Fix wordpress serialized variables in custom meta data when running a migration

wp-fix-meta-serialization.php

<?php
/*
*  Wordpress postmeta find&replace code 
*  
*  This file should be run on your source database to echo out update statements to run on your migrated database.
*  It is to address the issue of when doing a find/replace on an sql file during a wordpress migration, that breaks
*  any content changed within wordpress serialized meta values, particularly if you have custom post types etc.
*  
*  Do your normal find/replace over the exported sql, import it into your new database, then run this code and copy the resulting
*  update SQL into your new database to fix it.
*
*  See line 80 ish for where to actually define your find/replace.
*
*/



error_reporting(-1);

$dbhost = '';
$dbname = '';
$dbuser = '';
$dbpass = '';

$postmeta_table = 'wp_postmeta';


$dbconn = mysql_connect($dbhost, $dbuser, $dbpass);
mysql_select_db($dbname, $dbconn);

$result = selectarray('SELECT * FROM wp_postmeta');


if (is_array($result)){
	
	foreach($result as $row){
	
		$meta_id = $row['meta_id'];
		$meta_value = $row['meta_value'];
		if (is_serialized($meta_value)){
		
			$new_meta_value = make_new_value($meta_value);
			
			if (strlen($new_meta_value) != strlen($meta_value)) {
			
				ob_start();
				echo($meta_value."<br>".strlen($meta_value)."<br><br>".$new_meta_value."<br>".strlen($new_meta_value)."<br>");
				echo("<br><hr><hr><br>");
				@$debug .= ob_get_clean();
				
				
				$sql .= "
UPDATE wp_postmeta SET meta_value = '".mysql_real_escape_string($new_meta_value)."' WHERE meta_id = '$meta_id';
						";
				
				

			}
		}
	}
	
}

echo("<pre>$sql</pre>");




function is_serialized($v){
	
	return @unserialize($v)?true:false;
	
}


function make_new_value($oldvalue){
	$val_a = unserialize($oldvalue);
	
	if (is_array($val_a) && count($val_a)) {
		foreach($val_a as &$val){
		
			//run your find & replace code here
			//e.g:
			$val = str_replace('findme', 'replacemewith', $val);
			
		}
	
		$new_val_ser = serialize($val_a);
		
		
		return $new_val_ser;

	} else {
		
		return $oldvalue;
	}
	
}

function selectarray($sql) {
	
	
	
	$result = mysql_query($sql) or die(mysql_error());
	
	if (!$result) {
		debug(mysql_error());
	}
	
	$table_result=array();
    $r=0;
    while($row = mysql_fetch_assoc($result)){
        $arr_row=array();
        $c=0;
        while ($c < mysql_num_fields($result)) {       
            $col = mysql_fetch_field($result, $c);   
            $arr_row[$col -> name] = $row[$col -> name];           
            $c++;
        }   
        $table_result[$r] = $arr_row;
        $r++;
    }   
    
	
	return $table_result;

	
}




?>