I got an interesting question from @slotty7130 in the WordPress.org support forums today: they wanted to use the REST API Post Embeds plugin to display posts from one of their websites, but only in a specific language as defined in WPML.
If you’re not familiar with REST API Post Embeds, my plugin defines a shortcode that runs REST API queries for you, using the WP REST API or the WordPress.com REST API. The shortcode accepts several parameters, but I didn’t build in any language parameter, as none of the APIs support it by default. Luckily, it looks like someone already developed a plugin that adds a lang parameter to the WP API, to query for specific WPML posts.
All we have to do now is:
- Add a new parameter to my shortcode;
- If that parameter is set in the post editor, alter the WP REST API query to include that parameter.
The former can be achieved with the shortcode_atts_{$shortcode} filter. The latter can be done thanks to the jeherve_post_embed_query_url filter in my plugin.
/**
* Add new lang parameter to the shortcode.
*
* Must be used with a plugin that will allow you to retrieve specific posts
* from the WP REST API when you add the `lang` parameter. This plugin seems to do the trick:
* https://wordpress.org/plugins/wp-rest-api-multilanguage-over-wmpl/
*
* @see https://wordpress.org/support/topic/retrieving-wmpl-posts
*
* @param array $out The output array of shortcode attributes.
* @param array $pairs The supported attributes and their defaults.
* @param array $atts The user defined shortcode attributes.
* @param string $shortcode The shortcode name.
*/
function jeherve_rest_api_embeds_lang( $out, $pairs, $atts, $shortcode ) {
if ( isset( $atts['lang'] ) && '' != $atts['lang'] ) {
$out['lang'] = $atts['lang'];
}
return $out;
}
add_filter( 'shortcode_atts_jeherve_post_embed', 'jeherve_rest_api_embeds_lang', 10, 4 );
/**
* Use the new shortcode parameter in the REST API Post Queries.
*/
function jeherve_rest_api_embed_lang_query( $url, $atts, $args ) {
if (
// If a lang parameter was added as a shortcode, and if it is not empty
( isset( $atts['lang'] ) && '' != $atts['lang'] )
// If we are doing a WP REST API query, not a WordPress.com REST API one
&& ( isset( $atts['wpapi'] ) && true === $atts['wpapi'] )
) {
$url = add_query_arg(
array( 'lang' => esc_attr( $atts['lang'] ) ),
$url
);
}
return $url;
}
add_filter( 'jeherve_post_embed_query_url', 'jeherve_rest_api_embed_lang_query', 11, 3 );
Et voilà! I must admit that extending existing plugins without touching the plugin code is one of my favourite pastimes ?
