Solace is a web app I created to search multiple Craigslist locations for the same query. It uses YQL to make the search, but in order to generate the YQL queries I first needed to generate a list of all valid Craigslist locations.
Update: Full source code for Solace is now available on GitHub.
There were a fair number of locations in the US, so I wrote a Ruby class that uses Nokogiri to scrape the locations directly from Craigslist’s web site.
The extraction process grabs all of the links from the supplied Craigslist URL and parses out the subdomain and link text. Then I preload the JavaScript portion of the app by dumping the JSON into an ERB template.
I still plan on writing up a description of the JavaScript portion of the app (which is now, as of 2011, written in CoffeeScript). In the meantime, check out GitHub for the source.