There are one to two main branches of the bot:

• The master code is implemented at https://tools.wmflabs.org/citations/, and is intended for public use.
• When needed, the development branch is intended for major restructuring and testing, and is implemented at https://tools.wmflabs.org/citations-dev/ .

This is some basic documentation about what this bot is and how some of the parts connect.

This is more properly a bot-gadget-tool combination. The parts are:

• DOIBot, found in index.html (web frontend) and process_page.php (information is POSTed to this and it does the citation expansion; backend). This automatically posts a new page revision with expanded citations and thus requires a bot account. All activity takes place on Tool Labs.
• Citation expander (:en:Mediawiki:Gadget-citations.js) + gadgetapi.php. This is comprises an Ajax front-end in the on-wiki gadget and a PHP backend API.
• Generic template creates the wiki reference given an identifier (for example given a doi: https://tools.wmflabs.org/citations/generate_template.php?doi=10.1109/SCAM.2013.6648183)

Bugs and requested changes are listed here: https://en.wikipedia.org/wiki/User_talk:Citation_bot .

Basic structure of a Citation bot script:

• define configuration constants
• require expandFns.php, which will set up the rest of the needed functions
• use Page functions to fetch/expand/post the page's text

A quick tour of the main files:

• constants.php: constants defined
• wikiFunctions.php: functions related to Wikipedia ineractions, including some marked as "untested".
• WikipediaBot.php: functions to facilitate HTTP access to the Wikipedia API.
• DOItools.php: defines text/name functions
• expandFns.php: sets up needed functions, requires most of the other files listed here
• apiFunctions.php: sets up needed functions

Class files:

• Page.php: Represents an individual page to expand citations on. Key methods are Page::get_text_from(), Page::expand_text(), and Page::write().
• Template.php: most of the actual expansion happens here. Template::add_if_new() is generally (but not always) used to add parameters to the updated template; Template::tidy() cleans up the template, but may add parameters as well and have side effects.
• Comment.php: Handles comments, nokwiki, etc. tags
• Parameter.php: contains information about template parameter names, values, and metadata, and methods to parse template parameters.

Constants and definitions should be provided in constants.php. Classes should be in individual files. The code is generally written densely. Beware assignments in conditionals, one-line if/foreach/else statements, and action taking place through method calls that take place in assignments or equality checks. Also beware the difference between else if and elseif.

The bot requires php >= 5.6, whereas the WMFlabs servers by default (as of 2018) run 5.5.9. To access php5.6, one must run the bot as a webservice:

become citations[-dev]
webservice stop
webservice --backend=kubernetes php5.6 start

Or for testing in the shell:

webservice --backend=kubernetes php5.6 shell

Before entering the k8s shell, it may be necessary to install phpunit (as wget is not available in the k8s shell):

wget https://phar.phpunit.de/phpunit-5.phar
webservice --backend=kubernetes php5.6 shell
php phpunit-5.phar --bootstrap expandFns.php tests/phpunit/TemplateTest.php