While working on a project, I stumbled into some of the weirdest Apache2 mod_rewrite problems that I’d ever seen.
The goal was to make a URL like http//www.nowhere.com/item/1234 turn into http://www.nowhere.com/item.php?id=1234. Trivial, and I’ve done it all the time.
RewriteEngine on
RewriteRule ^item/(.+)$ item.php?id=$1 [L]
This time it wasn’t working the way I expected. When I used the human-readable version, my page got delivered by I had no images, no css, no javascript. Yet, if I used the computer-friendly long form with parameters, it worked just fine.
A little examination with Safari’s activity window showed me that in the initial case the browsers were looking at all relative URLs as if they were prefixed with /item/. This make sense, because the URL redirect knows how to play rewrite games with the rules to get to my page, but the relative links on those pages, to css, graphics, and js, had no clue this was a fake base url.
Many thanks to richardk who pointed out multiple solutions back in 2005.
- Don’t use /, and there isn’t a problem.
- Use absolute paths, though you have to edit all the links on your page; if using PHP, consider a variable for the base path.
- Use a RewriteRule to hack off the offensive directory that doesn’t exist.
- Or, use the <BASE …> tag.
Well, that rendered the page prettier, but I realized my argument wasn’t being passed in. Yet, the re-write rule was correct.
So I tried http//www.nowhere.com/item, which should not have matched and should not have brought up a page. Yet it did.
A little experimentation showed that any page that had a known extension was getting delivered.
What this meant was that the moment the browser saw /item it found the item.php page and delivered it without ever going through Apache’s rewrite module, and hence no parameters.
Luckily, I’ve encountered this symptom before in a different context. The offender: MultiViews. This is the bugger that deals with multiple language support; you know, where you have a zillion internationalized instances based on filename extensions….
Turning that off instantly solved the problem of delivering a file without an extension:
# Options Indexes FollowSymLinks MultiViews
Options Indexes FollowSymLinks
That also meant that the mod-rewrite rules worked. And that meant the parameters were passed correctly. And that meant I was was happy, because the code was working.