save_mod_rewrite_rules(): bool|null

Description

Compatibility

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|null

True on write success, false on failure. Null in multisite.

Performance profile

How much work a call to save_mod_rewrite_rules() 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

Heavy

Reads or writes the filesystem via file_exists().

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

5–43

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 45.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

2

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

What it touches

• filesystemfilesystem accessfile_exists()called directly
• optionoption read or writeget_option()one call below save_mod_rewrite_rules()
• hookthird-party callbacksapply_filters()one call below save_mod_rewrite_rules()

Further down the call graph this can also reach cache, serialize, query and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 12 distinct outcomes

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

Uses · 4

• is_multisite()Determines whether Multisite is enabled.
• get_home_path()Gets the absolute filesystem path to the root of the WordPress installation.
• got_mod_rewrite()Returns whether the server is running Apache with the mod_rewrite module loaded.
• insert_with_markers()Inserts an array of strings into a file (.htaccess), placing it between BEGIN and END markers.

Used by · 2

• WP_Rewrite::flush_rules()Removes rewrite rules and then recreate rewrite rules.
• upgrade_560()Executes changes made in WordPress 5.6.0.

Source code

View on Trac ↗View on GitHub ↗

262function save_mod_rewrite_rules() {263	global $wp_rewrite;264 265	if ( is_multisite() ) {266		return null;267	}268 269	// Ensure get_home_path() is declared.270	require_once ABSPATH . 'wp-admin/includes/file.php';271 272	$home_path     = get_home_path();273	$htaccess_file = $home_path . '.htaccess';274 275	/*276	 * If the file doesn't already exist check for write access to the directory277	 * and whether we have some rules. Else check for write access to the file.278	 */279	if ( ! file_exists( $htaccess_file ) && is_writable( $home_path ) && $wp_rewrite->using_mod_rewrite_permalinks()280		|| is_writable( $htaccess_file )281	) {282		if ( got_mod_rewrite() ) {283			$rules = explode( "\n", $wp_rewrite->mod_rewrite_rules() );284 285			return insert_with_markers( $htaccess_file, 'WordPress', $rules );286		}287	}288 289	return false;290}

Changelog

Introduced in 1.5.0. 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 6.9.7 tag, from src/wp-admin/includes/misc.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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