initial commit

includes/class-wc-rate-limiter.php

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+<?php
+/**
+ * Provide basic rate limiting functionality via WP Options API.
+ *
+ * Currently only provides a simple limit by delaying action by X seconds.
+ *
+ * Example usage:
+ *
+ * When an action runs, call set_rate_limit, e.g.:
+ *
+ * WC_Rate_Limiter::set_rate_limit( "{$my_action_name}_{$user_id}", $delay );
+ *
+ * This sets a timestamp for future timestamp after which action can run again.
+ *
+ *
+ * Then before running the action again, check if the action is allowed to run, e.g.:
+ *
+ * if ( WC_Rate_Limiter::retried_too_soon( "{$my_action_name}_{$user_id}" ) ) {
+ *     add_notice( 'Sorry, too soon!' );
+ * }
+ *
+ * @package WooCommerce\Classes
+ * @version 3.9.0
+ * @since   3.9.0
+ */
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * Rate limit class.
+ */
+class WC_Rate_Limiter {
+
+	/**
+	 * Constructs Option name from action identifier.
+	 *
+	 * @param string $action_id Identifier of the action.
+	 * @return string
+	 */
+	public static function storage_id( $action_id ) {
+		return 'woocommerce_rate_limit_' . $action_id;
+	}
+
+	/**
+	 * Returns true if the action is not allowed to be run by the rate limiter yet, false otherwise.
+	 *
+	 * @param string $action_id Identifier of the action.
+	 * @return bool
+	 */
+	public static function retried_too_soon( $action_id ) {
+		$next_try_allowed_at = get_option( self::storage_id( $action_id ) );
+
+		// No record of action running, so action is allowed to run.
+		if ( false === $next_try_allowed_at ) {
+			return false;
+		}
+
+		// Before the next run is allowed, retry forbidden.
+		if ( time() <= $next_try_allowed_at ) {
+			return true;
+		}
+
+		// After the next run is allowed, retry allowed.
+		return false;
+	}
+
+	/**
+	 * Sets the rate limit delay in seconds for action with identifier $id.
+	 *
+	 * @param string $action_id Identifier of the action.
+	 * @param int    $delay Delay in seconds.
+	 * @return bool True if the option setting was successful, false otherwise.
+	 */
+	public static function set_rate_limit( $action_id, $delay ) {
+		$option_name         = self::storage_id( $action_id );
+		$next_try_allowed_at = time() + $delay;
+		return update_option( $option_name, $next_try_allowed_at );
+	}
+}