wppaste
WordPress

iis7_rewrite_rule_exists( string $filename ): bool

Since
2.8.0
Source
wp-admin/includes/misc.php:826
Checks if rewrite rule for WordPress already exists in the IIS 7+ configuration file.

Compatibility

WordPress
since 2.8.0
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.

Parameters

$filenamestring
The file path to the configuration file.

Return value

bool
Whether the rule exists.

Performance profile

How much work a call to iis7_rewrite_rule_exists() 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
6–27

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 31.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

  • filesystemfilesystem accessfile_exists()called directly
  • sqldatabase query->query()called directly

What one call costs · 3 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost iis7_rewrite_rule_exists() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
always6–8file_exists()
file_exists()16file_exists(), ->load()
file_exists()27file_exists(), ->load(), ->query()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev316–274
8.5316–274
8.4316–2743 fewer instructions than PHP 8.3
8.3346–304
8.2346–304
8.1346–304
7.4346–304

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 · 2

  • DOMDocument::__construct()
  • DOMXPath::__construct()

Source code

function iis7_rewrite_rule_exists( $filename ) {	if ( ! file_exists( $filename ) ) {		return false;	} 	if ( ! class_exists( 'DOMDocument', false ) ) {		return false;	} 	$doc = new DOMDocument(); 	if ( $doc->load( $filename ) === false ) {		return false;	} 	$xpath = new DOMXPath( $doc );	$rules = $xpath->query( '/configuration/system.webServer/rewrite/rules/rule[starts-with(@name,\'wordpress\')] | /configuration/system.webServer/rewrite/rules/rule[starts-with(@name,\'WordPress\')]' ); 	if ( 0 === $rules->length ) {		return false;	} 	return true;}

Changelog

Introduced in 2.8.0. 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/misc.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
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