Manipulate wordpress REST API search query

Question

I want to add a custom field to be included into my search query. That's done via meta_query, I am fully aware of that but the issue is, I don't know, where to hang into to manipulate the query args to my needs.

So I am looking for a filter, to to get into REST API search request (/wp/v2/search), any clue?

Answer 1

You can implement the following hook:

add_filter( 'rest_post_search_query', 'rest_search_add_custom_field_cb', 10, 2 );
function rest_search_add_custom_field_cb( $query_args, $request ) {
    // filter...

    return $query_args;
}

You can modify the search query and include additional params like meta query, etc.

The return value of this filter will be used by WordPress in the following context:

...
$query->query( $query_args );
...