Installation

Assuming Python’s pip is installed (for Debian-based systems, this can be installed with sudo apt-get install python-pip), alertscraper can be installed directly from PyPI:

pip install alertscraper

Python versions 3.3+ (and 2.6+) are supported and tested against.

Quick start

alertscraper is based on URLs, and maintains a history file for each URL that you scrape so it knows when something is new.

Start by navigating in your web-browser to the website you want to scrape, and then copying and pasting the URL. Then, inspect the page source of the site and see if you can figure out the DOM path to the relevant element. In this case, it was a li element with the class name result so the combined thing becomes li.result.

alertscraper 'https://some-site.org/?query=guitar&maxprice=550' li.result

This will download the given URL and list the text content of each item specified. This lets you know your query is correct.

Now we want to save this to a database file, that is, say that “I’ve seen everything currently posted and am only now interested in new stuff”.

alertscraper 'https://some-site.org/?query=guitar&maxprice=550' li.result --file=guitars.txt

Notice that it prints out again all the links it found. If we were to run the command again, it would not print them out since it will have stored them as “already seen”.

Finally, lets run the command to email us everything that has not yet been seen.

alertscraper 'https://some-site.org/?query=guitar&maxprice=550' li.result --file=guitars.txt --email=myemail@gmail.com

This only runs once. If you want it to run continually, I’d recommend putting it in a cronjob. Eventually I may add a daemon mode, but this is good for now.

Happy scraping!