<?php
// Script to fix serialized strings directly with DB access

$host = '';
$db = '';
$user = '';
$pass = '';

$table = '';
$column = '';

$collation = 'utf8';

// End tunables

function serialize_fix_callback($match) {
   if (function_exists('mb_strlen')) {
      return 's:' . mb_strlen($match[2]);
   } else {
      return 's:' . strlen($match[2]);
   }
}

$con = mysqli_connect($host, $user, $pass);
if (!$con){
   die('Could not connect: ' . mysqli_error($con));
}
mysqli_select_db($con, $db);
mysqli_query($con, "SET NAMES $collation");

$query = "SELECT `$column` FROM `$table`";
$result = mysqli_query($con, $query);

while ($row = mysqli_fetch_row($result)) {
   // Try single string
   $new = preg_replace_callback(
      '!^s:(\d+)(?=:"(.*?)";$)!s',
      'serialize_fix_callback',
      $row[0]
   );
   if ($new === $row[0]) {
      // Try nested strings
      $new = preg_replace_callback(
         '!(?<=^|;)s:(\d+)(?=:"(.*?)";(?:}|a:|s:|b:|d:|i:|o:|N;))!s',
         'serialize_fix_callback',
         $row[0]
      );
   }

   if ($new !== $row[0]) {
      if (@unserialize($row[0])) {
         // Sanity check, don't clobber if already valid
         echo "[Skipping] {$row[0]}\n";
      } elseif (@unserialize($new)) {
         // New data is valid, save
         echo "[Fixing] {$row[0]}\n";
         $query = "UPDATE `$table` SET ".
            "`$column` = '".mysqli_real_escape_string($con, $new)."' WHERE ".
            "`$column` = '".mysqli_real_escape_string($con, $row[0]).
            "'";

         if (!mysqli_query($con, $query)) {
            die(mysqli_error($con));
         }
      } else {
         // Neither old nor new data is valid
         echo "[Failed] {$row[0]}\n";
      }
   }
}

// vim: sw=3 ts=3 ai et