[Plugin: W3 Total Cache] index.html 404 error gets cached

It seems that WordPress doesn’t handle the URL http://example.com/index.html on an unmodified install (I’ve confirmed this on a handful of other WordPress sites along with my own). This is significant because index.html is a special file on many web-servers, often being the “home” page of a directory on the server. Without special handling, a request for index.html on a WordPress installation generates a 404 (file not found) error — which is obviously something we don’t want our visitors to be presented with.

Yesterday an unlikely combination of factors resulted in my 404 error page replacing my home page for a complete cache cycle. It went something like this:

• cached “home” page expires
• next “home” page request is for http://example.com/index.html
• index.html file request results in a 404 error
• 404 error page is cached
• all subsequent requests for http://example.com/ — and other “home” page URLs — return the cached 404 error page until the cache is next invalidated

There are two things that shouldn’t have happened here.

1. Requests for index.html should not result in 404 errors.
2. Error pages should never be cached.

The first can be addressed by adding the following code to the beginning of WordPress’ 404.php file:

<?php
	if ($_SERVER['REQUEST_URI'] == '/index.html') { header("Location: http://example.com/"); exit; }
?>

The second needs to be addressed within W3TC.

http://wordpress.org/extend/plugins/w3-total-cache/