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

In this article

Checks for invalid UTF8 in a string.

Parameters

$textstringrequired
The text which is to be checked.
$stripbooloptional
Whether to attempt to strip out invalid UTF8.

Default:false

Return

string The checked text.

Source

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

	if ( 0 === strlen( $text ) ) {
		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' ), true );
	}
	if ( ! $is_utf8 ) {
		return $text;
	}

	// 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 ) ) {
		// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
		$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 $text;
	}

	// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- preg_match fails when it encounters invalid UTF8 in $text.
	if ( 1 === @preg_match( '/^./us', $text ) ) {
		return $text;
	}

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

	return '';
}

Changelog

VersionDescription
2.8.0Introduced.

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