Validates a URL for use in a redirect.
Description
Checks whether the $location is using an allowed host, if it has an absolute path. A plugin can therefore set or remove allowed host(s) to or from the list.
If the host is not allowed, then the redirect is to $fallback_url supplied.
Parameters
$location
stringrequired- The redirect to validate.
$fallback_url
stringoptional- The value to return if $location is not allowed.
Default:
''
Source
/**
* Validates a URL for use in a redirect.
*
* Checks whether the $location is using an allowed host, if it has an absolute
* path. A plugin can therefore set or remove allowed host(s) to or from the
* list.
*
* If the host is not allowed, then the redirect is to $fallback_url supplied.
*
* @since 2.8.1
*
* @param string $location The redirect to validate.
* @param string $fallback_url The value to return if $location is not allowed.
* @return string Redirect-sanitized URL.
*/
function wp_validate_redirect( $location, $fallback_url = '' ) {
$location = wp_sanitize_redirect( trim( $location, " \t\n\r\0\x08\x0B" ) );
// Browsers will assume 'http' is your protocol, and will obey a redirect to a URL starting with '//'.
if ( str_starts_with( $location, '//' ) ) {
$location = 'http:' . $location;
}
/*
* In PHP 5 parse_url() may fail if the URL query part contains 'http://'.
* See https://bugs.php.net/bug.php?id=38143
*/
$cut = strpos( $location, '?' );
$test = $cut ? substr( $location, 0, $cut ) : $location;
$lp = parse_url( $test );
// Give up if malformed URL.
if ( false === $lp ) {
return $fallback_url;
}
// Allow only 'http' and 'https' schemes. No 'data:', etc.
if ( isset( $lp['scheme'] ) && ! ( 'http' === $lp['scheme'] || 'https' === $lp['scheme'] ) ) {
return $fallback_url;
}
if ( ! isset( $lp['host'] ) && ! empty( $lp['path'] ) && '/' !== $lp['path'][0] ) {
$path = '';
if ( ! empty( $_SERVER['REQUEST_URI'] ) ) {
$path = dirname( parse_url( 'http://placeholder' . $_SERVER['REQUEST_URI'], PHP_URL_PATH ) . '?' );
$path = wp_normalize_path( $path );
}
$location = '/' . ltrim( $path . '/', '/' ) . $location;
}
/*
* Reject if certain components are set but host is not.
* This catches URLs like https:host.com for which parse_url() does not set the host field.
*/
if ( ! isset( $lp['host'] ) && ( isset( $lp['scheme'] ) || isset( $lp['user'] ) || isset( $lp['pass'] ) || isset( $lp['port'] ) ) ) {
return $fallback_url;
}
// Reject malformed components parse_url() can return on odd inputs.
foreach ( array( 'user', 'pass', 'host' ) as $component ) {
if ( isset( $lp[ $component ] ) && strpbrk( $lp[ $component ], ':/?#@' ) ) {
return $fallback_url;
}
}
$wpp = parse_url( home_url() );
/**
Changelog
Version | Description |
---|---|
2.8.1 | Introduced. |
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