 ),
        'type' => 'numeric',
        'compare' => 'BETWEEN'
      ),
    ),
  );

$field_string = http_build_query($fields);

curl_setopt_array($curl, array (
    CURLOPT_RETURNTRANSFER => 1,
    CURLOPT_URL => 'http://yourwordpreswebssite.com/wp-json/wp/v2/posts?' . $field_string
  )
);

$result = curl_exec($curl);

echo htmlentities($result);

I change the fields array so the look now like your query arguments. The encoded query string will look like this:

http://yourwordpreswebssite.com/wp-json/wp/v2/posts?filter%5Btaxonomy%5D=product&filter%5Bmeta_query%5D%5Brelation%5D=AND&filter%5Bmeta_query%5D%5B0%5D%5Bkey%5D=color&filter%5Bmeta_query%5D%5B0%5D%5Bvalue%5D=blue&filter%5Bmeta_query%5D%5B0%5D%5Bcompare%5D=%3D&filter%5Bmeta_query%5D%5B1%5D%5Bkey%5D=price&filter%5Bmeta_query%5D%5B1%5D%5Bvalue%5D%5B0%5D=20&filter%5Bmeta_query%5D%5B1%5D%5Bvalue%5D%5B1%5D=100&filter%5Bmeta_query%5D%5B1%5D%5Btype%5D=numeric&filter%5Bmeta_query%5D%5B1%5D%5Bcompare%5D=BETWEEN

By using urldecode(), which in this case will be: urldecode('http://yourwordpreswebssite.com/wp-json/wp/v2/posts?' . $field_string); you will have an URL like this one:

http://yourwordpreswebssite.com/wp-json/wp/v2/posts?filter[taxonomy]=product&filter[meta_query][relation]=AND&filter[meta_query][0][key]=color&filter[meta_query][0][value]=blue&filter[meta_query][0][compare]==&filter[meta_query][1][key]=price&filter[meta_query][1][value][0]=20&filter[meta_query][1][value][1]=100&filter[meta_query][1][type]=numeric&filter[meta_query][1][compare]=BETWEEN

If you can provide us your live website URL so we can test it using postman directly on your website, because to test it on localhost or any existing WordPress site will be needed to create product custom post type and add meta fields etc etc. Cheers!

Answer 3

1. first add plugin or copy all code and paste all plugin in functions.php of this link https://github.com/WP-API/rest-filter
2. use this

?filter[meta_query][relation]=AND
&filter[meta_query][0][key]=REAL_HOMES_property_price
&filter[meta_query][0][value][0]=10
&filter[meta_query][0][value][1]=10000001
&filter[meta_query][0][compare]=''
&filter[meta_query][1][key]=REAL_HOMES_property_price
&filter[meta_query][1][value]=10
&filter[meta_query][1][compare]='='

Answer 4

You can do it without Rest API Like this (It is my posts filter)

    $paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
$args = array(
        'paged' => $paged,
        'orderby' => 'date', // сортировка по дате у нас будет в любом случае (но вы можете изменить/доработать это)
        'order' => 'DESC',
    );

    // создаём массив $args['meta_query'] если указана хотя бы одна цена или отмечен чекбокс
    if( isset( $_GET['price_min'] ) || isset( $_GET['price_max'] ) || isset( $_GET['type'] ) )
        $args['meta_query'] = array( 'relation'=>'AND' ); // AND значит все условия meta_query должны выполняться


    if( $type ){
        $args['meta_query'][] = array(
            'key' => 'type',
            'value' => $type,
        );
    };

    if( $plan ){
        $args['meta_query'][] = array(
            'key' => 'plan',
            'value' => $plan,
        );
    };

    if( $room_num ){
        $args['meta_query'][] = array(
            'key' => 'room_num',
            'value' => $room_num,
        );
    };

    if( $etage ){
        $args['meta_query'][] = array(
            'key' => 'etage',
            'value' => $etage,
        );
    };  

    if( $price_min || $price_max ){
        $args['meta_query'][] = array(
            'key' => 'price',
            'value' => array( $price_min, $price_max ),
            'type' => 'numeric',
            'compare' => 'BETWEEN'
        );
    };  

    if( $area_min || $area_max ){
        $args['meta_query'][] = array(
            'key' => 'area',
            'value' => array( $area_min, $area_max ),
            'type' => 'numeric',
            'compare' => 'BETWEEN'
        );
    };

Answer 5

In Wordpress 4.7 the filter argument has been removed.

You can reactivate it installing this plugin provided by the Wordpress team. Only after that you can use one of the solutions proposed in the other answers.

I've haven't found a solution to do the same without installing the plugin, yet.