Now that I migrated to WordPress for blogging, the permalinks of my previous blog entries have changed.
My initial idea was to use mod_rewrite by adding a RewriteRule for each old link redirecting to the new location, but that looked like a lot of copy&paste to me and would not teach me anything new.
Instead, I chose to redirect requests for old links to the WordPress search page. Try it out yourself: Click on this old permalink /article_php_5_enterprise_edition_available_online and you will be redirected to the search page, which displays the blog entry to you as a search result. This looks like a more flexible solution to me, just in case that my permalinks might change again one day.
The implementation was simple. I added a few lines of PHP code to the 404.php page of my WordPress theme as described in the support topic 404 Search Function for WordPress. I also added a header redirect directive.
This is the full code:
// Adjust if WordPress is located in subdirectory,
// e.g. http://www.example.com/weblog. Otherwise leave empty.
$blog_uri = ‘weblog';
// Don’t change from here.
$search_url = $blog_uri.’/?s=';
$search_term = urldecode( substr($_SERVER[‘REQUEST_URI’],1) );
$find = array(“‘”.$blog_uri.”‘”, “‘/'”, “‘[-/_]'”) ;
$replace = ” ” ;
$new_search = preg_replace($find, $replace, $search_term);
$new_search = urlencode($new_search);
// Redirect to search page.
Notice that for security reasons, I use urlencode() for the search page URL to avoid HTTP Response Splitting.