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   1  <?php
   2  /**
   3   * HTTPS detection functions.
   4   *
   5   * @package WordPress
   6   * @since 5.7.0
   7   */
   8  
   9  /**
  10   * Checks whether the website is using HTTPS.
  11   *
  12   * This is based on whether both the home and site URL are using HTTPS.
  13   *
  14   * @since 5.7.0
  15   * @see wp_is_home_url_using_https()
  16   * @see wp_is_site_url_using_https()
  17   *
  18   * @return bool True if using HTTPS, false otherwise.
  19   */
  20  function wp_is_using_https() {
  21      if ( ! wp_is_home_url_using_https() ) {
  22          return false;
  23      }
  24  
  25      return wp_is_site_url_using_https();
  26  }
  27  
  28  /**
  29   * Checks whether the current site URL is using HTTPS.
  30   *
  31   * @since 5.7.0
  32   * @see home_url()
  33   *
  34   * @return bool True if using HTTPS, false otherwise.
  35   */
  36  function wp_is_home_url_using_https() {
  37      return 'https' === wp_parse_url( home_url(), PHP_URL_SCHEME );
  38  }
  39  
  40  /**
  41   * Checks whether the current site's URL where WordPress is stored is using HTTPS.
  42   *
  43   * This checks the URL where WordPress application files (e.g. wp-blog-header.php or the wp-admin/ folder)
  44   * are accessible.
  45   *
  46   * @since 5.7.0
  47   * @see site_url()
  48   *
  49   * @return bool True if using HTTPS, false otherwise.
  50   */
  51  function wp_is_site_url_using_https() {
  52      /*
  53       * Use direct option access for 'siteurl' and manually run the 'site_url'
  54       * filter because `site_url()` will adjust the scheme based on what the
  55       * current request is using.
  56       */
  57      /** This filter is documented in wp-includes/link-template.php */
  58      $site_url = apply_filters( 'site_url', get_option( 'siteurl' ), '', null, null );
  59  
  60      return 'https' === wp_parse_url( $site_url, PHP_URL_SCHEME );
  61  }
  62  
  63  /**
  64   * Checks whether HTTPS is supported for the server and domain.
  65   *
  66   * @since 5.7.0
  67   *
  68   * @return bool True if HTTPS is supported, false otherwise.
  69   */
  70  function wp_is_https_supported() {
  71      $https_detection_errors = get_option( 'https_detection_errors' );
  72  
  73      // If option has never been set by the Cron hook before, run it on-the-fly as fallback.
  74      if ( false === $https_detection_errors ) {
  75          wp_update_https_detection_errors();
  76  
  77          $https_detection_errors = get_option( 'https_detection_errors' );
  78      }
  79  
  80      // If there are no detection errors, HTTPS is supported.
  81      return empty( $https_detection_errors );
  82  }
  83  
  84  /**
  85   * Runs a remote HTTPS request to detect whether HTTPS supported, and stores potential errors.
  86   *
  87   * This internal function is called by a regular Cron hook to ensure HTTPS support is detected and maintained.
  88   *
  89   * @since 6.4.0
  90   * @access private
  91   */
  92  function wp_get_https_detection_errors() {
  93      /**
  94       * Short-circuits the process of detecting errors related to HTTPS support.
  95       *
  96       * Returning a `WP_Error` from the filter will effectively short-circuit the default logic of trying a remote
  97       * request to the site over HTTPS, storing the errors array from the returned `WP_Error` instead.
  98       *
  99       * @since 6.4.0
 100       *
 101       * @param null|WP_Error $pre Error object to short-circuit detection,
 102       *                           or null to continue with the default behavior.
 103       * @return null|WP_Error Error object if HTTPS detection errors are found, null otherwise.
 104       */
 105      $support_errors = apply_filters( 'pre_wp_get_https_detection_errors', null );
 106      if ( is_wp_error( $support_errors ) ) {
 107          return $support_errors->errors;
 108      }
 109  
 110      $support_errors = new WP_Error();
 111  
 112      $response = wp_remote_request(
 113          home_url( '/', 'https' ),
 114          array(
 115              'headers'   => array(
 116                  'Cache-Control' => 'no-cache',
 117              ),
 118              'sslverify' => true,
 119          )
 120      );
 121  
 122      if ( is_wp_error( $response ) ) {
 123          $unverified_response = wp_remote_request(
 124              home_url( '/', 'https' ),
 125              array(
 126                  'headers'   => array(
 127                      'Cache-Control' => 'no-cache',
 128                  ),
 129                  'sslverify' => false,
 130              )
 131          );
 132  
 133          if ( is_wp_error( $unverified_response ) ) {
 134              $support_errors->add(
 135                  'https_request_failed',
 136                  __( 'HTTPS request failed.' )
 137              );
 138          } else {
 139              $support_errors->add(
 140                  'ssl_verification_failed',
 141                  __( 'SSL verification failed.' )
 142              );
 143          }
 144  
 145          $response = $unverified_response;
 146      }
 147  
 148      if ( ! is_wp_error( $response ) ) {
 149          if ( 200 !== wp_remote_retrieve_response_code( $response ) ) {
 150              $support_errors->add( 'bad_response_code', wp_remote_retrieve_response_message( $response ) );
 151          } elseif ( false === wp_is_local_html_output( wp_remote_retrieve_body( $response ) ) ) {
 152              $support_errors->add( 'bad_response_source', __( 'It looks like the response did not come from this site.' ) );
 153          }
 154      }
 155  
 156      return $support_errors->errors;
 157  }
 158  
 159  /**
 160   * Checks whether a given HTML string is likely an output from this WordPress site.
 161   *
 162   * This function attempts to check for various common WordPress patterns whether they are included in the HTML string.
 163   * Since any of these actions may be disabled through third-party code, this function may also return null to indicate
 164   * that it was not possible to determine ownership.
 165   *
 166   * @since 5.7.0
 167   * @access private
 168   *
 169   * @param string $html Full HTML output string, e.g. from a HTTP response.
 170   * @return bool|null True/false for whether HTML was generated by this site, null if unable to determine.
 171   */
 172  function wp_is_local_html_output( $html ) {
 173      // 1. Check if HTML includes the site's Really Simple Discovery link.
 174      if ( has_action( 'wp_head', 'rsd_link' ) ) {
 175          $pattern = preg_replace( '#^https?:(?=//)#', '', esc_url( site_url( 'xmlrpc.php?rsd', 'rpc' ) ) ); // See rsd_link().
 176          return str_contains( $html, $pattern );
 177      }
 178  
 179      // 2. Check if HTML includes the site's REST API link.
 180      if ( has_action( 'wp_head', 'rest_output_link_wp_head' ) ) {
 181          // Try both HTTPS and HTTP since the URL depends on context.
 182          $pattern = preg_replace( '#^https?:(?=//)#', '', esc_url( get_rest_url() ) ); // See rest_output_link_wp_head().
 183          return str_contains( $html, $pattern );
 184      }
 185  
 186      // Otherwise the result cannot be determined.
 187      return null;
 188  }