Why does the Passenger/mod_rails documentation ask me to explicitly disable MultiViews?

Question

From the documentation:

<VirtualHost *:80>
    ServerName www.mycook.com
    DocumentRoot /webapps/mycook/public
    <Directory /webapps/mycook/public>
        Allow from all
        Options -MultiViews
    </Directory>
</VirtualHost>

So why the following line?

Options -MultiViews

I understand, coarsely, how MultiViews works, and frankly, I don't understand why anybody would use it. Nevertheless, I don't see why the Passenger configuration guide sees it as so important to explicitly disable the option in the site configuration.

Can anyone shed light on the situation?

Answer 1

I am not familiar with Rails, but in general, MultiViews enabled can lead to funny behaviour in certain situations - most commonly, it can end up serving a page when an incorrect URL is entered, instead of returning a 404 as it should.

Here is a blog post on another subtle possible problem with MultiViews.

This GoDaddy blog entry points out another problematic consequence:

Script files are of particular concern. Say you have an old version of a script.pl file that you copy to script.pl.bak for backup purposes. A request for script.pl.bak will still be interpreted by Apache as a Perl script, causing the old version of your code to be executed! One can imagine other instances where a script file may be executed unintentionally because of this behavior by Apache.

Bottom line, Multiviews are fine for collections of static HTML pages, but not really a good thing to have in an environment with rewritten URLs.