Extension:AssertEdit


 * Help your bots to help your wiki.

When I started working with bots, I realised the potential for a simple operator error to make a lot of bad edits; such as a bot intended to run on a test wiki accidently running on wikipedia, because someone forgot to supply the  option. It also happens that a bot may get logged out, and unknowingly continue editing anonymously, without the bot flag, until it's blocked.

It's not easy for a bot to determine whether it is logged in, without some server side support. Unfortunately, no such support was available, until now.

How it works
When editing, the bot would add an assertion to the URL. If this assertion succeeds, the extension does nothing, and the edit proceeds as normal. If the assert fails, the extension replaces the normal edit interface with a simple error message. The bot could detect this message, and display an error to the operator; but even a bot that didn't look for that would fail in an obvious fashion, preventing the bad edit from occurring.

This is done simply by adding  or   to the end of the URL. assert ensures that assertion is positive, while nassert ensures it is negative. Unrecognized assertions will always fail, whether assert or nassert is used, allowing mistyped assertions to be discovered quickly. Additionally, sites may add their own assertions, so that local bots won't accidently hit other sites.

If both a positive and negative assertion are specified, then both must succeed. For example, action=edit&assert=bot&nassert=exists would fail if the bot gets logged out or tries to edit a preexisting page.

Downloading
svn checkout http://svn.wikimedia.org/svnroot/mediawiki/trunk/extensions/AssertEdit/
 * To download this, issue the following shell command:

Installation
To install this, download the AssertEdit.php file, place is in ./extensions/AssertEdit/, then add a line to your LocalSettings.php like

New asssertions can then be added with, where key is the name of the assertion, and value is its value; true means the assertion will succeed, false will fail.

value must either be a boolean (true or false) or a function (as defined by the PHP is_callable function) which returns a boolean value.

AssertEdit::setAssert will fail value is the wrong type, or key corresponds to an assertion that cannot be overridden.