Fix serialized data broken due to editing MySQL database in a text editor?

Question

Background: I downloaded a *.sql backup of my WordPress site\'s database, and replaced all instances of the old database table prefix with a new on

Answer 1

If the error is due to the length of the strings being incorrect (something I have seen frequently), then you should be able to adapt this script to fix it:

foreach($strings as $key => $str)
{
    try {
        unserialize($str);
    } catch(exception $e) {
        preg_match_all('#s:([0-9]+):"([^;]+)"#',$str,$m);
        foreach($m[1] as $k => $len) {
            if($len != strlen($m[2][$k])) {
                $newstr='s:'.strlen($m[2][$k]).':"'.$m[2][$k].'"';
                echo "len mismatch: {$m[0][$k]}\n";
                echo "should be:    $newstr\n\n";
                $strings[$key] = str_replace($m[0][$k], $newstr, $str);
            }
        }
    }
}