WP_Customize_Manager::customize_preview_init()
- Since
- 3.4.0
- Source
wp-includes/class-wp-customize-manager.php:1906
Compatibility
- WordPress
- since 3.4.0
- 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.
Performance profile
How much work a call to WP_Customize_Manager::customize_preview_init() 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
- Scaling
- Constant
- Instructions
- 32–75
- Plugin surface
- 1 hook
- Called by
- 1
Touches nothing outside its own arguments.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 87.
Third-party callbacks on 'customize_preview_init' run inside this call, and their cost is not bounded by anything here.
1 place in core call this, so the cost is paid more often than your own code shows.
What it touches
- hookthird-party callbacks
do_action()called directly
Further down the call graph this can also reach query, option, cache, serialize 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 · 6 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost WP_Customize_Manager::customize_preview_init() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
headers_sent() && !current_user_can() | 32 | headers_sent(), add_filter(), current_user_can(), __(), sprintf(), ->wp_die() |
!headers_sent() && !current_user_can() | 40 | headers_sent(), nocache_headers(), header(), header(), add_filter(), current_user_can(), __(), sprintf(), ->wp_die() |
headers_sent() | 63 | headers_sent(), add_filter(), ->prepare_controls(), wp_enqueue_script(), wp_enqueue_style(), add_filter(), do_action() |
headers_sent() && current_user_can() | 67 | headers_sent(), add_filter(), current_user_can(), ->prepare_controls(), wp_enqueue_script(), wp_enqueue_style(), add_filter(), do_action() |
!headers_sent() | 71 | headers_sent(), nocache_headers(), header(), header(), add_filter(), ->prepare_controls(), wp_enqueue_script(), wp_enqueue_style(), add_filter(), do_action() |
!headers_sent() && current_user_can() | 75 | headers_sent(), nocache_headers(), header(), header(), add_filter(), current_user_can(), ->prepare_controls(), wp_enqueue_script(), wp_enqueue_style(), add_filter(), do_action() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 87 instructions, 32–75 executed per call, 3 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.
Hooks and filters fired · 1
One hook fires while WP_Customize_Manager::customize_preview_init() runs, in this order:
- do_action( customize_preview_init )actionline 1960 (+54 into the body)
Fires once the Customizer preview has initialized and JavaScript settings have been printed.
Uses · 10
- nocache_headers()Sets the HTTP headers to prevent caching for the different browsers.
- add_filter()Adds a callback function to a filter hook.
- current_user_can()Returns whether the current user has the specified capability.
- __()Retrieves the translation of $text.
- wp_enqueue_script()Enqueues a script.
- wp_enqueue_style()Enqueues a CSS stylesheet.
- add_action()Adds a callback function to an action hook.
- do_action()Calls the callback functions that have been added to an action hook.
- WP_Customize_Manager::wp_die()Custom wp_die wrapper. Returns either the standard message for UI or the Ajax message.
- WP_Customize_Manager::prepare_controls()Prepares panels, sections, and controls.
Used by · 1
- WP_Customize_Manager::wp_loaded()Registers styles/scripts and initialize the preview of each setting
Source code
public function customize_preview_init() { /* * Now that Customizer previews are loaded into iframes via GET requests * and natural URLs with transaction UUIDs added, we need to ensure that * the responses are never cached by proxies. In practice, this will not * be needed if the user is logged-in anyway. But if anonymous access is * allowed then the auth cookies would not be sent and WordPress would * not send no-cache headers by default. */ if ( ! headers_sent() ) { nocache_headers(); header( 'X-Robots: noindex, nofollow, noarchive' ); header( 'X-Robots-Tag: noindex, nofollow, noarchive' ); } add_filter( 'wp_robots', 'wp_robots_no_robots' ); add_filter( 'wp_headers', array( $this, 'filter_iframe_security_headers' ) ); /* * If preview is being served inside the customizer preview iframe, and * if the user doesn't have customize capability, then it is assumed * that the user's session has expired and they need to re-authenticate. */ if ( $this->messenger_channel && ! current_user_can( 'customize' ) ) { $this->wp_die( -1, sprintf( /* translators: %s: customize_messenger_channel */ __( 'Unauthorized. You may remove the %s param to preview as frontend.' ), '<code>customize_messenger_channel<code>' ) ); return; } $this->prepare_controls(); add_filter( 'wp_redirect', array( $this, 'add_state_query_params' ) ); wp_enqueue_script( 'customize-preview' ); wp_enqueue_style( 'customize-preview' ); add_action( 'wp_head', array( $this, 'customize_preview_loading_style' ) ); add_action( 'wp_head', array( $this, 'remove_frameless_preview_messenger_channel' ) ); add_action( 'wp_footer', array( $this, 'customize_preview_settings' ), 20 ); add_filter( 'get_edit_post_link', '__return_empty_string' ); /** * Fires once the Customizer preview has initialized and JavaScript * settings have been printed. * * @since 3.4.0 * * @param WP_Customize_Manager $manager WP_Customize_Manager instance. */ do_action( 'customize_preview_init', $this ); }Changelog
Introduced in 3.4.0. Unchanged from 6.7.7 through 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-includes/class-wp-customize-manager.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.