Custom_Background::wp_set_background_image()
- Since
- 3.4.0
- Source
wp-admin/includes/class-custom-background.php:616
Compatibility
Deprecated in WordPress 3.5.0. Kept for back-compatibility; avoid it in new code.
- 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 Custom_Background::wp_set_background_image() 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
- Moderate
- Scaling
- Constant
- Instructions
- 85–95
- Plugin surface
- 1 hook
- Called by
- 0
Reads stored settings via get_option(), cached per request but not free on a cold cache.
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 95.
Third-party callbacks on 'image_size_names_choose' run inside this call, and their cost is not bounded by anything here.
Nothing in core calls this; the cost is only what you spend yourself.
What it touches
- hookthird-party callbacks
apply_filters()called directly - optionoption read or write
get_option()called directly - cacheobject cache
wp_cache_get()one call below Custom_Background::wp_set_background_image() - serializeserialisation
maybe_unserialize()one call below Custom_Background::wp_set_background_image()
Further down the call graph this can also reach 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 · 4 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost Custom_Background::wp_set_background_image() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
!$sizes | 85–88 | check_ajax_referer(), current_user_can(), exit(), absint(), __(), __(), __(), __(), thumbnail(), apply_filters(), get_option(), update_post_meta(), wp_get_attachment_image_src(), wp_get_attachment_image_src(), sanitize_url(), set_theme_mod(), sanitize_url(), set_theme_mod(), exit() |
current_user_can() && isset($value) && !$sizes | 86 | check_ajax_referer(), current_user_can(), absint(), __(), __(), __(), __(), thumbnail(), apply_filters(), get_option(), update_post_meta(), wp_get_attachment_image_src(), wp_get_attachment_image_src(), sanitize_url(), set_theme_mod(), sanitize_url(), set_theme_mod(), exit() |
$sizes | 92–95 | check_ajax_referer(), current_user_can(), exit(), absint(), __(), __(), __(), __(), thumbnail(), apply_filters(), esc_attr(), get_option(), update_post_meta(), wp_get_attachment_image_src(), wp_get_attachment_image_src(), sanitize_url(), set_theme_mod(), sanitize_url(), set_theme_mod(), exit() |
current_user_can() && isset($value) && $sizes | 93 | check_ajax_referer(), current_user_can(), absint(), __(), __(), __(), __(), thumbnail(), apply_filters(), esc_attr(), get_option(), update_post_meta(), wp_get_attachment_image_src(), wp_get_attachment_image_src(), sanitize_url(), set_theme_mod(), sanitize_url(), set_theme_mod(), exit() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 95 | 85–95 | 3 | |
| 8.5 | 95 | 85–95 | 3 | |
| 8.4 | 95 | 85–95 | 3 | Different branch profile from PHP 8.3 |
| 8.3 | 95 | 8–94 | 3 | |
| 8.2 | 95 | 8–94 | 3 | |
| 8.1 | 95 | 8–94 | 3 | |
| 7.4 | 95 | 8–94 | 3 |
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 Custom_Background::wp_set_background_image() runs, in this order:
- apply_filters( image_size_names_choose )filterline 627 (+11 into the body)
Filters the names and labels of the default image sizes.
Uses · 11
- check_ajax_referer()Verifies the Ajax request to prevent processing requests external of the blog.
- current_user_can()Returns whether the current user has the specified capability.
- absint()Converts a value to non-negative integer.
- apply_filters()Calls the callback functions that have been added to a filter hook.
- __()Retrieves the translation of $text.
- esc_attr()Escaping for HTML attributes.
- update_post_meta()Updates a post meta field based on the given post ID.
- get_option()Retrieves an option value based on an option name.
- wp_get_attachment_image_src()Retrieves an image to represent an attachment.
- set_theme_mod()Updates theme modification value for the active theme.
- sanitize_url()Sanitizes a URL for database or redirect usage.
Source code
public function wp_set_background_image() { check_ajax_referer( 'custom-background' ); if ( ! current_user_can( 'edit_theme_options' ) || ! isset( $_POST['attachment_id'] ) ) { exit; } $attachment_id = absint( $_POST['attachment_id'] ); $sizes = array_keys( /** This filter is documented in wp-admin/includes/media.php */ apply_filters( 'image_size_names_choose', array( 'thumbnail' => __( 'Thumbnail' ), 'medium' => __( 'Medium' ), 'large' => __( 'Large' ), 'full' => __( 'Full Size' ), ) ) ); $size = 'thumbnail'; if ( in_array( $_POST['size'], $sizes, true ) ) { $size = esc_attr( $_POST['size'] ); } update_post_meta( $attachment_id, '_wp_attachment_is_custom_background', get_option( 'stylesheet' ) ); $url = wp_get_attachment_image_src( $attachment_id, $size ); $thumbnail = wp_get_attachment_image_src( $attachment_id, 'thumbnail' ); set_theme_mod( 'background_image', sanitize_url( $url[0] ) ); set_theme_mod( 'background_image_thumb', sanitize_url( $thumbnail[0] ) ); exit; }Changelog
Introduced in 3.4.0. One change between 6.7.7 and 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
none to never.verified against sourceAbout this page
- Parsed data
- Generated from the wordpress-develop 7.0.4 tag, from
src/wp-admin/includes/class-custom-background.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
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