wp_http_validate_url( string $url ): string|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

$urlstring

Request URL.

Return value

string|false

Returns false if the URL is not safe, or the original URL if it is safe.

Performance profile

How much work a call to wp_http_validate_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

4–170

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 224.

Plugin surface

2 hooks

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

Called by

7

7 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 wp_http_validate_url()
• serializeserialisationmaybe_unserialize()one call below wp_http_validate_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 · 10 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_http_validate_url() 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 · 2

2 hooks fire while wp_http_validate_url() runs, in this order:

1. 1
   apply_filters( http_request_host_is_external )filterline 635 (+76 into the body)

   Checks if HTTP request is external or not.

2. 2
   apply_filters( http_allowed_safe_ports )filterline 660 (+101 into the body)

   Controls the list of ports considered safe in HTTP API.

Uses · 3

• wp_kses_bad_protocol()Sanitizes a string and removed disallowed URL protocols.
• get_option()Retrieves an option value based on an option name.
• apply_filters()Calls the callback functions that have been added to a filter hook.

Used by · 7

• WP_Font_Collection::load_from_json()Loads font collection data from a JSON file or URL.
• WP_Http::request()Send an HTTP request to a URI.
• WP_Http::validate_redirects()Validate redirected URLs.
• WP_REST_Font_Faces_Controller::sanitize_src()Sanitizes a single src value for a font face.
• WP_REST_Font_Faces_Controller::validate_create_font_face_settings()Validates settings when creating a font face.
• pingback_ping_source_uri()Default filter attached to pingback_ping_source_uri to validate the pingback's Source URI.
• wp_enqueue_command_palette_assets()Enqueues the assets required for the Command Palette.

Source code

View on Trac ↗View on GitHub ↗

559function wp_http_validate_url( $url ) {560	if ( ! is_string( $url ) || '' === $url || is_numeric( $url ) ) {561		return false;562	}563 564	$original_url = $url;565	$url          = wp_kses_bad_protocol( $url, array( 'http', 'https' ) );566	if ( ! $url || strtolower( $url ) !== strtolower( $original_url ) ) {567		return false;568	}569 570	$parsed_url = parse_url( $url );571	if ( ! $parsed_url || empty( $parsed_url['host'] ) ) {572		return false;573	}574 575	if ( isset( $parsed_url['user'] ) || isset( $parsed_url['pass'] ) ) {576		return false;577	}578 579	if ( false !== strpbrk( $parsed_url['host'], ':#?[]' ) ) {580		return false;581	}582 583	$parsed_home = parse_url( get_option( 'home' ) );584	$same_host   = isset( $parsed_home['host'] ) && strtolower( $parsed_home['host'] ) === strtolower( $parsed_url['host'] );585	$host        = trim( $parsed_url['host'], '.' );586 587	if ( ! $same_host ) {588		if ( preg_match( '#^(([1-9]?\d|1\d\d|25[0-5]|2[0-4]\d)\.){3}([1-9]?\d|1\d\d|25[0-5]|2[0-4]\d)$#', $host ) ) {589			$ip = $host;590		} else {591			$ip = gethostbyname( $host );592			if ( $ip === $host ) { // Error condition for gethostbyname().593				return false;594			}595		}596		if ( $ip ) {597			$parts = array_map( 'intval', explode( '.', $ip ) );598 599			/*600			 * These IP address ranges are not considered valid external hosts for HTTP requests.601			 *602			 * If the host resolves to an IP address in these ranges, the request will be rejected unless the 'http_request_host_is_external' filter allows it.603			 *604			 * References:605			 *606			 * - IPv4 Special-Purpose Address Space: https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml607			 * - IPv4 Multicast Address Assignments: https://www.rfc-editor.org/rfc/rfc5771.html608			 */609			if ( 127 === $parts[0] || 10 === $parts[0] || 0 === $parts[0]          // 127.0.0.0/8 (loopback), 10.0.0.0/8 (private), 0.0.0.0/8 (this network).610				|| ( 172 === $parts[0] && 16 <= $parts[1] && 31 >= $parts[1] )     // 172.16.0.0/12 (private).611				|| ( 192 === $parts[0] && 168 === $parts[1] )                      // 192.168.0.0/16 (private).612				|| ( 192 === $parts[0] && 0 === $parts[1] && 0 === $parts[2] )     // 192.0.0.0/24 (IETF protocol assignments).613				|| ( 192 === $parts[0] && 0 === $parts[1] && 2 === $parts[2] )     // 192.0.2.0/24 (TEST-NET-1).614				|| ( 192 === $parts[0] && 88 === $parts[1] && 99 === $parts[2] )   // 192.88.99.0/24 (6to4 relay anycast).615				|| ( 198 === $parts[0] && 51 === $parts[1] && 100 === $parts[2] )  // 198.51.100.0/24 (TEST-NET-2).616				|| ( 203 === $parts[0] && 0 === $parts[1] && 113 === $parts[2] )   // 203.0.113.0/24 (TEST-NET-3).617				|| ( 169 === $parts[0] && 254 === $parts[1] )                      // 169.254.0.0/16 (link-local and cloud metadata).618				|| ( 100 === $parts[0] && 64 <= $parts[1] && 127 >= $parts[1] )    // 100.64.0.0/10 (CGNAT).619				|| ( 198 === $parts[0] && 18 <= $parts[1] && 19 >= $parts[1] )     // 198.18.0.0/15 (benchmarking).620				|| ( 224 <= $parts[0] && 239 >= $parts[0] )                        // 224.0.0.0/4 (multicast).621				|| 240 <= $parts[0]                                                // 240.0.0.0/4 (reserved, includes 255.255.255.255 broadcast).622			) {623				// If host appears local, reject unless specifically allowed.624				/**625				 * Checks if HTTP request is external or not.626				 *627				 * Allows to change and allow external requests for the HTTP request.628				 *629				 * @since 3.6.0630				 *631				 * @param bool   $external Whether HTTP request is external or not.632				 * @param string $host     Host name of the requested URL.633				 * @param string $url      Requested URL.634				 */635				if ( ! apply_filters( 'http_request_host_is_external', false, $host, $url ) ) {636					return false;637				}638			}

Changelog

Introduced in 3.5.2. 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/http.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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