/miniebay

mini ebay auction in oTree

Primary LanguagePython

Mini ebay-like auction

UPDATE:

The code is now re-written so it works with new oTree (>2.5) and new Django Channels (2.x)/

Introduction

How does this thing work:

  1. We create a standard oTree app (ebay folder)
  2. We add its name to the settings.py as an oTree extension:
EXTENSION_APPS = ['ebay']

  1. In ebay folder we create another sub-folder named otree_extensions and we create two python files there:

    1. consumers.py
    2. routing.py

  2. routing defines what path the javascript on the page should 'knock to' to reach our python code (which is mostly located in consumers.py)

  3. consumers define our logic: it contains one class called EbayConsumer

The logic there is straightforward - as soon as someone connects, we get his/her group id, and player id and find these two objects on our database.

Then we add new connections to a special group that allows them to communicate in real time (in connect method).

receive method of EbayConsumer is executed every time we get a new message from the user. If it contains bid_up command then we send the information that current bid is increased to the entire group.

In other words we just call a new_bid method below, that:

  • updates a price for the group.
  • updates an information about the winner
  • Resets the counter till when the auction is over.
  • Sends this whole package to all group members.

A small piece of code based on channels to demonstrate how to create simple auctions in oTree

Filipp Chapkovski, Higher School of Economics, Moscow