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   1  <?php
   2  /**
   3   * Core HTTP Request API
   4   *
   5   * Standardizes the HTTP requests for WordPress. Handles cookies, gzip encoding and decoding, chunk
   6   * decoding, if HTTP 1.1 and various other difficult HTTP protocol implementations.
   7   *
   8   * @package WordPress
   9   * @subpackage HTTP
  10   */
  11  
  12  /**
  13   * Returns the initialized WP_Http Object
  14   *
  15   * @since 2.7.0
  16   * @access private
  17   *
  18   * @return WP_Http HTTP Transport object.
  19   */
  20  function _wp_http_get_object() {
  21      static $http = null;
  22  
  23      if ( is_null( $http ) ) {
  24          $http = new WP_Http();
  25      }
  26      return $http;
  27  }
  28  
  29  /**
  30   * Retrieves the raw response from a safe HTTP request.
  31   *
  32   * This function is ideal when the HTTP request is being made to an arbitrary
  33   * URL. The URL, and every URL it redirects to, are validated with wp_http_validate_url()
  34   * to avoid Server Side Request Forgery attacks (SSRF).
  35   *
  36   * The only supported protocols are `http` and `https`.
  37   *
  38   * @since 3.6.0
  39   *
  40   * @see wp_remote_request() For more information on the response array format.
  41   * @see WP_Http::request() For default arguments information.
  42   * @see wp_http_validate_url() For more information about how the URL is validated.
  43   *
  44   * @link https://owasp.org/www-community/attacks/Server_Side_Request_Forgery
  45   *
  46   * @param string $url  URL to retrieve.
  47   * @param array  $args Optional. Request arguments. Default empty array.
  48   *                     See WP_Http::request() for information on accepted arguments.
  49   * @return array|WP_Error The response or WP_Error on failure.
  50   *                        See WP_Http::request() for information on return value.
  51   */
  52  function wp_safe_remote_request( $url, $args = array() ) {
  53      $args['reject_unsafe_urls'] = true;
  54      $http                       = _wp_http_get_object();
  55      return $http->request( $url, $args );
  56  }
  57  
  58  /**
  59   * Retrieves the raw response from a safe HTTP request using the GET method.
  60   *
  61   * This function is ideal when the HTTP request is being made to an arbitrary
  62   * URL. The URL, and every URL it redirects to, are validated with wp_http_validate_url()
  63   * to avoid Server Side Request Forgery attacks (SSRF).
  64   *
  65   * The only supported protocols are `http` and `https`.
  66   *
  67   * @since 3.6.0
  68   *
  69   * @see wp_remote_request() For more information on the response array format.
  70   * @see WP_Http::request() For default arguments information.
  71   * @see wp_http_validate_url() For more information about how the URL is validated.
  72   *
  73   * @link https://owasp.org/www-community/attacks/Server_Side_Request_Forgery
  74   *
  75   * @param string $url  URL to retrieve.
  76   * @param array  $args Optional. Request arguments. Default empty array.
  77   *                     See WP_Http::request() for information on accepted arguments.
  78   * @return array|WP_Error The response or WP_Error on failure.
  79   *                        See WP_Http::request() for information on return value.
  80   */
  81  function wp_safe_remote_get( $url, $args = array() ) {
  82      $args['reject_unsafe_urls'] = true;
  83      $http                       = _wp_http_get_object();
  84      return $http->get( $url, $args );
  85  }
  86  
  87  /**
  88   * Retrieves the raw response from a safe HTTP request using the POST method.
  89   *
  90   * This function is ideal when the HTTP request is being made to an arbitrary
  91   * URL. The URL, and every URL it redirects to, are validated with wp_http_validate_url()
  92   * to avoid Server Side Request Forgery attacks (SSRF).
  93   *
  94   * The only supported protocols are `http` and `https`.
  95   *
  96   * @since 3.6.0
  97   *
  98   * @see wp_remote_request() For more information on the response array format.
  99   * @see WP_Http::request() For default arguments information.
 100   * @see wp_http_validate_url() For more information about how the URL is validated.
 101   *
 102   * @link https://owasp.org/www-community/attacks/Server_Side_Request_Forgery
 103   *
 104   * @param string $url  URL to retrieve.
 105   * @param array  $args Optional. Request arguments. Default empty array.
 106   *                     See WP_Http::request() for information on accepted arguments.
 107   * @return array|WP_Error The response or WP_Error on failure.
 108   *                        See WP_Http::request() for information on return value.
 109   */
 110  function wp_safe_remote_post( $url, $args = array() ) {
 111      $args['reject_unsafe_urls'] = true;
 112      $http                       = _wp_http_get_object();
 113      return $http->post( $url, $args );
 114  }
 115  
 116  /**
 117   * Retrieves the raw response from a safe HTTP request using the HEAD method.
 118   *
 119   * This function is ideal when the HTTP request is being made to an arbitrary
 120   * URL. The URL, and every URL it redirects to, are validated with wp_http_validate_url()
 121   * to avoid Server Side Request Forgery attacks (SSRF).
 122   *
 123   * The only supported protocols are `http` and `https`.
 124   *
 125   * @since 3.6.0
 126   *
 127   * @see wp_remote_request() For more information on the response array format.
 128   * @see WP_Http::request() For default arguments information.
 129   * @see wp_http_validate_url() For more information about how the URL is validated.
 130   *
 131   * @link https://owasp.org/www-community/attacks/Server_Side_Request_Forgery
 132   *
 133   * @param string $url  URL to retrieve.
 134   * @param array  $args Optional. Request arguments. Default empty array.
 135   *                     See WP_Http::request() for information on accepted arguments.
 136   * @return array|WP_Error The response or WP_Error on failure.
 137   *                        See WP_Http::request() for information on return value.
 138   */
 139  function wp_safe_remote_head( $url, $args = array() ) {
 140      $args['reject_unsafe_urls'] = true;
 141      $http                       = _wp_http_get_object();
 142      return $http->head( $url, $args );
 143  }
 144  
 145  /**
 146   * Performs an HTTP request and returns its response.
 147   *
 148   * There are other API functions available which abstract away the HTTP method:
 149   *
 150   *  - Default 'GET'  for wp_remote_get()
 151   *  - Default 'POST' for wp_remote_post()
 152   *  - Default 'HEAD' for wp_remote_head()
 153   *
 154   * Important: If the URL is user-controlled, use `wp_safe_remote_request()` instead.
 155   *
 156   * @since 2.7.0
 157   *
 158   * @see WP_Http::request() For information on default arguments.
 159   *
 160   * @param string $url  URL to retrieve.
 161   * @param array  $args Optional. Request arguments. Default empty array.
 162   *                     See WP_Http::request() for information on accepted arguments.
 163   * @return array|WP_Error The response array or a WP_Error on failure.
 164   *                        See WP_Http::request() for information on return value.
 165   */
 166  function wp_remote_request( $url, $args = array() ) {
 167      $http = _wp_http_get_object();
 168      return $http->request( $url, $args );
 169  }
 170  
 171  /**
 172   * Performs an HTTP request using the GET method and returns its response.
 173   *
 174   * Important: If the URL is user-controlled, use `wp_safe_remote_get()` instead.
 175   *
 176   * @since 2.7.0
 177   *
 178   * @see wp_remote_request() For more information on the response array format.
 179   * @see WP_Http::request() For default arguments information.
 180   *
 181   * @param string $url  URL to retrieve.
 182   * @param array  $args Optional. Request arguments. Default empty array.
 183   *                     See WP_Http::request() for information on accepted arguments.
 184   * @return array|WP_Error The response or WP_Error on failure.
 185   *                        See WP_Http::request() for information on return value.
 186   */
 187  function wp_remote_get( $url, $args = array() ) {
 188      $http = _wp_http_get_object();
 189      return $http->get( $url, $args );
 190  }
 191  
 192  /**
 193   * Performs an HTTP request using the POST method and returns its response.
 194   *
 195   * Important: If the URL is user-controlled, use `wp_safe_remote_post()` instead.
 196   *
 197   * @since 2.7.0
 198   *
 199   * @see wp_remote_request() For more information on the response array format.
 200   * @see WP_Http::request() For default arguments information.
 201   *
 202   * @param string $url  URL to retrieve.
 203   * @param array  $args Optional. Request arguments. Default empty array.
 204   *                     See WP_Http::request() for information on accepted arguments.
 205   * @return array|WP_Error The response or WP_Error on failure.
 206   *                        See WP_Http::request() for information on return value.
 207   */
 208  function wp_remote_post( $url, $args = array() ) {
 209      $http = _wp_http_get_object();
 210      return $http->post( $url, $args );
 211  }
 212  
 213  /**
 214   * Performs an HTTP request using the HEAD method and returns its response.
 215   *
 216   * Important: If the URL is user-controlled, use `wp_safe_remote_head()` instead.
 217   *
 218   * @since 2.7.0
 219   *
 220   * @see wp_remote_request() For more information on the response array format.
 221   * @see WP_Http::request() For default arguments information.
 222   *
 223   * @param string $url  URL to retrieve.
 224   * @param array  $args Optional. Request arguments. Default empty array.
 225   *                     See WP_Http::request() for information on accepted arguments.
 226   * @return array|WP_Error The response or WP_Error on failure.
 227   *                        See WP_Http::request() for information on return value.
 228   */
 229  function wp_remote_head( $url, $args = array() ) {
 230      $http = _wp_http_get_object();
 231      return $http->head( $url, $args );
 232  }
 233  
 234  /**
 235   * Retrieves only the headers from the raw response.
 236   *
 237   * @since 2.7.0
 238   * @since 4.6.0 Return value changed from an array to an WpOrg\Requests\Utility\CaseInsensitiveDictionary instance.
 239   *
 240   * @see \WpOrg\Requests\Utility\CaseInsensitiveDictionary
 241   *
 242   * @param array|WP_Error $response HTTP response.
 243   * @return \WpOrg\Requests\Utility\CaseInsensitiveDictionary|array The headers of the response, or empty array
 244   *                                                                 if incorrect parameter given.
 245   */
 246  function wp_remote_retrieve_headers( $response ) {
 247      if ( is_wp_error( $response ) || ! isset( $response['headers'] ) ) {
 248          return array();
 249      }
 250  
 251      return $response['headers'];
 252  }
 253  
 254  /**
 255   * Retrieves a single header by name from the raw response.
 256   *
 257   * @since 2.7.0
 258   *
 259   * @param array|WP_Error $response HTTP response.
 260   * @param string         $header   Header name to retrieve value from.
 261   * @return array|string The header(s) value(s). Array if multiple headers with the same name are retrieved.
 262   *                      Empty string if incorrect parameter given, or if the header doesn't exist.
 263   */
 264  function wp_remote_retrieve_header( $response, $header ) {
 265      if ( is_wp_error( $response ) || ! isset( $response['headers'] ) ) {
 266          return '';
 267      }
 268  
 269      return $response['headers'][ $header ] ?? '';
 270  }
 271  
 272  /**
 273   * Retrieves only the response code from the raw response.
 274   *
 275   * Will return an empty string if incorrect parameter value is given.
 276   *
 277   * @since 2.7.0
 278   *
 279   * @param array|WP_Error $response HTTP response.
 280   * @return int|string The response code as an integer. Empty string if incorrect parameter given.
 281   */
 282  function wp_remote_retrieve_response_code( $response ) {
 283      if ( is_wp_error( $response ) || ! isset( $response['response'] ) || ! is_array( $response['response'] ) ) {
 284          return '';
 285      }
 286  
 287      return $response['response']['code'];
 288  }
 289  
 290  /**
 291   * Retrieves only the response message from the raw response.
 292   *
 293   * Will return an empty string if incorrect parameter value is given.
 294   *
 295   * @since 2.7.0
 296   *
 297   * @param array|WP_Error $response HTTP response.
 298   * @return string The response message. Empty string if incorrect parameter given.
 299   */
 300  function wp_remote_retrieve_response_message( $response ) {
 301      if ( is_wp_error( $response ) || ! isset( $response['response'] ) || ! is_array( $response['response'] ) ) {
 302          return '';
 303      }
 304  
 305      return $response['response']['message'];
 306  }
 307  
 308  /**
 309   * Retrieves only the body from the raw response.
 310   *
 311   * @since 2.7.0
 312   *
 313   * @param array|WP_Error $response HTTP response.
 314   * @return string The body of the response. Empty string if no body or incorrect parameter given.
 315   */
 316  function wp_remote_retrieve_body( $response ) {
 317      if ( is_wp_error( $response ) || ! isset( $response['body'] ) ) {
 318          return '';
 319      }
 320  
 321      return $response['body'];
 322  }
 323  
 324  /**
 325   * Retrieves only the cookies from the raw response.
 326   *
 327   * @since 4.4.0
 328   *
 329   * @param array|WP_Error $response HTTP response.
 330   * @return WP_Http_Cookie[] An array of `WP_Http_Cookie` objects from the response.
 331   *                          Empty array if there are none, or the response is a WP_Error.
 332   */
 333  function wp_remote_retrieve_cookies( $response ) {
 334      if ( is_wp_error( $response ) || empty( $response['cookies'] ) ) {
 335          return array();
 336      }
 337  
 338      return $response['cookies'];
 339  }
 340  
 341  /**
 342   * Retrieves a single cookie by name from the raw response.
 343   *
 344   * @since 4.4.0
 345   *
 346   * @param array|WP_Error $response HTTP response.
 347   * @param string         $name     The name of the cookie to retrieve.
 348   * @return WP_Http_Cookie|string The `WP_Http_Cookie` object, or empty string
 349   *                               if the cookie is not present in the response.
 350   */
 351  function wp_remote_retrieve_cookie( $response, $name ) {
 352      $cookies = wp_remote_retrieve_cookies( $response );
 353  
 354      if ( empty( $cookies ) ) {
 355          return '';
 356      }
 357  
 358      foreach ( $cookies as $cookie ) {
 359          if ( $cookie->name === $name ) {
 360              return $cookie;
 361          }
 362      }
 363  
 364      return '';
 365  }
 366  
 367  /**
 368   * Retrieves a single cookie's value by name from the raw response.
 369   *
 370   * @since 4.4.0
 371   *
 372   * @param array|WP_Error $response HTTP response.
 373   * @param string         $name     The name of the cookie to retrieve.
 374   * @return string The value of the cookie, or empty string
 375   *                if the cookie is not present in the response.
 376   */
 377  function wp_remote_retrieve_cookie_value( $response, $name ) {
 378      $cookie = wp_remote_retrieve_cookie( $response, $name );
 379  
 380      if ( ! ( $cookie instanceof WP_Http_Cookie ) ) {
 381          return '';
 382      }
 383  
 384      return $cookie->value;
 385  }
 386  
 387  /**
 388   * Determines if there is an HTTP Transport that can process this request.
 389   *
 390   * @since 3.2.0
 391   *
 392   * @param array  $capabilities Array of capabilities to test or a wp_remote_request() $args array.
 393   * @param string $url          Optional. If given, will check if the URL requires SSL and adds
 394   *                             that requirement to the capabilities array.
 395   *
 396   * @return bool
 397   */
 398  function wp_http_supports( $capabilities = array(), $url = null ) {
 399      $capabilities = wp_parse_args( $capabilities );
 400  
 401      $count = count( $capabilities );
 402  
 403      // If we have a numeric $capabilities array, spoof a wp_remote_request() associative $args array.
 404      if ( $count && count( array_filter( array_keys( $capabilities ), 'is_numeric' ) ) === $count ) {
 405          $capabilities = array_combine( array_values( $capabilities ), array_fill( 0, $count, true ) );
 406      }
 407  
 408      if ( $url && ! isset( $capabilities['ssl'] ) ) {
 409          $scheme = parse_url( $url, PHP_URL_SCHEME );
 410          if ( 'https' === $scheme || 'ssl' === $scheme ) {
 411              $capabilities['ssl'] = true;
 412          }
 413      }
 414  
 415      return WpOrg\Requests\Requests::has_capabilities( $capabilities );
 416  }
 417  
 418  /**
 419   * Gets the HTTP Origin of the current request.
 420   *
 421   * @since 3.4.0
 422   *
 423   * @return string URL of the origin. Empty string if no origin.
 424   */
 425  function get_http_origin() {
 426      $origin = '';
 427      if ( ! empty( $_SERVER['HTTP_ORIGIN'] ) ) {
 428          $origin = $_SERVER['HTTP_ORIGIN'];
 429      }
 430  
 431      /**
 432       * Changes the origin of an HTTP request.
 433       *
 434       * @since 3.4.0
 435       *
 436       * @param string $origin The HTTP origin for the request.
 437       */
 438      return apply_filters( 'http_origin', $origin );
 439  }
 440  
 441  /**
 442   * Retrieves list of allowed HTTP origins.
 443   *
 444   * @since 3.4.0
 445   *
 446   * @return string[] Array of origin URLs.
 447   */
 448  function get_allowed_http_origins() {
 449      $admin_origin = parse_url( admin_url() );
 450      $home_origin  = parse_url( home_url() );
 451  
 452      // @todo Preserve port?
 453      $allowed_origins = array_unique(
 454          array(
 455              'http://' . $admin_origin['host'],
 456              'https://' . $admin_origin['host'],
 457              'http://' . $home_origin['host'],
 458              'https://' . $home_origin['host'],
 459          )
 460      );
 461  
 462      /**
 463       * Changes the origin types allowed for HTTP requests.
 464       *
 465       * @since 3.4.0
 466       *
 467       * @param string[] $allowed_origins Array of allowed HTTP origins.
 468       */
 469      return apply_filters( 'allowed_http_origins', $allowed_origins );
 470  }
 471  
 472  /**
 473   * Determines if the HTTP origin is an authorized one.
 474   *
 475   * @since 3.4.0
 476   *
 477   * @param string|null $origin Origin URL. If not provided, the value of get_http_origin() is used.
 478   * @return string Origin URL if allowed, empty string if not.
 479   */
 480  function is_allowed_http_origin( $origin = null ) {
 481      $origin_arg = $origin;
 482  
 483      if ( null === $origin ) {
 484          $origin = get_http_origin();
 485      }
 486  
 487      if ( $origin && ! in_array( $origin, get_allowed_http_origins(), true ) ) {
 488          $origin = '';
 489      }
 490  
 491      /**
 492       * Changes the allowed HTTP origin result.
 493       *
 494       * @since 3.4.0
 495       *
 496       * @param string $origin     Origin URL if allowed, empty string if not.
 497       * @param string $origin_arg Original origin string passed into is_allowed_http_origin function.
 498       */
 499      return apply_filters( 'allowed_http_origin', $origin, $origin_arg );
 500  }
 501  
 502  /**
 503   * Sends Access-Control-Allow-Origin and related headers if the current request
 504   * is from an allowed origin.
 505   *
 506   * If the request is an OPTIONS request, the script exits with either access
 507   * control headers sent, or a 403 response if the origin is not allowed. For
 508   * other request methods, you will receive a return value.
 509   *
 510   * @since 3.4.0
 511   *
 512   * @return string|false Returns the origin URL if headers are sent. Returns false
 513   *                      if headers are not sent.
 514   */
 515  function send_origin_headers() {
 516      $origin = get_http_origin();
 517  
 518      if ( is_allowed_http_origin( $origin ) ) {
 519          header( 'Access-Control-Allow-Origin: ' . $origin );
 520          header( 'Access-Control-Allow-Credentials: true' );
 521          if ( 'OPTIONS' === $_SERVER['REQUEST_METHOD'] ) {
 522              exit;
 523          }
 524          return $origin;
 525      }
 526  
 527      if ( 'OPTIONS' === $_SERVER['REQUEST_METHOD'] ) {
 528          status_header( 403 );
 529          exit;
 530      }
 531  
 532      return false;
 533  }
 534  
 535  /**
 536   * Validates a URL as safe for use in the HTTP API.
 537   *
 538   * The only supported protocols are `http` and `https`.
 539   *
 540   * Examples of URLs that are considered unsafe:
 541   *
 542   * - `ftp://example.com/caniload.php` - Invalid protocol - only http and https are allowed.
 543   * - `http:///example.com/caniload.php` - Malformed URL.
 544   * - `http://user:pass@example.com/caniload.php` - Login information.
 545   * - `http://example.invalid/caniload.php` - Invalid hostname, as the IP cannot be looked up in DNS.
 546   *
 547   * Examples of URLs that are considered unsafe by default but can be allowed with filters:
 548   *
 549   * - `http://192.168.0.1/caniload.php` - IP address from LAN network.
 550   *   This can be changed with the {@see 'http_request_host_is_external'} filter.
 551   * - `http://198.143.164.252:81/caniload.php` - By default, only ports 80, 443, and 8080 are allowed.
 552   *   This can be changed with the {@see 'http_allowed_safe_ports'} filter.
 553   *
 554   * @since 3.5.2
 555   *
 556   * @param string $url Request URL.
 557   * @return string|false Returns false if the URL is not safe, or the original URL if it is safe.
 558   */
 559  function 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              if ( 127 === $parts[0] || 10 === $parts[0] || 0 === $parts[0]
 599                  || ( 172 === $parts[0] && 16 <= $parts[1] && 31 >= $parts[1] )
 600                  || ( 192 === $parts[0] && 168 === $parts[1] )
 601              ) {
 602                  // If host appears local, reject unless specifically allowed.
 603                  /**
 604                   * Checks if HTTP request is external or not.
 605                   *
 606                   * Allows to change and allow external requests for the HTTP request.
 607                   *
 608                   * @since 3.6.0
 609                   *
 610                   * @param bool   $external Whether HTTP request is external or not.
 611                   * @param string $host     Host name of the requested URL.
 612                   * @param string $url      Requested URL.
 613                   */
 614                  if ( ! apply_filters( 'http_request_host_is_external', false, $host, $url ) ) {
 615                      return false;
 616                  }
 617              }
 618          }
 619      }
 620  
 621      if ( empty( $parsed_url['port'] ) ) {
 622          return $url;
 623      }
 624  
 625      $port = $parsed_url['port'];
 626  
 627      /**
 628       * Controls the list of ports considered safe in HTTP API.
 629       *
 630       * Allows to change and allow external requests for the HTTP request.
 631       *
 632       * @since 5.9.0
 633       *
 634       * @param int[]  $allowed_ports Array of integers for valid ports. Default allowed ports
 635       *                              are 80, 443, and 8080.
 636       * @param string $host          Host name of the requested URL.
 637       * @param string $url           Requested URL.
 638       */
 639      $allowed_ports = apply_filters( 'http_allowed_safe_ports', array( 80, 443, 8080 ), $host, $url );
 640      if ( is_array( $allowed_ports ) && in_array( $port, $allowed_ports, true ) ) {
 641          return $url;
 642      }
 643  
 644      if ( $parsed_home && $same_host && isset( $parsed_home['port'] ) && $parsed_home['port'] === $port ) {
 645          return $url;
 646      }
 647  
 648      return false;
 649  }
 650  
 651  /**
 652   * Marks allowed redirect hosts safe for HTTP requests as well.
 653   *
 654   * Attached to the {@see 'http_request_host_is_external'} filter.
 655   *
 656   * @since 3.6.0
 657   *
 658   * @param bool   $is_external
 659   * @param string $host
 660   * @return bool
 661   */
 662  function allowed_http_request_hosts( $is_external, $host ) {
 663      if ( ! $is_external && wp_validate_redirect( 'http://' . $host ) ) {
 664          $is_external = true;
 665      }
 666      return $is_external;
 667  }
 668  
 669  /**
 670   * Adds any domain in a multisite installation for safe HTTP requests to the
 671   * allowed list.
 672   *
 673   * Attached to the {@see 'http_request_host_is_external'} filter.
 674   *
 675   * @since 3.6.0
 676   *
 677   * @global wpdb $wpdb WordPress database abstraction object.
 678   *
 679   * @param bool   $is_external
 680   * @param string $host
 681   * @return bool
 682   */
 683  function ms_allowed_http_request_hosts( $is_external, $host ) {
 684      global $wpdb;
 685      static $queried = array();
 686      if ( $is_external ) {
 687          return $is_external;
 688      }
 689      if ( get_network()->domain === $host ) {
 690          return true;
 691      }
 692      if ( isset( $queried[ $host ] ) ) {
 693          return $queried[ $host ];
 694      }
 695      $queried[ $host ] = (bool) $wpdb->get_var( $wpdb->prepare( "SELECT domain FROM $wpdb->blogs WHERE domain = %s LIMIT 1", $host ) );
 696      return $queried[ $host ];
 697  }
 698  
 699  /**
 700   * A wrapper for PHP's parse_url() function that handles consistency in the return values
 701   * across PHP versions.
 702   *
 703   * Across various PHP versions, schemeless URLs containing a ":" in the query
 704   * are being handled inconsistently. This function works around those differences.
 705   *
 706   * @since 4.4.0
 707   * @since 4.7.0 The `$component` parameter was added for parity with PHP's `parse_url()`.
 708   *
 709   * @link https://www.php.net/manual/en/function.parse-url.php
 710   *
 711   * @param string $url       The URL to parse.
 712   * @param int    $component The specific component to retrieve. Use one of the PHP
 713   *                          predefined constants to specify which one.
 714   *                          Defaults to -1 (= return all parts as an array).
 715   * @return mixed False on parse failure; Array of URL components on success;
 716   *               When a specific component has been requested: null if the component
 717   *               doesn't exist in the given URL; a string or - in the case of
 718   *               PHP_URL_PORT - integer when it does. See parse_url()'s return values.
 719   */
 720  function wp_parse_url( $url, $component = -1 ) {
 721      $to_unset = array();
 722      $url      = (string) $url;
 723  
 724      if ( str_starts_with( $url, '//' ) ) {
 725          $to_unset[] = 'scheme';
 726          $url        = 'placeholder:' . $url;
 727      } elseif ( str_starts_with( $url, '/' ) ) {
 728          $to_unset[] = 'scheme';
 729          $to_unset[] = 'host';
 730          $url        = 'placeholder://placeholder' . $url;
 731      }
 732  
 733      $parts = parse_url( $url );
 734  
 735      if ( false === $parts ) {
 736          // Parsing failure.
 737          return $parts;
 738      }
 739  
 740      // Remove the placeholder values.
 741      foreach ( $to_unset as $key ) {
 742          unset( $parts[ $key ] );
 743      }
 744  
 745      return _get_component_from_parsed_url_array( $parts, $component );
 746  }
 747  
 748  /**
 749   * Retrieves a specific component from a parsed URL array.
 750   *
 751   * @internal
 752   *
 753   * @since 4.7.0
 754   * @access private
 755   *
 756   * @link https://www.php.net/manual/en/function.parse-url.php
 757   *
 758   * @param array|false $url_parts The parsed URL. Can be false if the URL failed to parse.
 759   * @param int         $component The specific component to retrieve. Use one of the PHP
 760   *                               predefined constants to specify which one.
 761   *                               Defaults to -1 (= return all parts as an array).
 762   * @return mixed False on parse failure; Array of URL components on success;
 763   *               When a specific component has been requested: null if the component
 764   *               doesn't exist in the given URL; a string or - in the case of
 765   *               PHP_URL_PORT - integer when it does. See parse_url()'s return values.
 766   */
 767  function _get_component_from_parsed_url_array( $url_parts, $component = -1 ) {
 768      if ( -1 === $component ) {
 769          return $url_parts;
 770      }
 771  
 772      $key = _wp_translate_php_url_constant_to_key( $component );
 773      if ( false !== $key && is_array( $url_parts ) && isset( $url_parts[ $key ] ) ) {
 774          return $url_parts[ $key ];
 775      } else {
 776          return null;
 777      }
 778  }
 779  
 780  /**
 781   * Translates a PHP_URL_* constant to the named array keys PHP uses.
 782   *
 783   * @internal
 784   *
 785   * @since 4.7.0
 786   * @access private
 787   *
 788   * @link https://www.php.net/manual/en/url.constants.php
 789   *
 790   * @param int $constant PHP_URL_* constant.
 791   * @return string|false The named key or false.
 792   */
 793  function _wp_translate_php_url_constant_to_key( $constant ) {
 794      $translation = array(
 795          PHP_URL_SCHEME   => 'scheme',
 796          PHP_URL_HOST     => 'host',
 797          PHP_URL_PORT     => 'port',
 798          PHP_URL_USER     => 'user',
 799          PHP_URL_PASS     => 'pass',
 800          PHP_URL_PATH     => 'path',
 801          PHP_URL_QUERY    => 'query',
 802          PHP_URL_FRAGMENT => 'fragment',
 803      );
 804  
 805      if ( isset( $translation[ $constant ] ) ) {
 806          return $translation[ $constant ];
 807      } else {
 808          return false;
 809      }
 810  }