Add user preference api

gutenberg.php

@@ -22,6 +22,8 @@
 	require_once dirname( __FILE__ ) . '/lib/i18n.php';
 	require_once dirname( __FILE__ ) . '/lib/parser.php';
 	require_once dirname( __FILE__ ) . '/lib/register.php';
+	require_once dirname( __FILE__ ) . '/lib/preferences.php';
+	require_once dirname( __FILE__ ) . '/lib/api.php';
 
 	// Register server-side code for individual blocks.
 	require_once dirname( __FILE__ ) . '/lib/blocks/latest-posts.php';

lib/api.php

@@ -0,0 +1,89 @@
+<?php
+/**
+ * API Endpoints.
+ *
+ * @package gutenberg
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	die( 'Silence is golden.' );
+}
+
+/**
+ * Validates that a preference name is valid, as part of a REST API request.
+ *
+ * @param  string           $preference_name Preference name.
+ * @param  WP_REST_Request  $request The REST request.
+ * @param  string           $request The parameter key for the value being validated.
+ * @return bool             If the preference name is valid.
+ */
+function gutenberg_validate_preference_name( $preference_name, $request, $key ) {
+	return Gutenberg_User_Preferences::is_valid_preference_name( $preference_name );
+}
+
+/**
+ * Callback for getting a specific user preference.
+ *
+ * @param  WP_REST_Request  $request The REST request.
+ * @return mixed            The value of the preference.
+ */
+function gutenburg_get_user_preference( $request ) {
+	$params = $request->get_url_params();
+	return Gutenberg_User_Preferences::get_preference( get_current_user_id(), $params['preference'] );
+}
+
+/**
+ * Callback for getting all preferences for a user.
+ *
+ * @param  WP_REST_Request  $request The REST request.
+ * @return array            Associative array of user preferences.
+ */
+function gutenburg_get_user_preferences( $request ) {
+	return Gutenberg_User_Preferences::get_preferences( get_current_user_id() );
+}
+
+/**
+ * Callback for setting a user preference.
+ *
+ * @param  WP_REST_Request  $request The REST request.
+ * @return bool             If the preference was set successfully.
+ */
+function gutenburg_set_user_preference( $request ) {
+	$params = $request->get_params();
+	return Gutenberg_User_Preferences::set_preference( get_current_user_id(), $params['preference'], $params['value'] );
+}
+
+/**
+ * Callback for registering gutenberg API routes.
+ *
+ * @return null
+ */
+function gutenburg_register_routes() {
+	register_rest_route( 'gutenburg/v1', '/user-preferences', array(
+		'methods'  => WP_REST_Server::READABLE,
+		'callback' => 'gutenburg_get_user_preferences',
+	) );
+	register_rest_route( 'gutenburg/v1', '/user-preferences/(?P<preference>[a-z_]+)', array(
+		'methods'  => WP_REST_Server::READABLE,
+		'callback' => 'gutenburg_get_user_preference',
+		'args'     => array(
+			'preference' => array(
+				'validate_callback' => 'gutenberg_validate_preference_name',
+			),
+		),
+	) );
+	register_rest_route( 'gutenburg/v1', '/user-preferences/(?P<preference>[a-z_]+)', array(
+		'methods'  => WP_REST_Server::EDITABLE,
+		'callback' => 'gutenburg_set_user_preference',
+		'args'     => array(
+			'value' => array(
+				'required' => true,
+			),
+			'preference' => array(
+				'validate_callback' => 'gutenberg_validate_preference_name',
+			),
+		),
+	) );
+}
+
+add_action( 'rest_api_init', 'gutenburg_register_routes' );

lib/preferences.php

@@ -0,0 +1,74 @@
+<?php
+/**
+ * Preference handling.
+ *
+ * @package gutenberg
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	die( 'Silence is golden.' );
+}
+
+/***
+ * User preference management.
+ */
+class Gutenberg_User_Preferences {
+	const VALID_PREFERENCES = array(
+		'block_usage',
+		'layout_config',
+	);
+
+	/**
+	 * Validates that a preference name is valid, as part of a REST API request.
+	 *
+	 * @param  string           $preference_name Preference name.
+	 * @return bool             If the preference name is valid preference.
+	 */
+	public static function is_valid_preference_name( $preference_name ) {
+		return in_array( $preference_name, self::VALID_PREFERENCES );
+	}
+
+	/**
+	 * Gets a single preference for a user.
+	 *
+	 * @param  int              $user_id User ID.
+	 * @param  string           $preference_name Preference name.
+	 * @return mixed            Stored preference value.
+	 */
+	public static function get_preference( $user_id, $preference_name ) {
+		if ( ! self::is_valid_preference_name( $preference_name ) ) {
+			return false;
+		}
+		return get_user_meta( $user_id, 'gutenburg_' . $preference_name );
+	}
+
+	/**
+	 * Gets all preferences for a user.
+	 *
+	 * @param  int              $user_id User ID.
+	 * @return mixed            Stored preference values indexed by preference name.
+	 */
+	public static function get_preferences( $user_id ) {
+		$preferences = array();
+		foreach ( self::VALID_PREFERENCES as $preference_name ) {
+			$preferences[ $preference_name ] = get_user_meta( $user_id, 'gutenburg_' . $preference_name );
+		}
+		return $preferences;
+	}
+
+	/**
+	 * Sets a single preference for a user.
+	 *
+	 * @param      int              $user_id User ID.
+	 * @param      string           $preference_name Preference name.
+	 * @param      mixed            Preference value to store.
+	 * @return     bool             If the store was successful.
+	 */
+	public static function set_preference( $user_id, $preference_name, $value ) {
+		if ( ! self::is_valid_preference_name( $preference_name ) ) {
+			return false;
+		}
+		update_user_meta( $user_id, 'gutenburg_' . $preference_name, $value );
+		return true;
+	}
+}