WP_REST_URL_Details_Controller::get_remote_url( string $url ): string|WP_Error

Compatibility

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

Parameters

$urlstring

The website URL whose HTML to access.

Return value

string|WP_Error

The HTTP response from the remote URL on success.
WP_Error if no response or no content.

Performance profile

How much work a call to WP_REST_URL_Details_Controller::get_remote_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

Expensive

Reaches an outbound HTTP request via wp_safe_remote_get().

Scaling

Constant

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

Instructions

40–50

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 62.

Plugin surface

1 hook

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

Called by

1

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

What it touches

• hookthird-party callbacksapply_filters()called directly
• httpoutbound HTTP requestwp_safe_remote_get()called directly
• optionoption read or writeget_option()one call below WP_REST_URL_Details_Controller::get_remote_url()

Further down the call graph this can also reach cache, serialize, 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 · 3 distinct outcomes

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

Hooks and filters fired · 1

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

1. 1
   apply_filters( rest_url_details_http_request_args )filterline 252 (+28 into the body)

   Filters the HTTP request args for URL data retrieval.

Uses · 7

• get_bloginfo()Retrieves information about the current site.
• apply_filters()Calls the callback functions that have been added to a filter hook.
• wp_safe_remote_get()Retrieves the raw response from a safe HTTP request using the GET method.
• wp_remote_retrieve_response_code()Retrieves only the response code from the raw response.
• __()Retrieves the translation of $text.
• wp_remote_retrieve_body()Retrieves only the body from the raw response.
• WP_Error::__construct()Initializes the error.

Used by · 1

• WP_REST_URL_Details_Controller::parse_url_details()Retrieves the contents of the title tag from the HTML response.

Source code

View on Trac ↗View on GitHub ↗

224	private function get_remote_url( $url ) {225 226		/*227		 * Provide a modified UA string to workaround web properties which block WordPress "Pingbacks".228		 * Why? The UA string used for pingback requests contains `WordPress/` which is very similar229		 * to that used as the default UA string by the WP HTTP API. Therefore requests from this230		 * REST endpoint are being unintentionally blocked as they are misidentified as pingback requests.231		 * By slightly modifying the UA string, but still retaining the "WordPress" identification (via "WP")232		 * we are able to work around this issue.233		 * Example UA string: `WP-URLDetails/5.9-alpha-51389 (+http://localhost:8888)`.234		*/235		$modified_user_agent = 'WP-URLDetails/' . get_bloginfo( 'version' ) . ' (+' . get_bloginfo( 'url' ) . ')';236 237		$args = array(238			'limit_response_size' => 150 * KB_IN_BYTES,239			'user-agent'          => $modified_user_agent,240		);241 242		/**243		 * Filters the HTTP request args for URL data retrieval.244		 *245		 * Can be used to adjust response size limit and other WP_Http::request() args.246		 *247		 * @since 5.9.0248		 *249		 * @param array  $args Arguments used for the HTTP request.250		 * @param string $url  The attempted URL.251		 */252		$args = apply_filters( 'rest_url_details_http_request_args', $args, $url );253 254		$response = wp_safe_remote_get( $url, $args );255 256		if ( WP_Http::OK !== wp_remote_retrieve_response_code( $response ) ) {257			// Not saving the error response to cache since the error might be temporary.258			return new WP_Error(259				'no_response',260				__( 'URL not found. Response returned a non-200 status code for this URL.' ),261				array( 'status' => WP_Http::NOT_FOUND )262			);263		}264 265		$remote_body = wp_remote_retrieve_body( $response );266 267		if ( empty( $remote_body ) ) {268			return new WP_Error(269				'no_content',270				__( 'Unable to retrieve body from response at this URL.' ),271				array( 'status' => WP_Http::NOT_FOUND )272			);273		}274 275		return $remote_body;276	}

Changelog

Introduced in 5.9.0. 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 6.8.8 tag, from src/wp-includes/rest-api/endpoints/class-wp-rest-url-details-controller.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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