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WordPress

wp_install_maybe_enable_pretty_permalinks(): bool

Since
4.2.0
Source
wp-admin/includes/upgrade.php:496
Maybe enable pretty permalinks on installation.

Description

If after enabling pretty permalinks don't work, fallback to query-string permalinks.

Compatibility

WordPress
since 4.2.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Return value

bool
Whether pretty permalinks are enabled. False otherwise.

Performance profile

How much work a call to wp_install_maybe_enable_pretty_permalinks() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Expensive

Reaches an outbound HTTP request via wp_remote_get().

Scaling
Scales with input

The body loops, so the work grows with how much data it finds.

Instructions
6–54

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 63.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
1

1 place in core call this, so the cost is paid more often than your own code shows.

What it touches

  • optionoption read or writeget_option()called directly
  • httpoutbound HTTP requestwp_remote_get()called directly
  • hookthird-party callbacksapply_filters()one call below wp_install_maybe_enable_pretty_permalinks()
  • cacheobject cachewp_cache_get()one call below wp_install_maybe_enable_pretty_permalinks()
  • serializeserialisationmaybe_unserialize()one call below wp_install_maybe_enable_pretty_permalinks()
  • querycontent queryget_post()one call below wp_install_maybe_enable_pretty_permalinks()

Further down the call graph this can also reach transient. That is the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 6 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_install_maybe_enable_pretty_permalinks() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
get_option()6get_option()
!get_option()14–15get_option(), ->set_permalink_structure(), ->flush_rules()
!get_option()44get_option(), ->set_permalink_structure(), ->flush_rules(), _x(), sanitize_title(), get_page_by_path(), wp_remote_get(), wp_remote_retrieve_header()
!get_option()48get_option(), ->set_permalink_structure(), ->flush_rules(), _x(), sanitize_title(), get_page_by_path(), wp_remote_get(), wp_remote_retrieve_header(), get_bloginfo()
!get_option()50get_option(), ->set_permalink_structure(), ->flush_rules(), _x(), sanitize_title(), get_page_by_path(), get_permalink(), wp_remote_get(), wp_remote_retrieve_header()
!get_option()54get_option(), ->set_permalink_structure(), ->flush_rules(), _x(), sanitize_title(), get_page_by_path(), get_permalink(), wp_remote_get(), wp_remote_retrieve_header(), get_bloginfo()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 63 instructions, 6–54 executed per call, 6 branches. The work does not change between versions.

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 8

Used by · 1

Source code

View on Trac View on GitHub 

function wp_install_maybe_enable_pretty_permalinks() {	global $wp_rewrite; 	// Bail if a permalink structure is already enabled.	if ( get_option( 'permalink_structure' ) ) {		return true;	} 	/*	 * The Permalink structures to attempt.	 *	 * The first is designed for mod_rewrite or nginx rewriting.	 *	 * The second is PATHINFO-based permalinks for web server configurations	 * without a true rewrite module enabled.	 */	$permalink_structures = array(		'/%year%/%monthnum%/%day%/%postname%/',		'/index.php/%year%/%monthnum%/%day%/%postname%/',	); 	foreach ( (array) $permalink_structures as $permalink_structure ) {		$wp_rewrite->set_permalink_structure( $permalink_structure ); 		/*		 * Flush rules with the hard option to force refresh of the web-server's		 * rewrite config file (e.g. .htaccess or web.config).		 */		$wp_rewrite->flush_rules( true ); 		$test_url = ''; 		// Test against a real WordPress post.		$first_post = get_page_by_path( sanitize_title( _x( 'hello-world', 'Default post slug' ) ), OBJECT, 'post' );		if ( $first_post ) {			$test_url = get_permalink( $first_post->ID );		} 		/*		 * Send a request to the site, and check whether		 * the 'X-Pingback' header is returned as expected.		 *		 * Uses wp_remote_get() instead of wp_remote_head() because web servers		 * can block head requests.		 */		$response          = wp_remote_get( $test_url, array( 'timeout' => 5 ) );		$x_pingback_header = wp_remote_retrieve_header( $response, 'X-Pingback' );		$pretty_permalinks = $x_pingback_header && get_bloginfo( 'pingback_url' ) === $x_pingback_header; 		if ( $pretty_permalinks ) {			return true;		}	} 	/*	 * If it makes it this far, pretty permalinks failed.	 * Fallback to query-string permalinks.	 */	$wp_rewrite->set_permalink_structure( '' );	$wp_rewrite->flush_rules( true ); 	return false;}

Changelog

Introduced in 4.2.0. Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 7.1.0 tag, from src/wp-admin/includes/upgrade.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
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