RegExp and Konfabulator's one-liner widget
I've recently been trying out one-liner, a handy Konfabulator widget. This is a highly customizable widget that uses regular expressions to extract data from a user-specified webpage and display it on screen with regular updates. The suggested uses are to keep track of new comments on a site such as VersionTracker, or to keep track of the latest version of an application. This latter use is what I like it for.
Some history: a few years back, VersionTracker made their name by offering a free service to check for updates of all your installed software. It was a bit slow (at the time everyone had dial-up connections) but it worked very well and was a big timesaver. Rather than Get-Info on each application (or worse yet, launch it just to check the version number), you could just run VersionTracker's app and it would tell you which of your installed apps had an update available online. Unfortunately, VersionTracker now want us to pay for this program (now called VersionTracker Pro, obviously). Worse yet, it's not even a traditional "pay-once" program. We now have to pay US$50 every year to use the service! This is known in some industries as a "bait and switch" scam ;-) but in the computer world it is unhappily quite common (mac.com anyone?)
Back to one-liner. What I wanted to do with it was to set it up to check for updates to a few apps that I regularly use (and have some minor issue that I'm waiting for a bug-fix for). After a bit of reading, including this nicely done RegExp tutorial, I was able to put together some generic expressions to parse VersionTracker entries for the information I want (i.e. the latest version number). Simply create a new entry in one-liner and enter the following values (use the VersionTracker URL of the application you want to watch):
Update: I realised VersionTracker have a different page for each version, which makes tracking the newest version difficult. MacUpdate only keeps the latest version which simplifies things a lot.
Parse Target URL (use the MacUpdate URL of the app you want to track):
http://www.macupdate.com/info.php/id/13341
RegExp1(A):
/<title>(.*)<\/title>/[1]
Title:
/<title>(.*)<\/title>/[1]
Display:
A
This will make one-liner request the MacUpdate page and display what the current version number of the software is. You can set the interval in the one-liner preferences. This is the result (the bottom five lines are the result of this technique):
A good place to ask RegExp-related questions is regexp.org.
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