Differ is a Python-based tool that will check specified web pages at specified intervals, and email the user the differences between checks (if any are found).

• Python 2.7+
• Redis
• Celery
• Requests
• Beautiful Soup
• Supervisor

You'll also need a place to host this (and/or a Heroku account), a Mandrill account, and a webpage (or any HTML document) that you want to monitor.

You can run this app in one of two ways: as a stand-alone command (handy to do manual site diffs or join up with a Cron task or Herou's Scheduler), or as a scheduled process via Celery.

First off, you're doing this in a virtual environment, right? So make sure you've set that up properly:

virtualenv differ-venv --distribute
source ./differ-venv/bin/activate

Then install your dependancies:

pip install -r requirements.txt

Run the full task thusly:

python app.py

The output from this task will go to stdout, and if an email is specified, the differences will be emailed!

Start the worker:

celery -A offline.tasks worker --config=offline.celeryconfig --loglevel=info

Start the scheduler:

celery beat --config="offline.celeryconfig" --loglevel="info" --schedule="/tmp/celerybeat_schedule.db"

And as with all background processes, you'll probably want to daemonize Celery, and then run it via Supervisord (or init.d, launchd, etc.).

Rather than running workers and the beat task, run a single worker in beat mode (if you know this will only ever be one worker — especially handy for running on services like Heroku). This way, you can run everything with one command:

celery -A offline.tasks worker --config=offline.celeryconfig --loglevel=info -B

• Better document email functionality.
• Create example using MongoDB (or Postgres) in addition to Redis.
• Add a web panel for adding further scraping targets.

First release! Woot!

This project was developed by Mike Dory. Pull requests are welcome, as are bugs, feature requests, and general suggestions, so fire away. =)