Release Notes for MonitorURLs Channel Plug-in

Author

Allan B. Wilson; abwilson@awasu.com

Version/Date

Version 1.4.1; 02-Dec-05

License

No charge for personal or non-profit use. For commercial use, please e-mail the author.

Purpose

This plug-in monitors Web sites and notes if changes occur via RSS.

What has changed in this version?

This release fixes a typo that included “/?=” in links rather than just “?=”. Clicking on the these new links will open the corresponding URL in your browser like it is supposed to.

Earlier changes:

• It uses a library that allows it to fetch all monitored URLs in parallel. This means the plug-in runs to completion much more quickly, thus reducing or eliminating script time-out errors.

• Since its original release, Awasu has changed the way it recognizes new/unread items. To accommodate Awasu’s current approach, the plug-in now generates “unusual”, but valid and unique, links to ensure Awasu shows new content.

• The plug-in removes URLs that are no longer being monitored from its data file; this cleans things up a bit. Note, however, that if such an outdated URL has been cached by the async I/O library (referred to above), its corresponding cache file is not removed; if the size of the .cache directory becomes excessive because of “retired” URLs, you can simply delete the entire directory and all contents, since items will be recreated as necessary.

• It has been updated to use the latest py2exe (a package to convert a Python program to a .exe file). This reduces the number of files required as well as the total disk space needed.

Basic operation

This is a standard Awasu channel plug-in. Install it by clicking New Channel in the File menu, then selecting the plug-in, MonitorURLs.exe, to open it. Establish the URLs to monitor by going through the Awasu dialogs that appear.

If you need to monitor more URLs than the maximum handled by the plug-in (currently 10), you can create one or more additional channels. N.B. If you run more than one channel based on this plug-in, ensure the HistoryFile parameter is different for each such channel; this will avoid conflicts from the various copies overwriting each others’ files.

How does it work?

Specify one or more URLs to watch. Each time the channel is refreshed, the plug-in fetches the contents of and performs a checksum operation on each watched URL. (A checksum is just some arithmetic done on the characters that form a Web page.) If the checksum is different from the previous time, the page has changed; otherwise the page hasn’t changed. The news feed is updated to indicate whether each watched URL has changed or not.

The plug-in creates and maintains a .dat file in its directory to store the checksums and change-histories between invocations. It you delete or move this file, the plug-in will create a new one when it runs the next time, but any previous history information is lost (which probably won’t be a big deal). N.B. If you run more than one channel based on this plug-in, ensure the HistoryFile parameter is different for each such channel; this will avoid conflicts from the various copies overwriting each others’ files.

Operating environment

This plug-in is written in Python; the most recent development has been done with the 2.4.1 distribution, including winall, the win32 modules needed for full Windows support. It was “frozen” using py2exe 0.6.2.

Note that the plug-in uses a standard Python libarary module to retrieve the contents of Web pages being monitored. The library includes support for proxy server settings made via Internet Explorer. Therefore you shouldn’t experience any problems if you use a proxy server. (Note that you may be using a proxy server and not realize it: Someone else may have configured your system for you and specified a proxy server, or you may have set it up yourself long ago and simply forgotten. A quick check in Internet Explorer—Tools/Internet Options/Connections/LAN Settings—will reveal if this could be an issue for you or not.)