--- /dev/null
+<?php
+/**
+ * REST API: WP_REST_Meta_Fields class
+ *
+ * @package WordPress
+ * @subpackage REST_API
+ * @since 4.7.0
+ */
+
+/**
+ * Core class to manage meta values for an object via the REST API.
+ *
+ * @since 4.7.0
+ */
+abstract class WP_REST_Meta_Fields {
+
+ /**
+ * Retrieves the object meta type.
+ *
+ * @since 4.7.0
+ * @access protected
+ *
+ * @return string One of 'post', 'comment', 'term', 'user', or anything
+ * else supported by `_get_meta_table()`.
+ */
+ abstract protected function get_meta_type();
+
+ /**
+ * Retrieves the object type for register_rest_field().
+ *
+ * @since 4.7.0
+ * @access protected
+ *
+ * @return string The REST field type, such as post type name, taxonomy name, 'comment', or `user`.
+ */
+ abstract protected function get_rest_field_type();
+
+ /**
+ * Registers the meta field.
+ *
+ * @since 4.7.0
+ * @access public
+ *
+ * @see register_rest_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(),
+ ));
+ }
+
+ /**
+ * Retrieves the meta field value.
+ *
+ * @since 4.7.0
+ * @access public
+ *
+ * @param int $object_id Object ID to fetch meta for.
+ * @param WP_REST_Request $request Full details about the request.
+ * @return WP_Error|object Object containing the meta values by name, otherwise WP_Error object.
+ */
+ public function get_value( $object_id, $request ) {
+ $fields = $this->get_registered_fields();
+ $response = array();
+
+ foreach ( $fields as $meta_key => $args ) {
+ $name = $args['name'];
+ $all_values = get_metadata( $this->get_meta_type(), $object_id, $meta_key, 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 $response;
+ }
+
+ /**
+ * Prepares a meta value for a 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.
+ *
+ * @since 4.7.0
+ * @access protected
+ *
+ * @param mixed $value Meta 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;
+ }
+
+ /**
+ * Updates meta values.
+ *
+ * @since 4.7.0
+ * @access public
+ *
+ * @param array $meta Array of meta parsed from the request.
+ * @param int $object_id Object ID to fetch meta for.
+ * @return WP_Error|null WP_Error if one occurs, null on success.
+ */
+ public function update_value( $meta, $object_id ) {
+ $fields = $this->get_registered_fields();
+ foreach ( $fields as $meta_key => $args ) {
+ $name = $args['name'];
+ if ( ! array_key_exists( $name, $meta ) ) {
+ 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( $meta[ $name ] ) ) {
+ $result = $this->delete_meta_value( $object_id, $meta_key, $name );
+ if ( is_wp_error( $result ) ) {
+ return $result;
+ }
+ continue;
+ }
+
+ $is_valid = rest_validate_value_from_schema( $meta[ $name ], $args['schema'], 'meta.' . $name );
+ if ( is_wp_error( $is_valid ) ) {
+ $is_valid->add_data( array( 'status' => 400 ) );
+ return $is_valid;
+ }
+
+ $value = rest_sanitize_value_from_schema( $meta[ $name ], $args['schema'] );
+
+ if ( $args['single'] ) {
+ $result = $this->update_meta_value( $object_id, $meta_key, $name, $value );
+ } else {
+ $result = $this->update_multi_meta_value( $object_id, $meta_key, $name, $value );
+ }
+
+ if ( is_wp_error( $result ) ) {
+ return $result;
+ }
+ }
+
+ return null;
+ }
+
+ /**
+ * Deletes a meta value for an object.
+ *
+ * @since 4.7.0
+ * @access protected
+ *
+ * @param int $object_id Object ID the field belongs to.
+ * @param string $meta_key Key for the field.
+ * @param string $name Name for the field that is exposed in the REST API.
+ * @return bool|WP_Error True if meta field is deleted, WP_Error otherwise.
+ */
+ protected function delete_meta_value( $object_id, $meta_key, $name ) {
+ $meta_type = $this->get_meta_type();
+ if ( ! current_user_can( "delete_{$meta_type}_meta", $object_id, $meta_key ) ) {
+ return new WP_Error(
+ 'rest_cannot_delete',
+ /* translators: %s: custom field key */
+ sprintf( __( 'Sorry, you are not allowed to edit the %s custom field.' ), $name ),
+ array( 'key' => $name, 'status' => rest_authorization_required_code() )
+ );
+ }
+
+ if ( ! delete_metadata( $meta_type, $object_id, wp_slash( $meta_key ) ) ) {
+ 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;
+ }
+
+ /**
+ * Updates multiple meta values for an object.
+ *
+ * Alters the list of values in the database to match the list of provided values.
+ *
+ * @since 4.7.0
+ * @access protected
+ *
+ * @param int $object_id Object ID to update.
+ * @param string $meta_key Key for the custom field.
+ * @param string $name Name for the field that is exposed in the REST API.
+ * @param array $values List of values to update to.
+ * @return bool|WP_Error True if meta fields are updated, WP_Error otherwise.
+ */
+ protected function update_multi_meta_value( $object_id, $meta_key, $name, $values ) {
+ $meta_type = $this->get_meta_type();
+ if ( ! current_user_can( "edit_{$meta_type}_meta", $object_id, $meta_key ) ) {
+ return new WP_Error(
+ 'rest_cannot_update',
+ /* translators: %s: custom field key */
+ sprintf( __( 'Sorry, you are not allowed to edit the %s custom field.' ), $name ),
+ array( 'key' => $name, 'status' => rest_authorization_required_code() )
+ );
+ }
+
+ $current = get_metadata( $meta_type, $object_id, $meta_key, 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( $meta_type, $object_id, wp_slash( $meta_key ), 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( $meta_type, $object_id, wp_slash( $meta_key ), 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;
+ }
+
+ /**
+ * Updates a meta value for an object.
+ *
+ * @since 4.7.0
+ * @access protected
+ *
+ * @param int $object_id Object ID to update.
+ * @param string $meta_key Key for the custom field.
+ * @param string $name Name for the field that is exposed in the REST API.
+ * @param mixed $value Updated value.
+ * @return bool|WP_Error True if the meta field was updated, WP_Error otherwise.
+ */
+ protected function update_meta_value( $object_id, $meta_key, $name, $value ) {
+ $meta_type = $this->get_meta_type();
+ if ( ! current_user_can( "edit_{$meta_type}_meta", $object_id, $meta_key ) ) {
+ return new WP_Error(
+ 'rest_cannot_update',
+ /* translators: %s: custom field key */
+ sprintf( __( 'Sorry, you are not allowed to edit the %s custom field.' ), $name ),
+ array( 'key' => $name, 'status' => rest_authorization_required_code() )
+ );
+ }
+
+ $meta_key = wp_slash( $meta_key );
+ $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;
+ }
+
+ /**
+ * Retrieves all the registered meta fields.
+ *
+ * @since 4.7.0
+ * @access protected
+ *
+ * @return array Registered fields.
+ */
+ 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'],
+ 'type' => ! empty( $args['type'] ) ? $args['type'] : null,
+ 'schema' => array(),
+ 'prepare_callback' => array( $this, 'prepare_value' ),
+ );
+
+ $default_schema = array(
+ 'type' => $default_args['type'],
+ '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'] );
+
+ $type = ! empty( $rest_args['type'] ) ? $rest_args['type'] : null;
+ $type = ! empty( $rest_args['schema']['type'] ) ? $rest_args['schema']['type'] : $type;
+
+ if ( ! in_array( $type, array( 'string', 'boolean', 'integer', 'number' ) ) ) {
+ continue;
+ }
+
+ if ( empty( $rest_args['single'] ) ) {
+ $rest_args['schema']['items'] = array(
+ 'type' => $rest_args['type'],
+ );
+ $rest_args['schema']['type'] = 'array';
+ }
+
+ $registered[ $name ] = $rest_args;
+ }
+
+ return $registered;
+ }
+
+ /**
+ * Retrieves the object's meta schema, conforming to JSON Schema.
+ *
+ * @since 4.7.0
+ * @access protected
+ *
+ * @return array Field schema data.
+ */
+ public function get_field_schema() {
+ $fields = $this->get_registered_fields();
+
+ $schema = array(
+ 'description' => __( 'Meta fields.' ),
+ 'type' => 'object',
+ 'context' => array( 'view', 'edit' ),
+ 'properties' => array(),
+ 'arg_options' => array(
+ 'sanitize_callback' => null,
+ 'validate_callback' => array( $this, 'check_meta_is_array' ),
+ ),
+ );
+
+ foreach ( $fields as $args ) {
+ $schema['properties'][ $args['name'] ] = $args['schema'];
+ }
+
+ return $schema;
+ }
+
+ /**
+ * Prepares a meta value for output.
+ *
+ * Default preparation for meta fields. Override by passing the
+ * `prepare_callback` in your `show_in_rest` options.
+ *
+ * @since 4.7.0
+ * @access public
+ *
+ * @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. If a non-JsonSerializable object, null.
+ */
+ 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 'integer':
+ $value = (int) $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;
+ }
+
+ /**
+ * Check the 'meta' value of a request is an associative array.
+ *
+ * @since 4.7.0
+ * @access public
+ *
+ * @param mixed $value The meta value submitted in the request.
+ * @param WP_REST_Request $request Full details about the request.
+ * @param string $param The parameter name.
+ * @return WP_Error|string The meta array, if valid, otherwise an error.
+ */
+ public function check_meta_is_array( $value, $request, $param ) {
+ if ( ! is_array( $value ) ) {
+ return false;
+ }
+
+ return $value;
+ }
+}