After seeing Daniel Crowley's entertaining talk at ShmooCon 2011 on URL shorteners, I'd wanted to put together something to do some URL grinding and harvesting myself. Which led to this project. Because people use URL shortening services without realizing that things they shorten can be easily discovered (the services do not promise or even suggest that they provide privacy, this isn't their fault), there's a lot of stuff out there.

At this point, the project is probably not terribly accurately named - it supports pretty much any kind of URL shortening/redirection service. In the current state, it basically works by passing a URL to the grinder, and the grinder then tries every iteration created by fuzzing the last two characters. By default, tries upper and lowercase letters and digits. You can change this by altering CHARSET.

The grinder will try every URL in sequence, and it will track every URL it encounters during resolution. It also tracks the status code encountered when retrieving the final URL in the resolution process. It will follow as many redirections as it encounters starting with the base URL. It also tracks the content-type obtained at the final URL in the resolution process.

Results are stored in an SQLite database, named bitly-grinder.db in the same directory as the script is run from.

Results can be browsed via the embedded simple HTTP server, which runs on port 8000 by default. Just run grinder_http_server.py and then browse to http://localhost:8000. The following paths exist by default:

• / -- (or any unknown URL) Displays URLs and all paths in the resolution process that ultimately resulted in status 200.
• /all -- Displays every result obtained.
• /nonhtml -- Displays only results that were valid (status 200) and not of content-type text/html
• /nonhtml-all -- Displays all results with content-type other than text/html, regardless of status.
• /images -- Displays all images that were found.

• DictShield -- DictShield, an awesome library that provides typed dictionary support and object modeling/validation.

I've thought of a number of random things that would be cool to add to the project at some point. If you've got more or you're interested in contributing, please get in touch with me.

• Extend the HTTP server for result browsing, possibly with an AJAXy UI
• Provide statistics on what sites have the most shortened URLs
• Track history - resolution path + destination URLs over time
• Some kind of remote control mechanism, so that grinding can be distributed across a number of remote nodes, e.g. AWS.
• Randomization of grinding URLs