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wp_check_invalid_utf8( string $string, bool $strip = false )

Checks for invalid UTF8 in a string.

Description

Parameters

$string

(string) (Required) The text which is to be checked.

$strip

(bool) (Optional) Whether to attempt to strip out invalid UTF8. Default is false.

Default value: false

Return

(string) The checked text.

Source

File: wp-includes/formatting.php

function wp_check_invalid_utf8( $string, $strip = false ) {
	$string = (string) $string;

	if ( 0 === strlen( $string ) ) {
		return '';
	}

	// Store the site charset as a static to avoid multiple calls to get_option()
	static $is_utf8 = null;
	if ( ! isset( $is_utf8 ) ) {
		$is_utf8 = in_array( get_option( 'blog_charset' ), array( 'utf8', 'utf-8', 'UTF8', 'UTF-8' ) );
	}
	if ( ! $is_utf8 ) {
		return $string;
	}

	// Check for support for utf8 in the installed PCRE library once and store the result in a static
	static $utf8_pcre = null;
	if ( ! isset( $utf8_pcre ) ) {
		$utf8_pcre = @preg_match( '/^./u', 'a' );
	}
	// We can't demand utf8 in the PCRE installation, so just return the string in those cases
	if ( ! $utf8_pcre ) {
		return $string;
	}

	// preg_match fails when it encounters invalid UTF8 in $string
	if ( 1 === @preg_match( '/^./us', $string ) ) {
		return $string;
	}

	// Attempt to strip the bad chars if requested (not recommended)
	if ( $strip && function_exists( 'iconv' ) ) {
		return iconv( 'utf-8', 'utf-8', $string );
	}

	return '';
}

Changelog

Version Description
2.8.0 Introduced.

© 2003–2019 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/wp_check_invalid_utf8