wp_http_validate_url() │ WP 3.5.2

$url = wp_http_validate_url( $url );

// internal URL
echo wp_http_validate_url('wp-kama.ru'); // false
echo wp_http_validate_url('https://wp-kama.ru'); // https://wp-kama.ru

// external URL
echo wp_http_validate_url('site.com'); // false
echo wp_http_validate_url('http://example.com'); // http://example.com

// URL with user and password
echo wp_http_validate_url('http://username:[email protected]/'); // false

// URL with port
echo wp_http_validate_url('http://example.com:80/'); // http://example.com:80/
echo wp_http_validate_url('http://example.com:123/'); // false

esc_url_raw( $url ) === $url

Changelog

wp_http_validate_url() wp http validate url code ^{WP 7.0.4}

function wp_http_validate_url( $url ) {
	if ( ! is_string( $url ) || '' === $url || is_numeric( $url ) ) {
		return false;
	}

	$original_url = $url;
	$url          = wp_kses_bad_protocol( $url, array( 'http', 'https' ) );
	if ( ! $url || strtolower( $url ) !== strtolower( $original_url ) ) {
		return false;
	}

	$parsed_url = parse_url( $url );
	if ( ! $parsed_url || empty( $parsed_url['host'] ) ) {
		return false;
	}

	if ( isset( $parsed_url['user'] ) || isset( $parsed_url['pass'] ) ) {
		return false;
	}

	if ( false !== strpbrk( $parsed_url['host'], ':#?[]' ) ) {
		return false;
	}

	$parsed_home = parse_url( get_option( 'home' ) );
	$same_host   = isset( $parsed_home['host'] ) && strtolower( $parsed_home['host'] ) === strtolower( $parsed_url['host'] );
	$host        = trim( $parsed_url['host'], '.' );

	if ( ! $same_host ) {
		if ( preg_match( '#^(([1-9]?\d|1\d\d|25[0-5]|2[0-4]\d)\.){3}([1-9]?\d|1\d\d|25[0-5]|2[0-4]\d)$#', $host ) ) {
			$ip = $host;
		} else {
			$ip = gethostbyname( $host );
			if ( $ip === $host ) { // Error condition for gethostbyname().
				return false;
			}
		}
		if ( $ip ) {
			$parts = array_map( 'intval', explode( '.', $ip ) );

			/*
			 * These IP address ranges are not considered valid external hosts for HTTP requests.
			 *
			 * 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.
			 *
			 * References:
			 *
			 * - IPv4 Special-Purpose Address Space: https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml
			 * - IPv4 Multicast Address Assignments: https://www.rfc-editor.org/rfc/rfc5771.html
			 */
			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).
				|| ( 172 === $parts[0] && 16 <= $parts[1] && 31 >= $parts[1] )     // 172.16.0.0/12 (private).
				|| ( 192 === $parts[0] && 168 === $parts[1] )                      // 192.168.0.0/16 (private).
				|| ( 192 === $parts[0] && 0 === $parts[1] && 0 === $parts[2] )     // 192.0.0.0/24 (IETF protocol assignments).
				|| ( 192 === $parts[0] && 0 === $parts[1] && 2 === $parts[2] )     // 192.0.2.0/24 (TEST-NET-1).
				|| ( 192 === $parts[0] && 88 === $parts[1] && 99 === $parts[2] )   // 192.88.99.0/24 (6to4 relay anycast).
				|| ( 198 === $parts[0] && 51 === $parts[1] && 100 === $parts[2] )  // 198.51.100.0/24 (TEST-NET-2).
				|| ( 203 === $parts[0] && 0 === $parts[1] && 113 === $parts[2] )   // 203.0.113.0/24 (TEST-NET-3).
				|| ( 169 === $parts[0] && 254 === $parts[1] )                      // 169.254.0.0/16 (link-local and cloud metadata).
				|| ( 100 === $parts[0] && 64 <= $parts[1] && 127 >= $parts[1] )    // 100.64.0.0/10 (CGNAT).
				|| ( 198 === $parts[0] && 18 <= $parts[1] && 19 >= $parts[1] )     // 198.18.0.0/15 (benchmarking).
				|| ( 224 <= $parts[0] && 239 >= $parts[0] )                        // 224.0.0.0/4 (multicast).
				|| 240 <= $parts[0]                                                // 240.0.0.0/4 (reserved, includes 255.255.255.255 broadcast).
			) {
				// If host appears local, reject unless specifically allowed.
				/**
				 * Checks if HTTP request is external or not.
				 *
				 * Allows to change and allow external requests for the HTTP request.
				 *
				 * @since 3.6.0
				 *
				 * @param bool   $external Whether HTTP request is external or not.
				 * @param string $host     Host name of the requested URL.
				 * @param string $url      Requested URL.
				 */
				if ( ! apply_filters( 'http_request_host_is_external', false, $host, $url ) ) {
					return false;
				}
			}
		}
	}

	if ( empty( $parsed_url['port'] ) ) {
		return $url;
	}

	$port = $parsed_url['port'];

	/**
	 * Controls the list of ports considered safe in HTTP API.
	 *
	 * Allows to change and allow external requests for the HTTP request.
	 *
	 * @since 5.9.0
	 *
	 * @param int[]  $allowed_ports Array of integers for valid ports. Default allowed ports
	 *                              are 80, 443, and 8080.
	 * @param string $host          Host name of the requested URL.
	 * @param string $url           Requested URL.
	 */
	$allowed_ports = apply_filters( 'http_allowed_safe_ports', array( 80, 443, 8080 ), $host, $url );
	if ( is_array( $allowed_ports ) && in_array( $port, $allowed_ports, true ) ) {
		return $url;
	}

	if ( $parsed_home && $same_host && isset( $parsed_home['port'] ) && $parsed_home['port'] === $port ) {
		return $url;
	}

	return false;
}

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