utf8 encoding in json rest api

Question

i create a custom REST API to get posts

add_action( 'rest_api_init', 'custom_api_get_all_posts' ); 



function custom_api_get_all_posts() {
    register_rest_route( 'custom/v1', '/all-posts', array(
        'methods' => 'GET',
        'callback' => 'custom_api_get_all_posts_callback'
    ));
}

function custom_api_get_all_posts_callback( $request ) {
    // Initialize the array that will receive the posts' data. 
    $posts_data = array();
    // Receive and set the page parameter from the $request for pagination purposes
    $paged = $request->get_param( 'page' );
    $paged = ( isset( $paged ) || ! ( empty( $paged ) ) ) ? $paged : 1; 
    // Get the posts using the 'post' and 'news' post types
    $posts = get_posts( array(
            'paged' => $paged,
            'post__not_in' => get_option( 'sticky_posts' ),
            'posts_per_page' => 10,            
            'post_type' => listing,
            'tax_query' => array(
                array (
                'taxonomy' => 'flux_rss',
                'field' => 'slug',
                'terms' => 'oui',
                )
            ), 
        )
    ); 


// Loop through the posts and push the desired data to the array we've initialized earlier in the form of an object
foreach( $posts as $post ) {

    $id = $post->ID; 
    $post_thumbnail = ( has_post_thumbnail( $id ) ) ? get_the_post_thumbnail_url( $id ) : null;

    $posts_data[] = (object) array( 
        'id' => $id, 
        'title' => $post->post_title,
        'excerpt' => wp_json_encode($post->post_excerpt), 
        'link' => $post->guid,
        'featured_img_src' => $post_thumbnail
    );
}                  
return $posts_data;                   

}

But i get some special character in the response so how i can transform json response to utf8

[{
    "id": 2087,
    "title": "Avec l\u2019ONPA",
    "excerpt": "\"Avec cette association cr\\u00e9\\u00e9e en 1971, les s\\u00e9niors de 55 ans et plus, en activit\\u00e9 professionnelle ou non, et vivant \\u00e0 domicile, m\\u00e8nent une vie active...\"",
    "link": "http:\/\/localhost\/focus\/?post_type=listing&p=2087",
    "featured_img_src": "http:\/\/localhost\/focus\/wp-content\/uploads\/2018\/05\/avec-lonpa.jpg"
},

Answer 1

The problem is here:

'excerpt' => wp_json_encode($post->post_excerpt), 

That array will get passed through wp_json_encode by the REST API, so it gets double encoded, so remove the wp_json_encode here, and it'll work out fine, it's just encoding, it's not the literal human readable value.

E.g. put it in your browsers dev console and output the result, and you'll see it's a non-issue:

As you can see, ’ was encoded as \u2019O because 20190 is the unicode character code of ’, and HTML can't natively use those characters without some form of encoding. That's why when you inspect HTML, you'll see & but when you view it in the browser you see &, the same thing is happening here