wp_is_serving_rest_request(): bool
- Since
- 6.5.0
- Source
wp-includes/functions.php:4862
Description
The function relies on the 'REST_REQUEST' global. As such, it only returns true when an actual REST request is being made. It does not return true when a REST endpoint is hit as part of another request, e.g. for preloading a REST response. See wp_is_rest_endpoint() for that purpose.
This function should not be called until the 'parse_request' action, as the constant is only defined then, even for an actual REST request.
Compatibility
- WordPress
- since 6.5.0
- 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.
Return value
bool- True if it's a WordPress REST API request, false otherwise.
Performance profile
How much work a call to wp_is_serving_rest_request() 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
- 3–5
- Plugin surface
- None
- Called by
- 8
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 5.
Nothing here hands control to plugin code.
8 places in core call this, so the cost is paid more often than your own code shows.
What one call costs · 1 distinct outcome
One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_is_serving_rest_request() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 3–5 | none |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 5 instructions, 3–5 executed per call, 1 branch. 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.
Used by · 8
- WP_Query::parse_query()Parses a query string and sets query type booleans.
- WP_REST_Attachments_Controller::create_item()Creates a single attachment.
- WP_REST_Attachments_Controller::edit_media_item()Applies edits to a media item and creates a new attachment record.
- render_block_core_tag_cloud()Renders the `core/tag-cloud` block on server.
- rest_api_default_filters()Registers the default REST API filters.
- wp_die()Kills WordPress execution and displays HTML page with an error message.
- wp_is_rest_endpoint()Checks whether a REST API endpoint request is currently being handled.
- wp_send_json()Sends a JSON response back to an Ajax request.
Source code
function wp_is_serving_rest_request() { return defined( 'REST_REQUEST' ) && REST_REQUEST;}Changelog
Introduced in 6.5.0. 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 7.1.0 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
- Something wrong on this page? Report it and it gets fixed in the next regeneration.