<?php
/*
Plugin Name: Blogger To Wordpress Redirector
Plugin URI: http://www.devilsworkshop.org
Description: If you have imported your blog from blogspot then you might be redirecting visitors from your old blogspot blog to your new wordpress blogs HOMEPAGE. This plugin detect all such redirections and find one-to-one mapping between blogspot post and wordpress post. Then it redirect users to the same post on new wordpress blog for which they actually came looking for!
Version: 1.0 
Author: Rahul Bansal
Author URI: http://www.devilsworkshop.org
*/
?>

<?php
/*
Special Thanks to Charles [link: http://charles.gagalac.us/] 
He helped while debugging code on #wordpress IRC channel.
*/
?>

<?php
function rbBloggerToWordpress(){
//
//replace rb286.blogspot.com with your blogspot blogs address
//DO NOT remove quotes i.e " and "
//
$oldBlogURL = "rb286.blogspot.com";
global $wpdb;
//echo $oldBlogURL; 
//following is to avoid infinite redirection problem
if( strcmp( $_SERVER['REQUEST_URI'] , "/" ) == 0 ){
   //"We are on Index Page";
	$ref = $_SERVER['HTTP_REFERER'];
	$refarr = explode("/", $ref);

	if ($refarr[2] == $oldBlogURL ){
		$bloggerurl = '\/'.$refarr[3].'\/'.$refarr[4].'\/'.$refarr[5];
		$sqlstr = "
			    SELECT wposts.guid 
			    FROM $wpdb->posts wposts, $wpdb->postmeta wpostmeta
			    WHERE wposts.ID = wpostmeta.post_id 
			    AND wpostmeta.meta_key = 'blogger_permalink' 
			    AND wpostmeta.meta_value = '".$bloggerurl."'
			 ";             
		$wpurl = $wpdb->get_results($sqlstr, ARRAY_N);
		if ($wpurl){
			header( 'Location: '.$wpurl[0][0].' ') ;
                        exit;
		}
	}
  }
}
?>

<?php
add_action('wp_head','rbBloggerToWordpress');
?>