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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      if ( isset( $response['headers'][ $header ] ) ) {
 270          return $response['headers'][ $header ];
 271      }
 272  
 273      return '';
 274  }
 275  
 276  /**
 277   * Retrieves only the response code from the raw response.
 278   *
 279   * Will return an empty string if incorrect parameter value is given.
 280   *
 281   * @since 2.7.0
 282   *
 283   * @param array|WP_Error $response HTTP response.
 284   * @return int|string The response code as an integer. Empty string if incorrect parameter given.
 285   */
 286  function wp_remote_retrieve_response_code( $response ) {
 287      if ( is_wp_error( $response ) || ! isset( $response['response'] ) || ! is_array( $response['response'] ) ) {
 288          return '';
 289      }
 290  
 291      return $response['response']['code'];
 292  }
 293  
 294  /**
 295   * Retrieves only the response message from the raw response.
 296   *
 297   * Will return an empty string if incorrect parameter value is given.
 298   *
 299   * @since 2.7.0
 300   *
 301   * @param array|WP_Error $response HTTP response.
 302   * @return string The response message. Empty string if incorrect parameter given.
 303   */
 304  function wp_remote_retrieve_response_message( $response ) {
 305      if ( is_wp_error( $response ) || ! isset( $response['response'] ) || ! is_array( $response['response'] ) ) {
 306          return '';
 307      }
 308  
 309      return $response['response']['message'];
 310  }
 311  
 312  /**
 313   * Retrieves only the body from the raw response.
 314   *
 315   * @since 2.7.0
 316   *
 317   * @param array|WP_Error $response HTTP response.
 318   * @return string The body of the response. Empty string if no body or incorrect parameter given.
 319   */
 320  function wp_remote_retrieve_body( $response ) {
 321      if ( is_wp_error( $response ) || ! isset( $response['body'] ) ) {
 322          return '';
 323      }
 324  
 325      return $response['body'];
 326  }
 327  
 328  /**
 329   * Retrieves only the cookies from the raw response.
 330   *
 331   * @since 4.4.0
 332   *
 333   * @param array|WP_Error $response HTTP response.
 334   * @return WP_Http_Cookie[] An array of `WP_Http_Cookie` objects from the response.
 335   *                          Empty array if there are none, or the response is a WP_Error.
 336   */
 337  function wp_remote_retrieve_cookies( $response ) {
 338      if ( is_wp_error( $response ) || empty( $response['cookies'] ) ) {
 339          return array();
 340      }
 341  
 342      return $response['cookies'];
 343  }
 344  
 345  /**
 346   * Retrieves a single cookie by name from the raw response.
 347   *
 348   * @since 4.4.0
 349   *
 350   * @param array|WP_Error $response HTTP response.
 351   * @param string         $name     The name of the cookie to retrieve.
 352   * @return WP_Http_Cookie|string The `WP_Http_Cookie` object, or empty string
 353   *                               if the cookie is not present in the response.
 354   */
 355  function wp_remote_retrieve_cookie( $response, $name ) {
 356      $cookies = wp_remote_retrieve_cookies( $response );
 357  
 358      if ( empty( $cookies ) ) {
 359          return '';
 360      }
 361  
 362      foreach ( $cookies as $cookie ) {
 363          if ( $cookie->name === $name ) {
 364              return $cookie;
 365          }
 366      }
 367  
 368      return '';
 369  }
 370  
 371  /**
 372   * Retrieves a single cookie's value by name from the raw response.
 373   *
 374   * @since 4.4.0
 375   *
 376   * @param array|WP_Error $response HTTP response.
 377   * @param string         $name     The name of the cookie to retrieve.
 378   * @return string The value of the cookie, or empty string
 379   *                if the cookie is not present in the response.
 380   */
 381  function wp_remote_retrieve_cookie_value( $response, $name ) {
 382      $cookie = wp_remote_retrieve_cookie( $response, $name );
 383  
 384      if ( ! ( $cookie instanceof WP_Http_Cookie ) ) {
 385          return '';
 386      }
 387  
 388      return $cookie->value;
 389  }
 390  
 391  /**
 392   * Determines if there is an HTTP Transport that can process this request.
 393   *
 394   * @since 3.2.0
 395   *
 396   * @param array  $capabilities Array of capabilities to test or a wp_remote_request() $args array.
 397   * @param string $url          Optional. If given, will check if the URL requires SSL and adds
 398   *                             that requirement to the capabilities array.
 399   *
 400   * @return bool
 401   */
 402  function wp_http_supports( $capabilities = array(), $url = null ) {
 403      $capabilities = wp_parse_args( $capabilities );
 404  
 405      $count = count( $capabilities );
 406  
 407      // If we have a numeric $capabilities array, spoof a wp_remote_request() associative $args array.
 408      if ( $count && count( array_filter( array_keys( $capabilities ), 'is_numeric' ) ) === $count ) {
 409          $capabilities = array_combine( array_values( $capabilities ), array_fill( 0, $count, true ) );
 410      }
 411  
 412      if ( $url && ! isset( $capabilities['ssl'] ) ) {
 413          $scheme = parse_url( $url, PHP_URL_SCHEME );
 414          if ( 'https' === $scheme || 'ssl' === $scheme ) {
 415              $capabilities['ssl'] = true;
 416          }
 417      }
 418  
 419      return WpOrg\Requests\Requests::has_capabilities( $capabilities );
 420  }
 421  
 422  /**
 423   * Gets the HTTP Origin of the current request.
 424   *
 425   * @since 3.4.0
 426   *
 427   * @return string URL of the origin. Empty string if no origin.
 428   */
 429  function get_http_origin() {
 430      $origin = '';
 431      if ( ! empty( $_SERVER['HTTP_ORIGIN'] ) ) {
 432          $origin = $_SERVER['HTTP_ORIGIN'];
 433      }
 434  
 435      /**
 436       * Changes the origin of an HTTP request.
 437       *
 438       * @since 3.4.0
 439       *
 440       * @param string $origin The HTTP origin for the request.
 441       */
 442      return apply_filters( 'http_origin', $origin );
 443  }
 444  
 445  /**
 446   * Retrieves list of allowed HTTP origins.
 447   *
 448   * @since 3.4.0
 449   *
 450   * @return string[] Array of origin URLs.
 451   */
 452  function get_allowed_http_origins() {
 453      $admin_origin = parse_url( admin_url() );
 454      $home_origin  = parse_url( home_url() );
 455  
 456      // @todo Preserve port?
 457      $allowed_origins = array_unique(
 458          array(
 459              'http://' . $admin_origin['host'],
 460              'https://' . $admin_origin['host'],
 461              'http://' . $home_origin['host'],
 462              'https://' . $home_origin['host'],
 463          )
 464      );
 465  
 466      /**
 467       * Changes the origin types allowed for HTTP requests.
 468       *
 469       * @since 3.4.0
 470       *
 471       * @param string[] $allowed_origins Array of allowed HTTP origins.
 472       */
 473      return apply_filters( 'allowed_http_origins', $allowed_origins );
 474  }
 475  
 476  /**
 477   * Determines if the HTTP origin is an authorized one.
 478   *
 479   * @since 3.4.0
 480   *
 481   * @param string|null $origin Origin URL. If not provided, the value of get_http_origin() is used.
 482   * @return string Origin URL if allowed, empty string if not.
 483   */
 484  function is_allowed_http_origin( $origin = null ) {
 485      $origin_arg = $origin;
 486  
 487      if ( null === $origin ) {
 488          $origin = get_http_origin();
 489      }
 490  
 491      if ( $origin && ! in_array( $origin, get_allowed_http_origins(), true ) ) {
 492          $origin = '';
 493      }
 494  
 495      /**
 496       * Changes the allowed HTTP origin result.
 497       *
 498       * @since 3.4.0
 499       *
 500       * @param string $origin     Origin URL if allowed, empty string if not.
 501       * @param string $origin_arg Original origin string passed into is_allowed_http_origin function.
 502       */
 503      return apply_filters( 'allowed_http_origin', $origin, $origin_arg );
 504  }
 505  
 506  /**
 507   * Sends Access-Control-Allow-Origin and related headers if the current request
 508   * is from an allowed origin.
 509   *
 510   * If the request is an OPTIONS request, the script exits with either access
 511   * control headers sent, or a 403 response if the origin is not allowed. For
 512   * other request methods, you will receive a return value.
 513   *
 514   * @since 3.4.0
 515   *
 516   * @return string|false Returns the origin URL if headers are sent. Returns false
 517   *                      if headers are not sent.
 518   */
 519  function send_origin_headers() {
 520      $origin = get_http_origin();
 521  
 522      if ( is_allowed_http_origin( $origin ) ) {
 523          header( 'Access-Control-Allow-Origin: ' . $origin );
 524          header( 'Access-Control-Allow-Credentials: true' );
 525          if ( 'OPTIONS' === $_SERVER['REQUEST_METHOD'] ) {
 526              exit;
 527          }
 528          return $origin;
 529      }
 530  
 531      if ( 'OPTIONS' === $_SERVER['REQUEST_METHOD'] ) {
 532          status_header( 403 );
 533          exit;
 534      }
 535  
 536      return false;
 537  }
 538  
 539  /**
 540   * Validates a URL as safe for use in the HTTP API.
 541   *
 542   * The only supported protocols are `http` and `https`.
 543   *
 544   * Examples of URLs that are considered unsafe:
 545   *
 546   * - `ftp://example.com/caniload.php` - Invalid protocol - only http and https are allowed.
 547   * - `http:///example.com/caniload.php` - Malformed URL.
 548   * - `http://user:pass@example.com/caniload.php` - Login information.
 549   * - `http://example.invalid/caniload.php` - Invalid hostname, as the IP cannot be looked up in DNS.
 550   *
 551   * Examples of URLs that are considered unsafe by default but can be allowed with filters:
 552   *
 553   * - `http://192.168.0.1/caniload.php` - IP address from LAN network.
 554   *   This can be changed with the {@see 'http_request_host_is_external'} filter.
 555   * - `http://198.143.164.252:81/caniload.php` - By default, only ports 80, 443, and 8080 are allowed.
 556   *   This can be changed with the {@see 'http_allowed_safe_ports'} filter.
 557   *
 558   * @since 3.5.2
 559   *
 560   * @param string $url Request URL.
 561   * @return string|false Returns false if the URL is not safe, or the original URL if it is safe.
 562   */
 563  function wp_http_validate_url( $url ) {
 564      if ( ! is_string( $url ) || '' === $url || is_numeric( $url ) ) {
 565          return false;
 566      }
 567  
 568      $original_url = $url;
 569      $url          = wp_kses_bad_protocol( $url, array( 'http', 'https' ) );
 570      if ( ! $url || strtolower( $url ) !== strtolower( $original_url ) ) {
 571          return false;
 572      }
 573  
 574      $parsed_url = parse_url( $url );
 575      if ( ! $parsed_url || empty( $parsed_url['host'] ) ) {
 576          return false;
 577      }
 578  
 579      if ( isset( $parsed_url['user'] ) || isset( $parsed_url['pass'] ) ) {
 580          return false;
 581      }
 582  
 583      if ( false !== strpbrk( $parsed_url['host'], ':#?[]' ) ) {
 584          return false;
 585      }
 586  
 587      $parsed_home = parse_url( get_option( 'home' ) );
 588      $same_host   = isset( $parsed_home['host'] ) && strtolower( $parsed_home['host'] ) === strtolower( $parsed_url['host'] );
 589      $host        = trim( $parsed_url['host'], '.' );
 590  
 591      if ( ! $same_host ) {
 592          if ( preg_match( '#^(([1-9]?\d|1\d\d|25[0-5]|2[0-4]\d)\.){3}([1-9]?\d|1\d\d|25[0-5]|2[0-4]\d)$#', $host ) ) {
 593              $ip = $host;
 594          } else {
 595              $ip = gethostbyname( $host );
 596              if ( $ip === $host ) { // Error condition for gethostbyname().
 597                  return false;
 598              }
 599          }
 600          if ( $ip ) {
 601              $parts = array_map( 'intval', explode( '.', $ip ) );
 602              if ( 127 === $parts[0] || 10 === $parts[0] || 0 === $parts[0]
 603                  || ( 172 === $parts[0] && 16 <= $parts[1] && 31 >= $parts[1] )
 604                  || ( 192 === $parts[0] && 168 === $parts[1] )
 605              ) {
 606                  // If host appears local, reject unless specifically allowed.
 607                  /**
 608                   * Checks if HTTP request is external or not.
 609                   *
 610                   * Allows to change and allow external requests for the HTTP request.
 611                   *
 612                   * @since 3.6.0
 613                   *
 614                   * @param bool   $external Whether HTTP request is external or not.
 615                   * @param string $host     Host name of the requested URL.
 616                   * @param string $url      Requested URL.
 617                   */
 618                  if ( ! apply_filters( 'http_request_host_is_external', false, $host, $url ) ) {
 619                      return false;
 620                  }
 621              }
 622          }
 623      }
 624  
 625      if ( empty( $parsed_url['port'] ) ) {
 626          return $url;
 627      }
 628  
 629      $port = $parsed_url['port'];
 630  
 631      /**
 632       * Controls the list of ports considered safe in HTTP API.
 633       *
 634       * Allows to change and allow external requests for the HTTP request.
 635       *
 636       * @since 5.9.0
 637       *
 638       * @param int[]  $allowed_ports Array of integers for valid ports. Default allowed ports
 639       *                              are 80, 443, and 8080.
 640       * @param string $host          Host name of the requested URL.
 641       * @param string $url           Requested URL.
 642       */
 643      $allowed_ports = apply_filters( 'http_allowed_safe_ports', array( 80, 443, 8080 ), $host, $url );
 644      if ( is_array( $allowed_ports ) && in_array( $port, $allowed_ports, true ) ) {
 645          return $url;
 646      }
 647  
 648      if ( $parsed_home && $same_host && isset( $parsed_home['port'] ) && $parsed_home['port'] === $port ) {
 649          return $url;
 650      }
 651  
 652      return false;
 653  }
 654  
 655  /**
 656   * Marks allowed redirect hosts safe for HTTP requests as well.
 657   *
 658   * Attached to the {@see 'http_request_host_is_external'} filter.
 659   *
 660   * @since 3.6.0
 661   *
 662   * @param bool   $is_external
 663   * @param string $host
 664   * @return bool
 665   */
 666  function allowed_http_request_hosts( $is_external, $host ) {
 667      if ( ! $is_external && wp_validate_redirect( 'http://' . $host ) ) {
 668          $is_external = true;
 669      }
 670      return $is_external;
 671  }
 672  
 673  /**
 674   * Adds any domain in a multisite installation for safe HTTP requests to the
 675   * allowed list.
 676   *
 677   * Attached to the {@see 'http_request_host_is_external'} filter.
 678   *
 679   * @since 3.6.0
 680   *
 681   * @global wpdb $wpdb WordPress database abstraction object.
 682   *
 683   * @param bool   $is_external
 684   * @param string $host
 685   * @return bool
 686   */
 687  function ms_allowed_http_request_hosts( $is_external, $host ) {
 688      global $wpdb;
 689      static $queried = array();
 690      if ( $is_external ) {
 691          return $is_external;
 692      }
 693      if ( get_network()->domain === $host ) {
 694          return true;
 695      }
 696      if ( isset( $queried[ $host ] ) ) {
 697          return $queried[ $host ];
 698      }
 699      $queried[ $host ] = (bool) $wpdb->get_var( $wpdb->prepare( "SELECT domain FROM $wpdb->blogs WHERE domain = %s LIMIT 1", $host ) );
 700      return $queried[ $host ];
 701  }
 702  
 703  /**
 704   * A wrapper for PHP's parse_url() function that handles consistency in the return values
 705   * across PHP versions.
 706   *
 707   * Across various PHP versions, schemeless URLs containing a ":" in the query
 708   * are being handled inconsistently. This function works around those differences.
 709   *
 710   * @since 4.4.0
 711   * @since 4.7.0 The `$component` parameter was added for parity with PHP's `parse_url()`.
 712   *
 713   * @link https://www.php.net/manual/en/function.parse-url.php
 714   *
 715   * @param string $url       The URL to parse.
 716   * @param int    $component The specific component to retrieve. Use one of the PHP
 717   *                          predefined constants to specify which one.
 718   *                          Defaults to -1 (= return all parts as an array).
 719   * @return mixed False on parse failure; Array of URL components on success;
 720   *               When a specific component has been requested: null if the component
 721   *               doesn't exist in the given URL; a string or - in the case of
 722   *               PHP_URL_PORT - integer when it does. See parse_url()'s return values.
 723   */
 724  function wp_parse_url( $url, $component = -1 ) {
 725      $to_unset = array();
 726      $url      = (string) $url;
 727  
 728      if ( str_starts_with( $url, '//' ) ) {
 729          $to_unset[] = 'scheme';
 730          $url        = 'placeholder:' . $url;
 731      } elseif ( str_starts_with( $url, '/' ) ) {
 732          $to_unset[] = 'scheme';
 733          $to_unset[] = 'host';
 734          $url        = 'placeholder://placeholder' . $url;
 735      }
 736  
 737      $parts = parse_url( $url );
 738  
 739      if ( false === $parts ) {
 740          // Parsing failure.
 741          return $parts;
 742      }
 743  
 744      // Remove the placeholder values.
 745      foreach ( $to_unset as $key ) {
 746          unset( $parts[ $key ] );
 747      }
 748  
 749      return _get_component_from_parsed_url_array( $parts, $component );
 750  }
 751  
 752  /**
 753   * Retrieves a specific component from a parsed URL array.
 754   *
 755   * @internal
 756   *
 757   * @since 4.7.0
 758   * @access private
 759   *
 760   * @link https://www.php.net/manual/en/function.parse-url.php
 761   *
 762   * @param array|false $url_parts The parsed URL. Can be false if the URL failed to parse.
 763   * @param int         $component The specific component to retrieve. Use one of the PHP
 764   *                               predefined constants to specify which one.
 765   *                               Defaults to -1 (= return all parts as an array).
 766   * @return mixed False on parse failure; Array of URL components on success;
 767   *               When a specific component has been requested: null if the component
 768   *               doesn't exist in the given URL; a string or - in the case of
 769   *               PHP_URL_PORT - integer when it does. See parse_url()'s return values.
 770   */
 771  function _get_component_from_parsed_url_array( $url_parts, $component = -1 ) {
 772      if ( -1 === $component ) {
 773          return $url_parts;
 774      }
 775  
 776      $key = _wp_translate_php_url_constant_to_key( $component );
 777      if ( false !== $key && is_array( $url_parts ) && isset( $url_parts[ $key ] ) ) {
 778          return $url_parts[ $key ];
 779      } else {
 780          return null;
 781      }
 782  }
 783  
 784  /**
 785   * Translates a PHP_URL_* constant to the named array keys PHP uses.
 786   *
 787   * @internal
 788   *
 789   * @since 4.7.0
 790   * @access private
 791   *
 792   * @link https://www.php.net/manual/en/url.constants.php
 793   *
 794   * @param int $constant PHP_URL_* constant.
 795   * @return string|false The named key or false.
 796   */
 797  function _wp_translate_php_url_constant_to_key( $constant ) {
 798      $translation = array(
 799          PHP_URL_SCHEME   => 'scheme',
 800          PHP_URL_HOST     => 'host',
 801          PHP_URL_PORT     => 'port',
 802          PHP_URL_USER     => 'user',
 803          PHP_URL_PASS     => 'pass',
 804          PHP_URL_PATH     => 'path',
 805          PHP_URL_QUERY    => 'query',
 806          PHP_URL_FRAGMENT => 'fragment',
 807      );
 808  
 809      if ( isset( $translation[ $constant ] ) ) {
 810          return $translation[ $constant ];
 811      } else {
 812          return false;
 813      }
 814  }