Content Fields exposes filters and actions so you can change how values are read and written, override how post types and taxonomies register, and react when a definition changes — without touching plugin code.
What It Does
Nexter Extension 4.9.0 ships 18 filters and 4 actions in Content Fields. This page lists all of them with their signatures; the linked pages cover the ones you are most likely to use.
Before You Start
- Nexter Extension 4.9.0 or later with Content Fields enabled.
- Somewhere to add PHP — a child theme’s
functions.php, a small plugin, or a Nexter code snippet. - You know the field or post type key you want to affect.
Add a Hook
- Put the code in a child theme, a small plugin, or a Nexter code snippet — never in the plugin itself, which an update would overwrite.
- Hook early enough. Value filters run whenever a value is read or written, so ordinary
add_filter()placement is fine.
- Always return a value from a filter. Returning nothing replaces the value with
null.
- Check the field or key first, so your change applies only where you mean it to.
Display the Value
Every hook in Content Fields 4.9.0, with its signature:
// ---- Values -------------------------------------------------------------
apply_filters( 'nxt/format_value', $value, $field, $object_id );
apply_filters( 'nxt/update_value', $value, $field, $object_id );
apply_filters( 'nxt/pre_load_field', null, $selector, $object_id );
apply_filters( 'nxt/load_field', $value, $selector, $object_id );
apply_filters( 'nxt/pre_format_field_value', null, $value, $field );
apply_filters( 'nxt/pre_sanitize_field_value', null, $raw, $field, $renderer );
// ---- Field types and rendering ------------------------------------------
apply_filters( 'nxt/field_type_catalog', $catalog );
apply_filters( 'nxt/render_field_input', false, $field, $meta_key, $input_name, $value, $value_exists, $renderer );
// ---- Registration -------------------------------------------------------
apply_filters( 'nxt/register_post_type_args', $cpt_args, $key, $args );
apply_filters( 'nxt/register_taxonomy_args', $params, $key, $args );
apply_filters( 'nxt/validate_cpt_supports', null, $supports );
apply_filters( 'nxt/register_field_meta', true, $field, $meta_key, $object_type );
apply_filters( 'nxt/register_field_meta_args', $args, $field, $meta_key, $object_type );
apply_filters( 'nxt/pre_field_meta_rest_config', null, $field );
// ---- Migration ----------------------------------------------------------
apply_filters( 'nxt/import_sources', $sources );
// ---- Storage and capabilities -------------------------------------------
apply_filters( 'nexter_content_types_model_dir', $dir );
apply_filters( 'nexter_content_types_non_grantable_capabilities', $caps );
apply_filters( 'nexter_content_types_unsafe_capability_targets', $unsafe );
// ---- Actions ------------------------------------------------------------
do_action( 'nxt/definition_saved', $post_id, $kind, $meta );
do_action( 'nxt/definition_changed', $post_id, $kind );
do_action( 'nxt/registered_post_type', $key, $object, $args );
do_action( 'nxt/registered_taxonomy', $key, $object, $args );Limitations
- These hooks are specific to Nexter Content Fields. They are not compatible with ACF’s hooks, and ACF snippets will not work unchanged.
- Value filters run on every read or write of a field. Keep the callbacks cheap — a slow filter is felt on every page that renders fields.
- Hook names are a contract. Treat anything not listed here as internal and liable to change.
Troubleshooting
My filter runs but the value is unchanged
Check you are returning the value. A callback that ends without a return hands back null, and Nexter treats that as no value.
My filter affects every field, not one
Test the $field or $selector argument and return the original value untouched for everything else.
