<?php
/**
* HTTPS detection functions.
*
* @package WordPress
* @since 5.7.0
*/
/**
* Checks whether the website is using HTTPS.
*
* This is based on whether both the home and site URL are using HTTPS.
*
* @since 5.7.0
* @see wp_is_home_url_using_https()
* @see wp_is_site_url_using_https()
*
* @return bool True if using HTTPS, false otherwise.
*/
function wp_is_using_https() {
if ( ! wp_is_home_url_using_https() ) {
return false;
}
return wp_is_site_url_using_https();
}
/**
* Checks whether the current site URL is using HTTPS.
*
* @since 5.7.0
* @see home_url()
*
* @return bool True if using HTTPS, false otherwise.
*/
function wp_is_home_url_using_https() {
return 'https' === wp_parse_url( home_url(), PHP_URL_SCHEME );
}
/**
* Checks whether the current site's URL where WordPress is stored is using HTTPS.
*
* This checks the URL where WordPress application files (e.g. wp-blog-header.php or the wp-admin/ folder)
* are accessible.
*
* @since 5.7.0
* @see site_url()
*
* @return bool True if using HTTPS, false otherwise.
*/
function wp_is_site_url_using_https() {
/*
* Use direct option access for 'siteurl' and manually run the 'site_url'
* filter because `site_url()` will adjust the scheme based on what the
* current request is using.
*/
/** This filter is documented in wp-includes/link-template.php */
$site_url = apply_filters( 'site_url', get_option( 'siteurl' ), '', null, null );
return 'https' === wp_parse_url( $site_url, PHP_URL_SCHEME );
}
/**
* Checks whether HTTPS is supported for the server and domain.
*
* This function makes an HTTP request through `wp_get_https_detection_errors()`
* to check for HTTPS support. As this process can be resource-intensive,
* it should be used cautiously, especially in performance-sensitive environments,
* to avoid potential latency issues.
*
* @since 5.7.0
*
* @return bool True if HTTPS is supported, false otherwise.
*/
function wp_is_https_supported() {
$https_detection_errors = wp_get_https_detection_errors();
// If there are errors, HTTPS is not supported.
return empty( $https_detection_errors );
}
/**
* Runs a remote HTTPS request to detect whether HTTPS supported, and stores potential errors.
*
* This function checks for HTTPS support by making an HTTP request. As this process can be resource-intensive,
* it should be used cautiously, especially in performance-sensitive environments.
* It is called when HTTPS support needs to be validated.
*
* @since 6.4.0
* @access private
*
* @return array An array containing potential detection errors related to HTTPS, or an empty array if no errors are found.
*/
function wp_get_https_detection_errors() {
/**
* Short-circuits the process of detecting errors related to HTTPS support.
*
* Returning a `WP_Error` from the filter will effectively short-circuit the default logic of trying a remote
* request to the site over HTTPS, storing the errors array from the returned `WP_Error` instead.
*
* @since 6.4.0
*
* @param null|WP_Error $pre Error object to short-circuit detection,
* or null to continue with the default behavior.
*/
$support_errors = apply_filters( 'pre_wp_get_https_detection_errors', null );
if ( is_wp_error( $support_errors ) ) {
return $support_errors->errors;
}
$support_errors = new WP_Error();
$response = wp_remote_request(
home_url( '/', 'https' ),
array(
'headers' => array(
'Cache-Control' => 'no-cache',
),
'sslverify' => true,
)
);
if ( is_wp_error( $response ) ) {
$unverified_response = wp_remote_request(
home_url( '/', 'https' ),
array(
'headers' => array(
'Cache-Control' => 'no-cache',
),
'sslverify' => false,
)
);
if ( is_wp_error( $unverified_response ) ) {
$support_errors->add(
'https_request_failed',
__( 'HTTPS request failed.' )
);
} else {
$support_errors->add(
'ssl_verification_failed',
__( 'SSL verification failed.' )
);
}
$response = $unverified_response;
}
if ( ! is_wp_error( $response ) ) {
if ( 200 !== wp_remote_retrieve_response_code( $response ) ) {
$support_errors->add( 'bad_response_code', wp_remote_retrieve_response_message( $response ) );
} elseif ( false === wp_is_local_html_output( wp_remote_retrieve_body( $response ) ) ) {
$support_errors->add( 'bad_response_source', __( 'It looks like the response did not come from this site.' ) );
}
}
return $support_errors->errors;
}
/**
* Checks whether a given HTML string is likely an output from this WordPress site.
*
* This function attempts to check for various common WordPress patterns whether they are included in the HTML string.
* Since any of these actions may be disabled through third-party code, this function may also return null to indicate
* that it was not possible to determine ownership.
*
* @since 5.7.0
* @access private
*
* @param string $html Full HTML output string, e.g. from a HTTP response.
* @return bool|null True/false for whether HTML was generated by this site, null if unable to determine.
*/
function wp_is_local_html_output( $html ) {
// 1. Check if HTML includes the site's Really Simple Discovery link.
if ( has_action( 'wp_head', 'rsd_link' ) ) {
$pattern = preg_replace( '#^https?:(?=//)#', '', esc_url( site_url( 'xmlrpc.php?rsd', 'rpc' ) ) ); // See rsd_link().
return str_contains( $html, $pattern );
}
// 2. Check if HTML includes the site's REST API link.
if ( has_action( 'wp_head', 'rest_output_link_wp_head' ) ) {
// Try both HTTPS and HTTP since the URL depends on context.
$pattern = preg_replace( '#^https?:(?=//)#', '', esc_url( get_rest_url() ) ); // See rest_output_link_wp_head().
return str_contains( $html, $pattern );
}
// Otherwise the result cannot be determined.
return null;
}