bottrop.php, a simple MediaWiki spam trap.

bottrop.php is a simple spam trap for MediaWiki based web sites. As long as your site is not really big, and as long as spammers do not wisen up to the kind of trick it uses, it provides pretty much 100% effective spam blocking, without annoying most users. (Users with a browser modern enough to understand CSS, which are most probably most of your users, won’t even notice any change to the site.)

It stops spam bots from working by adding two hidden form fields, one of must never contain anything, and the other must contain a specified string. If the never-fill field is filled, or the must-fill field has a wrong or no value set, the post is rejected. This method is used on a number of other apps as well, and has proven to be quite effective. On tanasinn.info, we haven’t seen a single spam edit since we began using this extension.

Changelog

1.1: Enabled for logged-in users due to problems with spambots that register first.
1.0: Initial release.

How to use

Download bottrop.txt. Place it into the “extensions” folder in your MediaWiki install directory. Rename it to “bottrop.php”
Edit the two configuration values in “bottrop.php” ($bottrop_field_name and $bottrop_field_value). Use something random, but stick to lower/uppercase chars and underscores unless you know what you are doing.
Activate the extension by adding the line
```
require_once( "$IP/extensions/bottrop.php" );
```
at the end of the file “LocalSettings.php” in your MediaWiki install directory.
Make an edit to verify it did not break stuff.

Should it not work, please tell me so I can fix it.