WP_Rewrite::flush_rules() – Method | Developer.WordPress.org

Removes rewrite rules and then recreate rewrite rules.

Description

Calls WP_Rewrite::wp_rewrite_rules() after removing the ‘rewrite_rules’ option.
If the function named ‘save_mod_rewrite_rules’ exists, it will be called.

Parameters

$hardbooloptional: Whether to update .htaccess (hard flush) or just update rewrite_rules option (soft flush). Default is true (hard).
Default:true

More Information

This method can be used to refresh WordPress’ rewrite rule cache. Generally, this should be used after programmatically adding one or more custom rewrite rules.

Because this function can be extremely costly in terms of performance, it should be used as sparingly as possible – such as during activation or deactivation of plugins or themes. Every attempt should be made to avoid using it in hooks that execute on each page load, such as init.

What it does

WordPress keeps a cache of all custom rewrite rules. Sometimes plugins or themes make modifications to those rules, however WordPress will not actually recognize the changes until the cache is regenerated.

This is not a procedural function, but a non-static method of the WP_Rewrite class. To call flush_rules(), you must first ensure you are using WordPress’ $wp_rewrite global, and call it as a method (see “Usage” above for an example).

Note: This same method is called whenever permalink settings are changed or saved in the WordPress admin, so rewrite rules can be manually refreshed by visiting the Settings > Permalinks screen in WordPress’s admin.

WARNING: If this function is called without a parameter or with a parameter of true, your .htaccess will be overwritten and any custom rules will be lost!

Source

public function flush_rules( $hard = true ) {
	static $do_hard_later = null;

	// Prevent this action from running before everyone has registered their rewrites.
	if ( ! did_action( 'wp_loaded' ) ) {
		add_action( 'wp_loaded', array( $this, 'flush_rules' ) );
		$do_hard_later = ( isset( $do_hard_later ) ) ? $do_hard_later || $hard : $hard;
		return;
	}

	if ( isset( $do_hard_later ) ) {
		$hard = $do_hard_later;
		unset( $do_hard_later );
	}

	$this->refresh_rewrite_rules();

	/**
	 * Filters whether a "hard" rewrite rule flush should be performed when requested.
	 *
	 * A "hard" flush updates .htaccess (Apache) or web.config (IIS).
	 *
	 * @since 3.7.0
	 *
	 * @param bool $hard Whether to flush rewrite rules "hard". Default true.
	 */
	if ( ! $hard || ! apply_filters( 'flush_rewrite_rules_hard', true ) ) {
		return;
	}
	if ( function_exists( 'save_mod_rewrite_rules' ) ) {
		save_mod_rewrite_rules();
	}
	if ( function_exists( 'iis7_save_url_rewrite_rules' ) ) {
		iis7_save_url_rewrite_rules();
	}
}

View all references View on Trac View on GitHub

Hooks

apply_filters( ‘flush_rewrite_rules_hard’, bool $hard ): Filters whether a “hard” rewrite rule flush should be performed when requested.

Uses	Description
WP_Rewrite::refresh_rewrite_rules()`wp-includes/class-wp-rewrite.php`	Refreshes the rewrite rules, saving the fresh value to the database.
save_mod_rewrite_rules()`wp-admin/includes/misc.php`	Updates the htaccess file with the current rules if it is writable.
iis7_save_url_rewrite_rules()`wp-admin/includes/misc.php`	Updates the IIS web.config file with the current rules if it is writable.
did_action()`wp-includes/plugin.php`	Retrieves the number of times an action has been fired during the current request.
add_action()`wp-includes/plugin.php`	Adds a callback function to an action hook.
apply_filters()`wp-includes/plugin.php`	Calls the callback functions that have been added to a filter hook.

Show 2 more Show less

Used by	Description
wp_install_maybe_enable_pretty_permalinks()`wp-admin/includes/upgrade.php`	Maybe enable pretty permalinks on installation.
wp_install_defaults()`wp-admin/includes/upgrade.php`	Creates the initial content for a newly-installed site.
flush_rewrite_rules()`wp-includes/rewrite.php`	Removes rewrite rules and then recreate rewrite rules.

Changelog

Version	Description
2.0.1	Introduced.

WP_Rewrite::flush_rules( bool $hard = true )

In this article