REST filters only firing when I have a param set

I’m trying to use a REST filter to require a certain parameter is set.

Using custom taxonomies and custom posts I’ve been able to make it so when I request

/wp-json/wp/v2/car?visible_to=123

That the only Cars that come back are ones with a visible_to taxonomy of 123.

However when someone asks for

/wp-json/wp/v2/car

I want to throw an error, saying that ?visible_to needs to be set.

I’ve tried hooking into rest_index, rest_pre_dispatch, and some others. Each only fires when I have ?visible_to set in the URL, without them the hooks don’t fire.

For example, I would expect this to fire on every REST request

add_filter( 'rest_pre_dispatch','to_limit_access', 1, 3);

function to_limit_access($args, $request, $context) {
  return new WP_Error( 'rest_disabled', __( 'The REST API is disabled on this site.' ), array( 'status' => 404 ) );
}

But it will only return a WP_Error on

/wp-json/wp/v2/car?visible_to=123

Both

/wp-json/wp/v2/car

And

/wp-json/wp/v2/car/6

Run without that filter being hit.

Can someone explain why this would be the case and what I can do to avoid it?

I’ve also tried specific filters like rest_prepare_car but I couldn’t get it to fire at all.

Answers:

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Method 1

If you want a parameter to be required for a post type’s REST API endpoint you can use the rest_{$this->post_type}_collection_params filter to filter the $args of the GET endpoint:

add_filter(
    'rest_car_collection_params',
    function( array $query_params ) {
        $query_params['visible_to']['required'] = true;
        
        return $query_params;
    }
);

Method 2

In turns out we had a caching plugin enabled that was getting in the way of some requests but not others, leading to this inconsistency.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0