This is a small project monitoring the change of the average price of current humble bundles. Usually the average price rises during the two weeks a bundle is active. I started developing this project after I discovered that the average price was falling in one case and I was interested in how often this happens.
Here you can see the live results.
This repository should contain all files to set this up on your own. It's cobbled up and hacky - sorry about that. Feel free to improve it, clean it up, and create a pull request. ;-)
The paths in the scripts assume that you have to following structure in your home:
graphs/humble
├── do_plot
├── fetch_humble_stats.pl
├── get_data
├── plot.gp
├── run_update_current_bundles
├── stats
└── update_current_bundles.rb
html/graphs/humble
└── index.php
Where the directory html is accessible from the web and your crontab contains the following entries:
*/1 * * * * ~/graphs/humble/get_data
*/20 * * * * ~/graphs/humble/do_plot
*/20 * * * tue ~/graphs/humble/run_update_current_bundles
On a Tuesday every 20 minutes run_update_current_bundles is being called. This script calls update_current_bundles.rb with the correct parameters and environment variables set.
update_current_bundles.rb gets the home page of Humble Bundle and parses it for the names of the current bundles and writes them to graphs/humble/current_bundles.
Every minute the cronjob calls get_data. This calls fetch_humble_stats.pl for every line in current_bundles and redirects the output to appropriate file in graphs/humble/stats/.
This perl script gets an url to the pubnub service for live updates about the humble bundle stats. The service returns a json that is being parsed and printed to stdout.
The data is being plotted every 20 minutes by do_plot which calls gnuplot for every current bundle. How the plot looks like is defined in plot.gp.