get_rest_url( int|null $blog_id = null, string $path = '/', string $scheme = 'rest' ): string

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

$blog_idint|nulloptional

Blog ID. Default of null returns URL for current blog.Default: null

$pathstringoptional

REST route. Default '/'.Default: '/'

$schemestringoptional

Sanitization scheme. Default 'rest'.Default: 'rest'

Return value

string

Full URL to the endpoint.

Performance profile

How much work a call to get_rest_url() 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

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

Scaling

Constant

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

Instructions

46–86

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 112.

Plugin surface

1 hook

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

Called by

8

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

What it touches

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

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 · 45 distinct outcomes

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

Hooks and filters fired · 1

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

1. 1
   apply_filters( rest_url )filterline 577 (+58 into the body)

   Filters the REST URL.

Uses · 13

• is_multisite()Determines whether Multisite is enabled.
• get_blog_option()Retrieves option value for a given blog id based on name of option.
• get_option()Retrieves an option value based on an option name.
• get_home_url()Retrieves the URL for a given site where the front end is accessible.
• rest_get_url_prefix()Retrieves the URL prefix for any API resource.
• trailingslashit()Appends a trailing slash.
• str_ends_with()Polyfill for `str_ends_with()` function added in PHP 8.0.
• add_query_arg()Retrieves a modified URL query string.
• is_ssl()Determines if SSL is used.
• set_url_scheme()Sets the scheme for a URL.
• is_admin()Determines whether the current request is for an administrative interface page.
• force_ssl_admin()Determines whether to force SSL used for the Administration Screens.

Used by · 8

• WP_REST_Server::serve_request()Handles serving a REST API request.
• rest_output_link_header()Sends a Link header for the REST API.
• rest_output_link_wp_head()Outputs the REST API link tag into page header.
• rest_output_rsd()Adds the REST API URL to the WP RSD endpoint.
• rest_url()Retrieves the URL to a REST endpoint.
• wp_default_packages_inline_scripts()Adds inline scripts required for the WordPress JavaScript packages.
• wp_default_scripts()Registers all WordPress scripts.
• wp_is_local_html_output()Checks whether a given HTML string is likely an output from this WordPress site.

Source code

View on Trac ↗View on GitHub ↗

519function get_rest_url( $blog_id = null, $path = '/', $scheme = 'rest' ) {520	if ( empty( $path ) ) {521		$path = '/';522	}523 524	$path = '/' . ltrim( $path, '/' );525 526	if ( is_multisite() && get_blog_option( $blog_id, 'permalink_structure' ) || get_option( 'permalink_structure' ) ) {527		global $wp_rewrite;528 529		if ( $wp_rewrite->using_index_permalinks() ) {530			$url = get_home_url( $blog_id, $wp_rewrite->index . '/' . rest_get_url_prefix(), $scheme );531		} else {532			$url = get_home_url( $blog_id, rest_get_url_prefix(), $scheme );533		}534 535		$url .= $path;536	} else {537		$url = trailingslashit( get_home_url( $blog_id, '', $scheme ) );538		/*539		 * nginx only allows HTTP/1.0 methods when redirecting from / to /index.php.540		 * To work around this, we manually add index.php to the URL, avoiding the redirect.541		 */542		if ( ! str_ends_with( $url, 'index.php' ) ) {543			$url .= 'index.php';544		}545 546		$url = add_query_arg( 'rest_route', $path, $url );547	}548 549	if ( is_ssl() && isset( $_SERVER['SERVER_NAME'] ) ) {550		// If the current host is the same as the REST URL host, force the REST URL scheme to HTTPS.551		if ( parse_url( get_home_url( $blog_id ), PHP_URL_HOST ) === $_SERVER['SERVER_NAME'] ) {552			$url = set_url_scheme( $url, 'https' );553		}554	}555 556	if ( is_admin() && force_ssl_admin() ) {557		/*558		 * In this situation the home URL may be http:, and `is_ssl()` may be false,559		 * but the admin is served over https: (one way or another), so REST API usage560		 * will be blocked by browsers unless it is also served over HTTPS.561		 */562		$url = set_url_scheme( $url, 'https' );563	}564 565	/**566	 * Filters the REST URL.567	 *568	 * Use this filter to adjust the url returned by the get_rest_url() function.569	 *570	 * @since 4.4.0571	 *572	 * @param string   $url     REST URL.573	 * @param string   $path    REST route.574	 * @param int|null $blog_id Blog ID.575	 * @param string   $scheme  Sanitization scheme.576	 */577	return apply_filters( 'rest_url', $url, $path, $blog_id, $scheme );578}

Changelog

Introduced in 4.4.0. 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 7.0.4 tag, from src/wp-includes/rest-api.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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