alertscraper
============
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:alt: alertscraper badge
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.. figure:: https://travis-ci.org/michaelpb/alertscraper.png?branch=master
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General purpose flexible tool for scraping a given URL for a certain
type of items, and then email if new items are added. Useful for
monitoring ad or auction websites. Could also be useful for setting up
email alerts on your own site.
WARNING
=======
- Check the Terms of Service of the site before you use this tool! For
some sites, using this tool may violate their terms of service, and
should not be used.
Limitations
===========
- This code ONLY scrapes based on the initial HTTP request. Websites
that function as single-page apps will not work. This could be
supported in the future using JSON, or integrating with something
heavier weight like Selenium.
Usage
=====
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!
Contributing
============
- `CONDUCT.md <CONDUCT.md>`__
New features, tests, and bug fixes are welcome!
