WP_REST_Server::serve_request( string|null $path = null ): null|false

Description

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$pathstring|nulloptional

The request route. If not set, $_SERVER['PATH_INFO'] will be used.
Default null.Default: null

Return value

null|false

Null if not served and a HEAD request, false otherwise.

Performance profile

How much work a call to WP_REST_Server::serve_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

Heavy

Reads stored settings via get_option(), cached per request but not free on a cold cache.

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

196–309

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 386.

Plugin surface

8 hooks

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

Called by

0

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

What it touches

• hookthird-party callbacksapply_filters()called directly
• optionoption read or writeget_option()called directly
• cacheobject cachewp_cache_get()one call below WP_REST_Server::serve_request()
• serializeserialisationmaybe_unserialize()one call below WP_REST_Server::serve_request()

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 · 384 distinct outcomes

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

This body has more branch combinations than are worth enumerating, so the table covers the outcomes found first rather than every one that exists.

Hooks and filters fired · 8

8 hooks fire while WP_REST_Server::serve_request() runs, in this order:

1. 1
   apply_filters( rest_jsonp_enabled )filterline 316 (+31 into the body)

   Filters whether JSONP is enabled for the REST API.

2. 2
   do_action( rest_enabled )filter_deprecatedline 348 (+63 into the body)

   Filters whether the REST API is enabled.

3. 3
   apply_filters( rest_exposed_cors_headers )filterline 412 (+127 into the body)

   Filters the list of response headers that are exposed to REST API CORS requests.

4. 4
   apply_filters( rest_allowed_cors_headers )filterline 438 (+153 into the body)

   Filters the list of request headers that are allowed for REST API CORS requests.

5. 5
   apply_filters( rest_post_dispatch )filterline 468 (+183 into the body)

   Filters the REST API response.

6. 6
   apply_filters( rest_send_nocache_headers )filterline 491 (+206 into the body)

   Filters whether to send no-cache headers on a REST API request.

7. 7
   apply_filters( rest_pre_serve_request )filterline 521 (+236 into the body)

   Filters whether the REST API request has already been served.

8. 8
   apply_filters( rest_pre_echo_response )filterline 544 (+259 into the body)

   Filters the REST API response.

Uses · 32

• apply_filters()Calls the callback functions that have been added to a filter hook.
• get_option()Retrieves an option value based on an option name.
• get_rest_url()Retrieves the URL to a REST endpoint on a site.
• sanitize_url()Sanitizes a URL for database or redirect usage.
• apply_filters_deprecated()Fires functions attached to a deprecated filter hook.
• __()Retrieves the translation of $text.
• wp_check_jsonp_callback()Checks that a JSONP callback is a valid JavaScript callback name.
• wp_unslash()Removes slashes from a string or recursively removes slashes from strings within an array.
• is_wp_error()Checks whether the given variable is a WordPress Error.
• rest_ensure_response()Ensures a REST response is a response object (for consistency).
• rest_parse_embed_param()Parses the "_embed" parameter into the list of resources to embed.
• is_user_logged_in()Determines whether the current visitor is a logged in user.

Source code

View on Trac ↗View on GitHub ↗

285	public function serve_request( $path = null ) {286		// Refuse to start a fresh top-level REST cycle while another dispatch287		// is already in flight. Internal sub-requests must use dispatch().288		if ( $this->is_dispatching() ) {289			return false;290		}291 292		/* @var WP_User|null $current_user */293		global $current_user;294 295		if ( $current_user instanceof WP_User && ! $current_user->exists() ) {296			/*297			 * If there is no current user authenticated via other means, clear298			 * the cached lack of user, so that an authenticate check can set it299			 * properly.300			 *301			 * This is done because for authentications such as Application302			 * Passwords, we don't want it to be accepted unless the current HTTP303			 * request is a REST API request, which can't always be identified early304			 * enough in evaluation.305			 */306			$current_user = null;307		}308 309		/**310		 * Filters whether JSONP is enabled for the REST API.311		 *312		 * @since 4.4.0313		 *314		 * @param bool $jsonp_enabled Whether JSONP is enabled. Default true.315		 */316		$jsonp_enabled = apply_filters( 'rest_jsonp_enabled', true );317 318		$jsonp_callback = false;319		if ( isset( $_GET['_jsonp'] ) ) {320			$jsonp_callback = $_GET['_jsonp'];321		}322 323		$content_type = ( $jsonp_callback && $jsonp_enabled ) ? 'application/javascript' : 'application/json';324		$this->send_header( 'Content-Type', $content_type . '; charset=' . get_option( 'blog_charset' ) );325		$this->send_header( 'X-Robots-Tag', 'noindex' );326 327		$api_root = get_rest_url();328		if ( ! empty( $api_root ) ) {329			$this->send_header( 'Link', '<' . sanitize_url( $api_root ) . '>; rel="https://api.w.org/"' );330		}331 332		/*333		 * Mitigate possible JSONP Flash attacks.334		 *335		 * https://miki.it/blog/2014/7/8/abusing-jsonp-with-rosetta-flash/336		 */337		$this->send_header( 'X-Content-Type-Options', 'nosniff' );338 339		/**340		 * Filters whether the REST API is enabled.341		 *342		 * @since 4.4.0343		 * @deprecated 4.7.0 Use the {@see 'rest_authentication_errors'} filter to344		 *                   restrict access to the REST API.345		 *346		 * @param bool $rest_enabled Whether the REST API is enabled. Default true.347		 */348		apply_filters_deprecated(349			'rest_enabled',350			array( true ),351			'4.7.0',352			'rest_authentication_errors',353			sprintf(354				/* translators: %s: rest_authentication_errors */355				__( 'The REST API can no longer be completely disabled, the %s filter can be used to restrict access to the API, instead.' ),356				'rest_authentication_errors'357			)358		);359 360		if ( $jsonp_callback ) {361			if ( ! $jsonp_enabled ) {362				echo $this->json_error( 'rest_callback_disabled', __( 'JSONP support is disabled on this site.' ), 400 );363				return false;364			}

Changelog

Introduced in 4.4.0. One change between 6.7.7 and 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 6.9.7 tag, from src/wp-includes/rest-api/class-wp-rest-server.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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