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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   * @since 3.6.0
  37   *
  38   * @see wp_remote_request() For more information on the response array format.
  39   * @see WP_Http::request() For default arguments information.
  40   * @see wp_http_validate_url() For more information about how the URL is validated.
  41   *
  42   * @link https://owasp.org/www-community/attacks/Server_Side_Request_Forgery
  43   *
  44   * @param string $url  URL to retrieve.
  45   * @param array  $args Optional. Request arguments. Default empty array.
  46   *                     See WP_Http::request() for information on accepted arguments.
  47   * @return array|WP_Error The response or WP_Error on failure.
  48   */
  49  function wp_safe_remote_request( $url, $args = array() ) {
  50      $args['reject_unsafe_urls'] = true;
  51      $http                       = _wp_http_get_object();
  52      return $http->request( $url, $args );
  53  }
  54  
  55  /**
  56   * Retrieves the raw response from a safe HTTP request using the GET method.
  57   *
  58   * This function is ideal when the HTTP request is being made to an arbitrary
  59   * URL. The URL, and every URL it redirects to, are validated with wp_http_validate_url()
  60   * to avoid Server Side Request Forgery attacks (SSRF).
  61   *
  62   * @since 3.6.0
  63   *
  64   * @see wp_remote_request() For more information on the response array format.
  65   * @see WP_Http::request() For default arguments information.
  66   * @see wp_http_validate_url() For more information about how the URL is validated.
  67   *
  68   * @link https://owasp.org/www-community/attacks/Server_Side_Request_Forgery
  69   *
  70   * @param string $url  URL to retrieve.
  71   * @param array  $args Optional. Request arguments. Default empty array.
  72   *                     See WP_Http::request() for information on accepted arguments.
  73   * @return array|WP_Error The response or WP_Error on failure.
  74   */
  75  function wp_safe_remote_get( $url, $args = array() ) {
  76      $args['reject_unsafe_urls'] = true;
  77      $http                       = _wp_http_get_object();
  78      return $http->get( $url, $args );
  79  }
  80  
  81  /**
  82   * Retrieves the raw response from a safe HTTP request using the POST method.
  83   *
  84   * This function is ideal when the HTTP request is being made to an arbitrary
  85   * URL. The URL, and every URL it redirects to, are validated with wp_http_validate_url()
  86   * to avoid Server Side Request Forgery attacks (SSRF).
  87   *
  88   * @since 3.6.0
  89   *
  90   * @see wp_remote_request() For more information on the response array format.
  91   * @see WP_Http::request() For default arguments information.
  92   * @see wp_http_validate_url() For more information about how the URL is validated.
  93   *
  94   * @link https://owasp.org/www-community/attacks/Server_Side_Request_Forgery
  95   *
  96   * @param string $url  URL to retrieve.
  97   * @param array  $args Optional. Request arguments. Default empty array.
  98   *                     See WP_Http::request() for information on accepted arguments.
  99   * @return array|WP_Error The response or WP_Error on failure.
 100   */
 101  function wp_safe_remote_post( $url, $args = array() ) {
 102      $args['reject_unsafe_urls'] = true;
 103      $http                       = _wp_http_get_object();
 104      return $http->post( $url, $args );
 105  }
 106  
 107  /**
 108   * Retrieves the raw response from a safe HTTP request using the HEAD method.
 109   *
 110   * This function is ideal when the HTTP request is being made to an arbitrary
 111   * URL. The URL, and every URL it redirects to, are validated with wp_http_validate_url()
 112   * to avoid Server Side Request Forgery attacks (SSRF).
 113   *
 114   * @since 3.6.0
 115   *
 116   * @see wp_remote_request() For more information on the response array format.
 117   * @see WP_Http::request() For default arguments information.
 118   * @see wp_http_validate_url() For more information about how the URL is validated.
 119   *
 120   * @link https://owasp.org/www-community/attacks/Server_Side_Request_Forgery
 121   *
 122   * @param string $url  URL to retrieve.
 123   * @param array  $args Optional. Request arguments. Default empty array.
 124   *                     See WP_Http::request() for information on accepted arguments.
 125   * @return array|WP_Error The response or WP_Error on failure.
 126   */
 127  function wp_safe_remote_head( $url, $args = array() ) {
 128      $args['reject_unsafe_urls'] = true;
 129      $http                       = _wp_http_get_object();
 130      return $http->head( $url, $args );
 131  }
 132  
 133  /**
 134   * Performs an HTTP request and returns its response.
 135   *
 136   * There are other API functions available which abstract away the HTTP method:
 137   *
 138   *  - Default 'GET'  for wp_remote_get()
 139   *  - Default 'POST' for wp_remote_post()
 140   *  - Default 'HEAD' for wp_remote_head()
 141   *
 142   * @since 2.7.0
 143   *
 144   * @see WP_Http::request() For information on default arguments.
 145   *
 146   * @param string $url  URL to retrieve.
 147   * @param array  $args Optional. Request arguments. Default empty array.
 148   *                     See WP_Http::request() for information on accepted arguments.
 149   * @return array|WP_Error {
 150   *     The response array or a WP_Error on failure.
 151   *
 152   *     @type string[]                       $headers       Array of response headers keyed by their name.
 153   *     @type string                         $body          Response body.
 154   *     @type array                          $response      {
 155   *         Data about the HTTP response.
 156   *
 157   *         @type int|false    $code    HTTP response code.
 158   *         @type string|false $message HTTP response message.
 159   *     }
 160   *     @type WP_HTTP_Cookie[]               $cookies       Array of response cookies.
 161   *     @type WP_HTTP_Requests_Response|null $http_response Raw HTTP response object.
 162   * }
 163   */
 164  function wp_remote_request( $url, $args = array() ) {
 165      $http = _wp_http_get_object();
 166      return $http->request( $url, $args );
 167  }
 168  
 169  /**
 170   * Performs an HTTP request using the GET method and returns its response.
 171   *
 172   * @since 2.7.0
 173   *
 174   * @see wp_remote_request() For more information on the response array format.
 175   * @see WP_Http::request() For default arguments information.
 176   *
 177   * @param string $url  URL to retrieve.
 178   * @param array  $args Optional. Request arguments. Default empty array.
 179   *                     See WP_Http::request() for information on accepted arguments.
 180   * @return array|WP_Error The response or WP_Error on failure.
 181   */
 182  function wp_remote_get( $url, $args = array() ) {
 183      $http = _wp_http_get_object();
 184      return $http->get( $url, $args );
 185  }
 186  
 187  /**
 188   * Performs an HTTP request using the POST method and returns its response.
 189   *
 190   * @since 2.7.0
 191   *
 192   * @see wp_remote_request() For more information on the response array format.
 193   * @see WP_Http::request() For default arguments information.
 194   *
 195   * @param string $url  URL to retrieve.
 196   * @param array  $args Optional. Request arguments. Default empty array.
 197   *                     See WP_Http::request() for information on accepted arguments.
 198   * @return array|WP_Error The response or WP_Error on failure.
 199   */
 200  function wp_remote_post( $url, $args = array() ) {
 201      $http = _wp_http_get_object();
 202      return $http->post( $url, $args );
 203  }
 204  
 205  /**
 206   * Performs an HTTP request using the HEAD method and returns its response.
 207   *
 208   * @since 2.7.0
 209   *
 210   * @see wp_remote_request() For more information on the response array format.
 211   * @see WP_Http::request() For default arguments information.
 212   *
 213   * @param string $url  URL to retrieve.
 214   * @param array  $args Optional. Request arguments. Default empty array.
 215   *                     See WP_Http::request() for information on accepted arguments.
 216   * @return array|WP_Error The response or WP_Error on failure.
 217   */
 218  function wp_remote_head( $url, $args = array() ) {
 219      $http = _wp_http_get_object();
 220      return $http->head( $url, $args );
 221  }
 222  
 223  /**
 224   * Retrieves only the headers from the raw response.
 225   *
 226   * @since 2.7.0
 227   * @since 4.6.0 Return value changed from an array to an WpOrg\Requests\Utility\CaseInsensitiveDictionary instance.
 228   *
 229   * @see \WpOrg\Requests\Utility\CaseInsensitiveDictionary
 230   *
 231   * @param array|WP_Error $response HTTP response.
 232   * @return \WpOrg\Requests\Utility\CaseInsensitiveDictionary|array The headers of the response, or empty array
 233   *                                                                 if incorrect parameter given.
 234   */
 235  function wp_remote_retrieve_headers( $response ) {
 236      if ( is_wp_error( $response ) || ! isset( $response['headers'] ) ) {
 237          return array();
 238      }
 239  
 240      return $response['headers'];
 241  }
 242  
 243  /**
 244   * Retrieves a single header by name from the raw response.
 245   *
 246   * @since 2.7.0
 247   *
 248   * @param array|WP_Error $response HTTP response.
 249   * @param string         $header   Header name to retrieve value from.
 250   * @return array|string The header(s) value(s). Array if multiple headers with the same name are retrieved.
 251   *                      Empty string if incorrect parameter given, or if the header doesn't exist.
 252   */
 253  function wp_remote_retrieve_header( $response, $header ) {
 254      if ( is_wp_error( $response ) || ! isset( $response['headers'] ) ) {
 255          return '';
 256      }
 257  
 258      if ( isset( $response['headers'][ $header ] ) ) {
 259          return $response['headers'][ $header ];
 260      }
 261  
 262      return '';
 263  }
 264  
 265  /**
 266   * Retrieves only the response code from the raw response.
 267   *
 268   * Will return an empty string if incorrect parameter value is given.
 269   *
 270   * @since 2.7.0
 271   *
 272   * @param array|WP_Error $response HTTP response.
 273   * @return int|string The response code as an integer. Empty string if incorrect parameter given.
 274   */
 275  function wp_remote_retrieve_response_code( $response ) {
 276      if ( is_wp_error( $response ) || ! isset( $response['response'] ) || ! is_array( $response['response'] ) ) {
 277          return '';
 278      }
 279  
 280      return $response['response']['code'];
 281  }
 282  
 283  /**
 284   * Retrieves only the response message from the raw response.
 285   *
 286   * Will return an empty string if incorrect parameter value is given.
 287   *
 288   * @since 2.7.0
 289   *
 290   * @param array|WP_Error $response HTTP response.
 291   * @return string The response message. Empty string if incorrect parameter given.
 292   */
 293  function wp_remote_retrieve_response_message( $response ) {
 294      if ( is_wp_error( $response ) || ! isset( $response['response'] ) || ! is_array( $response['response'] ) ) {
 295          return '';
 296      }
 297  
 298      return $response['response']['message'];
 299  }
 300  
 301  /**
 302   * Retrieves only the body from the raw response.
 303   *
 304   * @since 2.7.0
 305   *
 306   * @param array|WP_Error $response HTTP response.
 307   * @return string The body of the response. Empty string if no body or incorrect parameter given.
 308   */
 309  function wp_remote_retrieve_body( $response ) {
 310      if ( is_wp_error( $response ) || ! isset( $response['body'] ) ) {
 311          return '';
 312      }
 313  
 314      return $response['body'];
 315  }
 316  
 317  /**
 318   * Retrieves only the cookies from the raw response.
 319   *
 320   * @since 4.4.0
 321   *
 322   * @param array|WP_Error $response HTTP response.
 323   * @return WP_Http_Cookie[] An array of `WP_Http_Cookie` objects from the response.
 324   *                          Empty array if there are none, or the response is a WP_Error.
 325   */
 326  function wp_remote_retrieve_cookies( $response ) {
 327      if ( is_wp_error( $response ) || empty( $response['cookies'] ) ) {
 328          return array();
 329      }
 330  
 331      return $response['cookies'];
 332  }
 333  
 334  /**
 335   * Retrieves a single cookie by name from the raw response.
 336   *
 337   * @since 4.4.0
 338   *
 339   * @param array|WP_Error $response HTTP response.
 340   * @param string         $name     The name of the cookie to retrieve.
 341   * @return WP_Http_Cookie|string The `WP_Http_Cookie` object, or empty string
 342   *                               if the cookie is not present in the response.
 343   */
 344  function wp_remote_retrieve_cookie( $response, $name ) {
 345      $cookies = wp_remote_retrieve_cookies( $response );
 346  
 347      if ( empty( $cookies ) ) {
 348          return '';
 349      }
 350  
 351      foreach ( $cookies as $cookie ) {
 352          if ( $cookie->name === $name ) {
 353              return $cookie;
 354          }
 355      }
 356  
 357      return '';
 358  }
 359  
 360  /**
 361   * Retrieves a single cookie's value by name from the raw response.
 362   *
 363   * @since 4.4.0
 364   *
 365   * @param array|WP_Error $response HTTP response.
 366   * @param string         $name     The name of the cookie to retrieve.
 367   * @return string The value of the cookie, or empty string
 368   *                if the cookie is not present in the response.
 369   */
 370  function wp_remote_retrieve_cookie_value( $response, $name ) {
 371      $cookie = wp_remote_retrieve_cookie( $response, $name );
 372  
 373      if ( ! ( $cookie instanceof WP_Http_Cookie ) ) {
 374          return '';
 375      }
 376  
 377      return $cookie->value;
 378  }
 379  
 380  /**
 381   * Determines if there is an HTTP Transport that can process this request.
 382   *
 383   * @since 3.2.0
 384   *
 385   * @param array  $capabilities Array of capabilities to test or a wp_remote_request() $args array.
 386   * @param string $url          Optional. If given, will check if the URL requires SSL and adds
 387   *                             that requirement to the capabilities array.
 388   *
 389   * @return bool
 390   */
 391  function wp_http_supports( $capabilities = array(), $url = null ) {
 392      $capabilities = wp_parse_args( $capabilities );
 393  
 394      $count = count( $capabilities );
 395  
 396      // If we have a numeric $capabilities array, spoof a wp_remote_request() associative $args array.
 397      if ( $count && count( array_filter( array_keys( $capabilities ), 'is_numeric' ) ) === $count ) {
 398          $capabilities = array_combine( array_values( $capabilities ), array_fill( 0, $count, true ) );
 399      }
 400  
 401      if ( $url && ! isset( $capabilities['ssl'] ) ) {
 402          $scheme = parse_url( $url, PHP_URL_SCHEME );
 403          if ( 'https' === $scheme || 'ssl' === $scheme ) {
 404              $capabilities['ssl'] = true;
 405          }
 406      }
 407  
 408      return WpOrg\Requests\Requests::has_capabilities( $capabilities );
 409  }
 410  
 411  /**
 412   * Gets the HTTP Origin of the current request.
 413   *
 414   * @since 3.4.0
 415   *
 416   * @return string URL of the origin. Empty string if no origin.
 417   */
 418  function get_http_origin() {
 419      $origin = '';
 420      if ( ! empty( $_SERVER['HTTP_ORIGIN'] ) ) {
 421          $origin = $_SERVER['HTTP_ORIGIN'];
 422      }
 423  
 424      /**
 425       * Changes the origin of an HTTP request.
 426       *
 427       * @since 3.4.0
 428       *
 429       * @param string $origin The original origin for the request.
 430       */
 431      return apply_filters( 'http_origin', $origin );
 432  }
 433  
 434  /**
 435   * Retrieves list of allowed HTTP origins.
 436   *
 437   * @since 3.4.0
 438   *
 439   * @return string[] Array of origin URLs.
 440   */
 441  function get_allowed_http_origins() {
 442      $admin_origin = parse_url( admin_url() );
 443      $home_origin  = parse_url( home_url() );
 444  
 445      // @todo Preserve port?
 446      $allowed_origins = array_unique(
 447          array(
 448              'http://' . $admin_origin['host'],
 449              'https://' . $admin_origin['host'],
 450              'http://' . $home_origin['host'],
 451              'https://' . $home_origin['host'],
 452          )
 453      );
 454  
 455      /**
 456       * Changes the origin types allowed for HTTP requests.
 457       *
 458       * @since 3.4.0
 459       *
 460       * @param string[] $allowed_origins {
 461       *     Array of default allowed HTTP origins.
 462       *
 463       *     @type string $0 Non-secure URL for admin origin.
 464       *     @type string $1 Secure URL for admin origin.
 465       *     @type string $2 Non-secure URL for home origin.
 466       *     @type string $3 Secure URL for home origin.
 467       * }
 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 for safe use in the HTTP API.
 537   *
 538   * Examples of URLs that are considered unsafe:
 539   *
 540   * - ftp://example.com/caniload.php - Invalid protocol - only http and https are allowed.
 541   * - http:///example.com/caniload.php - Malformed URL.
 542   * - http://user:pass@example.com/caniload.php - Login information.
 543   * - http://exampleeeee.com/caniload.php - Invalid hostname, as the IP cannot be looked up in DNS.
 544   *
 545   * Examples of URLs that are considered unsafe by default:
 546   *
 547   * - http://192.168.0.1/caniload.php - IPs from LAN networks.
 548   *   This can be changed with the {@see 'http_request_host_is_external'} filter.
 549   * - http://198.143.164.252:81/caniload.php - By default, only 80, 443, and 8080 ports are allowed.
 550   *   This can be changed with the {@see 'http_allowed_safe_ports'} filter.
 551   *
 552   * @since 3.5.2
 553   *
 554   * @param string $url Request URL.
 555   * @return string|false URL or false on failure.
 556   */
 557  function wp_http_validate_url( $url ) {
 558      if ( ! is_string( $url ) || '' === $url || is_numeric( $url ) ) {
 559          return false;
 560      }
 561  
 562      $original_url = $url;
 563      $url          = wp_kses_bad_protocol( $url, array( 'http', 'https' ) );
 564      if ( ! $url || strtolower( $url ) !== strtolower( $original_url ) ) {
 565          return false;
 566      }
 567  
 568      $parsed_url = parse_url( $url );
 569      if ( ! $parsed_url || empty( $parsed_url['host'] ) ) {
 570          return false;
 571      }
 572  
 573      if ( isset( $parsed_url['user'] ) || isset( $parsed_url['pass'] ) ) {
 574          return false;
 575      }
 576  
 577      if ( false !== strpbrk( $parsed_url['host'], ':#?[]' ) ) {
 578          return false;
 579      }
 580  
 581      $parsed_home = parse_url( get_option( 'home' ) );
 582      $same_host   = isset( $parsed_home['host'] ) && strtolower( $parsed_home['host'] ) === strtolower( $parsed_url['host'] );
 583      $host        = trim( $parsed_url['host'], '.' );
 584  
 585      if ( ! $same_host ) {
 586          if ( preg_match( '#^(([1-9]?\d|1\d\d|25[0-5]|2[0-4]\d)\.){3}([1-9]?\d|1\d\d|25[0-5]|2[0-4]\d)$#', $host ) ) {
 587              $ip = $host;
 588          } else {
 589              $ip = gethostbyname( $host );
 590              if ( $ip === $host ) { // Error condition for gethostbyname().
 591                  return false;
 592              }
 593          }
 594          if ( $ip ) {
 595              $parts = array_map( 'intval', explode( '.', $ip ) );
 596              if ( 127 === $parts[0] || 10 === $parts[0] || 0 === $parts[0]
 597                  || ( 172 === $parts[0] && 16 <= $parts[1] && 31 >= $parts[1] )
 598                  || ( 192 === $parts[0] && 168 === $parts[1] )
 599              ) {
 600                  // If host appears local, reject unless specifically allowed.
 601                  /**
 602                   * Checks if HTTP request is external or not.
 603                   *
 604                   * Allows to change and allow external requests for the HTTP request.
 605                   *
 606                   * @since 3.6.0
 607                   *
 608                   * @param bool   $external Whether HTTP request is external or not.
 609                   * @param string $host     Host name of the requested URL.
 610                   * @param string $url      Requested URL.
 611                   */
 612                  if ( ! apply_filters( 'http_request_host_is_external', false, $host, $url ) ) {
 613                      return false;
 614                  }
 615              }
 616          }
 617      }
 618  
 619      if ( empty( $parsed_url['port'] ) ) {
 620          return $url;
 621      }
 622  
 623      $port = $parsed_url['port'];
 624  
 625      /**
 626       * Controls the list of ports considered safe in HTTP API.
 627       *
 628       * Allows to change and allow external requests for the HTTP request.
 629       *
 630       * @since 5.9.0
 631       *
 632       * @param int[]  $allowed_ports Array of integers for valid ports.
 633       * @param string $host          Host name of the requested URL.
 634       * @param string $url           Requested URL.
 635       */
 636      $allowed_ports = apply_filters( 'http_allowed_safe_ports', array( 80, 443, 8080 ), $host, $url );
 637      if ( is_array( $allowed_ports ) && in_array( $port, $allowed_ports, true ) ) {
 638          return $url;
 639      }
 640  
 641      if ( $parsed_home && $same_host && isset( $parsed_home['port'] ) && $parsed_home['port'] === $port ) {
 642          return $url;
 643      }
 644  
 645      return false;
 646  }
 647  
 648  /**
 649   * Marks allowed redirect hosts safe for HTTP requests as well.
 650   *
 651   * Attached to the {@see 'http_request_host_is_external'} filter.
 652   *
 653   * @since 3.6.0
 654   *
 655   * @param bool   $is_external
 656   * @param string $host
 657   * @return bool
 658   */
 659  function allowed_http_request_hosts( $is_external, $host ) {
 660      if ( ! $is_external && wp_validate_redirect( 'http://' . $host ) ) {
 661          $is_external = true;
 662      }
 663      return $is_external;
 664  }
 665  
 666  /**
 667   * Adds any domain in a multisite installation for safe HTTP requests to the
 668   * allowed list.
 669   *
 670   * Attached to the {@see 'http_request_host_is_external'} filter.
 671   *
 672   * @since 3.6.0
 673   *
 674   * @global wpdb $wpdb WordPress database abstraction object.
 675   *
 676   * @param bool   $is_external
 677   * @param string $host
 678   * @return bool
 679   */
 680  function ms_allowed_http_request_hosts( $is_external, $host ) {
 681      global $wpdb;
 682      static $queried = array();
 683      if ( $is_external ) {
 684          return $is_external;
 685      }
 686      if ( get_network()->domain === $host ) {
 687          return true;
 688      }
 689      if ( isset( $queried[ $host ] ) ) {
 690          return $queried[ $host ];
 691      }
 692      $queried[ $host ] = (bool) $wpdb->get_var( $wpdb->prepare( "SELECT domain FROM $wpdb->blogs WHERE domain = %s LIMIT 1", $host ) );
 693      return $queried[ $host ];
 694  }
 695  
 696  /**
 697   * A wrapper for PHP's parse_url() function that handles consistency in the return values
 698   * across PHP versions.
 699   *
 700   * Across various PHP versions, schemeless URLs containing a ":" in the query
 701   * are being handled inconsistently. This function works around those differences.
 702   *
 703   * @since 4.4.0
 704   * @since 4.7.0 The `$component` parameter was added for parity with PHP's `parse_url()`.
 705   *
 706   * @link https://www.php.net/manual/en/function.parse-url.php
 707   *
 708   * @param string $url       The URL to parse.
 709   * @param int    $component The specific component to retrieve. Use one of the PHP
 710   *                          predefined constants to specify which one.
 711   *                          Defaults to -1 (= return all parts as an array).
 712   * @return mixed False on parse failure; Array of URL components on success;
 713   *               When a specific component has been requested: null if the component
 714   *               doesn't exist in the given URL; a string or - in the case of
 715   *               PHP_URL_PORT - integer when it does. See parse_url()'s return values.
 716   */
 717  function wp_parse_url( $url, $component = -1 ) {
 718      $to_unset = array();
 719      $url      = (string) $url;
 720  
 721      if ( str_starts_with( $url, '//' ) ) {
 722          $to_unset[] = 'scheme';
 723          $url        = 'placeholder:' . $url;
 724      } elseif ( str_starts_with( $url, '/' ) ) {
 725          $to_unset[] = 'scheme';
 726          $to_unset[] = 'host';
 727          $url        = 'placeholder://placeholder' . $url;
 728      }
 729  
 730      $parts = parse_url( $url );
 731  
 732      if ( false === $parts ) {
 733          // Parsing failure.
 734          return $parts;
 735      }
 736  
 737      // Remove the placeholder values.
 738      foreach ( $to_unset as $key ) {
 739          unset( $parts[ $key ] );
 740      }
 741  
 742      return _get_component_from_parsed_url_array( $parts, $component );
 743  }
 744  
 745  /**
 746   * Retrieves a specific component from a parsed URL array.
 747   *
 748   * @internal
 749   *
 750   * @since 4.7.0
 751   * @access private
 752   *
 753   * @link https://www.php.net/manual/en/function.parse-url.php
 754   *
 755   * @param array|false $url_parts The parsed URL. Can be false if the URL failed to parse.
 756   * @param int         $component The specific component to retrieve. Use one of the PHP
 757   *                               predefined constants to specify which one.
 758   *                               Defaults to -1 (= return all parts as an array).
 759   * @return mixed False on parse failure; Array of URL components on success;
 760   *               When a specific component has been requested: null if the component
 761   *               doesn't exist in the given URL; a string or - in the case of
 762   *               PHP_URL_PORT - integer when it does. See parse_url()'s return values.
 763   */
 764  function _get_component_from_parsed_url_array( $url_parts, $component = -1 ) {
 765      if ( -1 === $component ) {
 766          return $url_parts;
 767      }
 768  
 769      $key = _wp_translate_php_url_constant_to_key( $component );
 770      if ( false !== $key && is_array( $url_parts ) && isset( $url_parts[ $key ] ) ) {
 771          return $url_parts[ $key ];
 772      } else {
 773          return null;
 774      }
 775  }
 776  
 777  /**
 778   * Translates a PHP_URL_* constant to the named array keys PHP uses.
 779   *
 780   * @internal
 781   *
 782   * @since 4.7.0
 783   * @access private
 784   *
 785   * @link https://www.php.net/manual/en/url.constants.php
 786   *
 787   * @param int $constant PHP_URL_* constant.
 788   * @return string|false The named key or false.
 789   */
 790  function _wp_translate_php_url_constant_to_key( $constant ) {
 791      $translation = array(
 792          PHP_URL_SCHEME   => 'scheme',
 793          PHP_URL_HOST     => 'host',
 794          PHP_URL_PORT     => 'port',
 795          PHP_URL_USER     => 'user',
 796          PHP_URL_PASS     => 'pass',
 797          PHP_URL_PATH     => 'path',
 798          PHP_URL_QUERY    => 'query',
 799          PHP_URL_FRAGMENT => 'fragment',
 800      );
 801  
 802      if ( isset( $translation[ $constant ] ) ) {
 803          return $translation[ $constant ];
 804      } else {
 805          return false;
 806      }
 807  }