wp_get_nocache_headers(): array

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

array

The associative array of header names and field values.

Performance profile

How much work a call to wp_get_nocache_headers() 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

Trivial

Touches nothing outside its own arguments.

Scaling

Constant

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

Instructions

16–26

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 27.

Plugin surface

1 hook

Third-party callbacks on 'nocache_headers' run inside this call, and their cost is not bounded by anything here.

Called by

3

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

What it touches

• hookthird-party callbacksapply_filters()called directly

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

What one call costs · 4 distinct outcomes

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

Hooks and filters fired · 1

One hook fires while wp_get_nocache_headers() runs, in this order:

1. 1
   apply_filters( nocache_headers )filterline 1514 (+20 into the body)

   Filters the cache-controlling HTTP headers that are used to prevent caching.

Uses · 2

• is_user_logged_in()Determines whether the current visitor is a logged in user.
• apply_filters()Calls the callback functions that have been added to a filter hook.

Used by · 3

• WP::send_headers()Sends additional HTTP headers for caching, content type, etc.
• WP_REST_Server::serve_request()Handles serving a REST API request.
• nocache_headers()Sets the HTTP headers to prevent caching for the different browsers.

Source code

View on Trac ↗View on GitHub ↗

1494function wp_get_nocache_headers() {1495	$cache_control = ( function_exists( 'is_user_logged_in' ) && is_user_logged_in() )1496		? 'no-cache, must-revalidate, max-age=0, no-store, private'1497		: 'no-cache, must-revalidate, max-age=0';1498 1499	$headers = array(1500		'Expires'       => 'Wed, 11 Jan 1984 05:00:00 GMT',1501		'Cache-Control' => $cache_control,1502	);1503 1504	if ( function_exists( 'apply_filters' ) ) {1505		/**1506		 * Filters the cache-controlling HTTP headers that are used to prevent caching.1507		 *1508		 * @since 2.8.01509		 *1510		 * @see wp_get_nocache_headers()1511		 *1512		 * @param array $headers Header names and field values.1513		 */1514		$headers = (array) apply_filters( 'nocache_headers', $headers );1515	}1516	$headers['Last-Modified'] = false;1517	return $headers;1518}

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 6.7.7 tag, from src/wp-includes/functions.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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