My friend Eliot has been running a retweet bot named @SanMo for some time that is designed to serve Twitter users in the Santa Monica, California area by allowing them to broadcast tweets to other Santa Monica-area users without explicitly friending them. He wrote up the full details of the service and the script behind it on his blog, and after reading about it, I wanted to start a similar service for Twitterers in my immediate vicinity.

After grabbing a copy of the code running @SanMo, (it’s the same Perl script created to power @lotd, available here), I quickly decided that I would rather write my own, for three reasons:

• Strike 1: It was written in Perl.
• Strike 2: It didn’t implement a feature that links the retweet to the original tweet.
• Strike 3: It required MySQL – a bit much for simple bot.
• Bonus Strike 4: It was written in Perl.

I sought out to write a lightweight script that would accomplish the same end goal (republishing tweets directed at a given account), and I’m happy to say that it’s finished: retweet.py has been running smoothly for the past few weeks behind the Twitter account SWMetro, a service for Twitter users in the southwest metro area of the Twin Cities.

It’s 40 lines of Python (if you omit blank lines and comments), and you can grab a copy of it from here. It uses SQLite for storage (which you should already have installed if you have Python installed), and it utilizes the great python-twitter library from Dewitt Clinton of Google. (Make sure you get the latest version for trunk; you’ll need simplejson as well, as python-twitter requires it.)

Just download the script and replace “username” and “password” at the top with your account credentials. (You can manage multiple accounts by adding another username/password pair to the ACCOUNTS variable.) Change the DB_PATH variable to point to the directory where you’ll keep your SQLite databases, and then add this to your crontab:

*/2 * * * * python /full/path/to/retweet.py

The script will run every other minute, republishing any tweets that start with “@username”, where “username” is the value you gave the USER variable. The only thing it stores in the SQLite database are the status id’s of the tweets it republishes, and it links each retweet to the original message being republished. If the new message is longer than 140 characters, it chops words off of the end, replacing them with “…” until it’s under the 140 character limit.

If you’re using this script to replace an existing retweet bot, you can supply it with the status id of the last message it re-published so that you don’t end up republishing a bunch of old tweets. To do that, just run it once like this:

$ python retweet.py 12345

where 12345 is the status id of the last message your existing bot published.

Feel free to download retweet.py and use it for your own purposes. All I ask is that if you make an improvement (or start up a new service with it), take a minute and mention it in the comments below.

Update: Some people have had to use the full path to Python (version 2.5 or greater) in their crontab to get retweet.py working properly.

Update: Retweet.py has been updated to ensure it keeps working as intended after Twitter started categorizing all tweets that contain a username as replies, not just ones that start with the username. Grab the updated version here.