Introduction

What is ksiemgowy?

Ksiemgowy is a tool used for bookkeeping of membership dues in Hakierspejs, a hackerspace in Łódź, Poland. Long story short, one day we decided to start collecting dues in order to build up some money that would eventually let us rent our headquarters. At the same time, we didn’t want to spend too much time pinging people who are overdue and reporting organization’s current financial situation. Because of that, we decided to create software that would automate the main activities related to handling dues.

The system was built with the following goals in mind:

  • transparency: everyone should have access to current information about the status of fundraising,

  • privacy: the information should be reasonably anonymized, e.g. aggregated in a way that would make it difficult to de-anonymize,

  • automation: ideally, the person managing the account should be able to take some time off on holidays and the system should operate normally,

  • good feedback: the system should notify organization members once they are overdue or once a payment has been accounted for.

How does ksiemgowy work?

Every program attempts to expand until it can read mail. Those programs which cannot so expand are replaced by ones which can.

Jamie Zawinski

Most hackerspaces solve the problem of bookkeeping with the aid of screen scraping, but the author was worried about raising eyebrows when their program automatically logged in to the bank using a script. Because of that, it was decided to look for passive ways of detecting that a transfer was mode.

mBank, the bank in which Hakierspejs has an account, has daily billing updates, which is a perfect match for this scenario. Should this feature be enabled, account owner receives daily updates on which transactions took place. Given that this includes all incoming and outcoming transfers related to the bank account, it is a reasonably reliable way to estimate the current balance and detect who transferred the money. The act of viewing the e-mail is not possible to observe, which means that we are probably at a lower risk of getting our account locked.

Another way to think of ksiemgowy is as of a stateful email-to-email bot: it reads mail and sends mail. All e-mails relevant to ksiemgowy’s operation are parsed and logged in a database, which enables it to send notifications about overdue payments.