escape-string-xpath.php

<?php

// Escapes a string (if needed) using the concat function for its use
// in xpath expressions.
// Example:
//   $xpath = '/*[@value=' . escape_string_xpath("this is "foo's\"!") . ']';
// Becomes:
//   /*[@value=concat('this is "foo', "'", 's"!')]

function escape_string_xpath($value) {
    if (strpos($value, '"') === false) {
        return '"' . $value . '"';
    } else if (strpos($value, "'") === false) {
        return "'" . $value . "'";
    }

    return 'concat("' . str_replace('"', '", \'"\', "', $value) . '")';
}