<?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.

 *

 * @since 5.7.0

 *

 * @return bool True if HTTPS is supported, false otherwise.

 */

function wp_is_https_supported() {

	$https_detection_errors = get_option( 'https_detection_errors' );

	// If option has never been set by the Cron hook before, run it on-the-fly as fallback.

	if ( false === $https_detection_errors ) {

		wp_update_https_detection_errors();

		$https_detection_errors = get_option( 'https_detection_errors' );

	}

	// If there are no detection errors, HTTPS is supported.

	return empty( $https_detection_errors );

}

/**

 * Runs a remote HTTPS request to detect whether HTTPS supported, and stores potential errors.

 *

 * This internal function is called by a regular Cron hook to ensure HTTPS support is detected and maintained.

 *

 * @since 5.7.0

 * @access private

 */

function wp_update_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 5.7.0

	 *

	 * @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_update_https_detection_errors', null );

	if ( is_wp_error( $support_errors ) ) {

		update_option( 'https_detection_errors', $support_errors->errors );

		return;

	}

	$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.' ) );

		}

	}

	update_option( 'https_detection_errors', $support_errors->errors );

}

/**

 * Schedules the Cron hook for detecting HTTPS support.

 *

 * @since 5.7.0

 * @access private

 */

function wp_schedule_https_detection() {

	if ( wp_installing() ) {

		return;

	}

	if ( ! wp_next_scheduled( 'wp_https_detection' ) ) {

		wp_schedule_event( time(), 'twicedaily', 'wp_https_detection' );

	}

}

/**

 * Disables SSL verification if the 'cron_request' arguments include an HTTPS URL.

 *

 * This prevents an issue if HTTPS breaks, where there would be a failed attempt to verify HTTPS.

 *

 * @since 5.7.0

 * @access private

 *

 * @param array $request The Cron request arguments.

 * @return array $request The filtered Cron request arguments.

 */

function wp_cron_conditionally_prevent_sslverify( $request ) {

	if ( 'https' === wp_parse_url( $request['url'], PHP_URL_SCHEME ) ) {

		$request['args']['sslverify'] = false;

	}

	return $request;

}

/**

 * 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 false !== strpos( $html, $pattern );

	}

	// 2. Check if HTML includes the site's Windows Live Writer manifest link.

	if ( has_action( 'wp_head', 'wlwmanifest_link' ) ) {

		// Try both HTTPS and HTTP since the URL depends on context.

		$pattern = preg_replace( '#^https?:(?=//)#', '', includes_url( 'wlwmanifest.xml' ) ); // See wlwmanifest_link().

		return false !== strpos( $html, $pattern );

	}

	// 3. 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 false !== strpos( $html, $pattern );

	}

	// Otherwise the result cannot be determined.

	return null;

}