lib/fields/class-wp-rest-meta-fields.php
<?php
/**
* Manage meta values for an object.
*/
abstract class WP_REST_Meta_Fields {
/**
* Get the object type for meta.
*
* @return string One of 'post', 'comment', 'term', 'user', or anything
* else supported by `_get_meta_table()`.
*/
abstract protected function get_meta_type();
/**
* Get the object type for `register_rest_field`.
*
* @return string Custom post type, 'taxonomy', 'comment', or `user`.
*/
abstract protected function get_rest_field_type();
/**
* Register the meta field.
*/
public function register_field() {
register_rest_field( $this->get_rest_field_type(), 'meta', array(
'get_callback' => array( $this, 'get_value' ),
'update_callback' => array( $this, 'update_value' ),
'schema' => $this->get_field_schema(),
));
}
/**
* Get the `meta` field value.
*
* @param int $object_id Object ID to fetch meta for.
* @param WP_REST_Request $request Full details about the request.
* @return WP_Error|object
*/
public function get_value( $object_id, $request ) {
$fields = $this->get_registered_fields();
$response = array();
foreach ( $fields as $name => $args ) {
$all_values = get_metadata( $this->get_meta_type(), $object_id, $name, false );
if ( $args['single'] ) {
if ( empty( $all_values ) ) {
$value = $args['schema']['default'];
} else {
$value = $all_values[0];
}
$value = $this->prepare_value_for_response( $value, $request, $args );
} else {
$value = array();
foreach ( $all_values as $row ) {
$value[] = $this->prepare_value_for_response( $row, $request, $args );
}
}
$response[ $name ] = $value;
}
return (object) $response;
}
/**
* Prepare value for response.
*
* This is required because some native types cannot be stored correctly in
* the database, such as booleans. We need to cast back to the relevant
* type before passing back to JSON.
*
* @param mixed $value Value to prepare.
* @param WP_REST_Request $request Current request object.
* @param array $args Options for the field.
* @return mixed Prepared value.
*/
protected function prepare_value_for_response( $value, $request, $args ) {
if ( ! empty( $args['prepare_callback'] ) ) {
$value = call_user_func( $args['prepare_callback'], $value, $request, $args );
}
return $value;
}
/**
* Update meta values.
*
* @param WP_REST_Request $request Full details about the request.
* @param int $object_id Object ID to fetch meta for.
* @return WP_Error|null Error if one occurs, null on success.
*/
public function update_value( $request, $object_id ) {
$fields = $this->get_registered_fields();
foreach ( $fields as $name => $args ) {
if ( ! array_key_exists( $name, $request ) ) {
continue;
}
// A null value means reset the field, which is essentially deleting it
// from the database and then relying on the default value.
if ( is_null( $request[ $name ] ) ) {
$result = $this->delete_meta_value( $object_id, $name );
} elseif ( $args['single'] ) {
$result = $this->update_meta_value( $object_id, $name, $request[ $name ] );
} else {
$result = $this->update_multi_meta_value( $object_id, $name, $request[ $name ] );
}
if ( is_wp_error( $result ) ) {
return $result;
}
}
return null;
}
/**
* Delete meta value for an object.
*
* @param int $object_id Object ID the field belongs to.
* @param string $name Key for the field.
* @return bool|WP_Error True if meta field is deleted, error otherwise.
*/
protected function delete_meta_value( $object_id, $name ) {
if ( ! current_user_can( 'delete_post_meta', $object_id, $name ) ) {
return new WP_Error(
'rest_cannot_delete',
sprintf( __( 'You do not have permission to edit the %s custom field.' ), $name ),
array( 'key' => $name, 'status' => rest_authorization_required_code() )
);
}
if ( ! delete_metadata( $this->get_meta_type(), $object_id, wp_slash( $name ) ) ) {
return new WP_Error(
'rest_meta_database_error',
__( 'Could not delete meta value from database.' ),
array( 'key' => $name, 'status' => WP_Http::INTERNAL_SERVER_ERROR )
);
}
return true;
}
/**
* Update multiple meta values for an object.
*
* Alters the list of values in the database to match the list of provided values.
*
* @param int $object_id Object ID to update.
* @param string $name Key for the custom field.
* @param array $values List of values to update to.
* @return bool|WP_Error True if meta fields are updated, error otherwise.
*/
protected function update_multi_meta_value( $object_id, $name, $values ) {
if ( ! current_user_can( 'edit_post_meta', $object_id, $name ) ) {
return new WP_Error(
'rest_cannot_update',
sprintf( __( 'You do not have permission to edit the %s custom field.' ), $name ),
array( 'key' => $name, 'status' => rest_authorization_required_code() )
);
}
$current = get_metadata( $this->get_meta_type(), $object_id, $name, false );
$to_remove = $current;
$to_add = $values;
foreach ( $to_add as $add_key => $value ) {
$remove_keys = array_keys( $to_remove, $value, true );
if ( empty( $remove_keys ) ) {
continue;
}
if ( count( $remove_keys ) > 1 ) {
// To remove, we need to remove first, then add, so don't touch.
continue;
}
$remove_key = $remove_keys[0];
unset( $to_remove[ $remove_key ] );
unset( $to_add[ $add_key ] );
}
// `delete_metadata` removes _all_ instances of the value, so only call
// once.
$to_remove = array_unique( $to_remove );
foreach ( $to_remove as $value ) {
if ( ! delete_metadata( $this->get_meta_type(), $object_id, wp_slash( $name ), wp_slash( $value ) ) ) {
return new WP_Error(
'rest_meta_database_error',
__( 'Could not update meta value in database.' ),
array( 'key' => $name, 'status' => WP_Http::INTERNAL_SERVER_ERROR )
);
}
}
foreach ( $to_add as $value ) {
if ( ! add_metadata( $this->get_meta_type(), $object_id, wp_slash( $name ), wp_slash( $value ) ) ) {
return new WP_Error(
'rest_meta_database_error',
__( 'Could not update meta value in database.' ),
array( 'key' => $name, 'status' => WP_Http::INTERNAL_SERVER_ERROR )
);
}
}
return true;
}
/**
* Update meta value for an object.
*
* @param int $object_id Object ID to update.
* @param string $name Key for the custom field.
* @param mixed $value Updated value.
* @return bool|WP_Error True if meta field is updated, error otherwise.
*/
protected function update_meta_value( $object_id, $name, $value ) {
if ( ! current_user_can( 'edit_post_meta', $object_id, $name ) ) {
return new WP_Error(
'rest_cannot_update',
sprintf( __( 'You do not have permission to edit the %s custom field.' ), $name ),
array( 'key' => $name, 'status' => rest_authorization_required_code() )
);
}
$meta_type = $this->get_meta_type();
$meta_key = wp_slash( $name );
$meta_value = wp_slash( $value );
// Do the exact same check for a duplicate value as in update_metadata() to avoid update_metadata() returning false.
$old_value = get_metadata( $meta_type, $object_id, $meta_key );
if ( 1 === count( $old_value ) ) {
if ( $old_value[0] === $meta_value ) {
return true;
}
}
if ( ! update_metadata( $meta_type, $object_id, $meta_key, $meta_value ) ) {
return new WP_Error(
'rest_meta_database_error',
__( 'Could not update meta value in database.' ),
array( 'key' => $name, 'status' => WP_Http::INTERNAL_SERVER_ERROR )
);
}
return true;
}
/**
* Get all the registered meta fields.
*
* @return array
*/
protected function get_registered_fields() {
$registered = array();
foreach ( get_registered_meta_keys( $this->get_meta_type() ) as $name => $args ) {
if ( empty( $args['show_in_rest'] ) ) {
continue;
}
$rest_args = array();
if ( is_array( $args['show_in_rest'] ) ) {
$rest_args = $args['show_in_rest'];
}
$default_args = array(
'name' => $name,
'single' => $args['single'],
'schema' => array(),
'prepare_callback' => array( $this, 'prepare_value' ),
);
$default_schema = array(
'type' => null,
'description' => empty( $args['description'] ) ? '' : $args['description'],
'default' => isset( $args['default'] ) ? $args['default'] : null,
);
$rest_args = array_merge( $default_args, $rest_args );
$rest_args['schema'] = array_merge( $default_schema, $rest_args['schema'] );
if ( empty( $rest_args['schema']['type'] ) ) {
// Skip over meta fields that don't have a defined type.
if ( empty( $args['type'] ) ) {
continue;
}
if ( $rest_args['single'] ) {
$rest_args['schema']['type'] = $args['type'];
} else {
$rest_args['schema']['type'] = 'array';
$rest_args['schema']['items'] = array(
'type' => $args['type'],
);
}
}
$registered[ $rest_args['name'] ] = $rest_args;
} // End foreach().
return $registered;
}
/**
* Get the object's `meta` schema, conforming to JSON Schema.
*
* @return array
*/
public function get_field_schema() {
$fields = $this->get_registered_fields();
$schema = array(
'description' => __( 'Meta fields.' ),
'type' => 'object',
'context' => array( 'view', 'edit' ),
'properties' => array(),
);
foreach ( $fields as $key => $args ) {
$schema['properties'][ $key ] = $args['schema'];
}
return $schema;
}
/**
* Prepare a meta value for output.
*
* Default preparation for meta fields. Override by passing the
* `prepare_callback` in your `show_in_rest` options.
*
* @param mixed $value Meta value from the database.
* @param WP_REST_Request $request Request object.
* @param array $args REST-specific options for the meta key.
* @return mixed Value prepared for output.
*/
public static function prepare_value( $value, $request, $args ) {
$type = $args['schema']['type'];
// For multi-value fields, check the item type instead.
if ( 'array' === $type && ! empty( $args['schema']['items']['type'] ) ) {
$type = $args['schema']['items']['type'];
}
switch ( $type ) {
case 'string':
$value = (string) $value;
break;
case 'number':
$value = (float) $value;
break;
case 'boolean':
$value = (bool) $value;
break;
}
// Don't allow objects to be output.
if ( is_object( $value ) && ! ( $value instanceof JsonSerializable ) ) {
return null;
}
return $value;
}
}