I’m pleased to bring the Python Module of the Week series to the O’Reilly ONLamp site. The main feed and home page are not moving, and all posts will continue to be posted here. Updated: The announcement post is here.

Back when Python 1.5.4 was hot and new, I wrote a class to serve as a basis for the many command line programs I was working on for myself and my employer. This was long before the Option Parsing Wars that resulted in the addition of optparse to the standard library. If optparse had been around, I probably wouldn’t have written CommandLineApp, but since all I had to work with at the time was getopt, and it operated at such a low level, I hacked together a helper class.

What’s new? I am happy with the API for feedcache, so I bumped the release to 1.0 and beta status. The package includes tests and 2 separate examples (one with shelve and another using threads and shove).

The getopt module is the old-school command line option parser which supports the conventions established by the Unix function getopt(). It parses an argument sequence, such as sys.argv and returns a sequence of (option, argument) pairs and a sequence of non-option arguments. Read more at pymotw.com: getopt

Jonathan LaCour presented an overview of SQLAlchemy at last night’s PyATL meeting, and now I have ORM envy. It’s too bad I can’t afford the effort that would be involved in replacing the in-house ORM we use at work, but I’ll definitely consider using it for my own projects.

Back in mid-June I promised Jeremy Jones that I would clean up some of the code I use for CastSampler.com to cache RSS and Atom feeds so he could look at it for his podgrabber project. I finally found some time to work on it this weekend (not quite 2 months later, sorry Jeremy). The result is feedcache, which I have released in “alpha” status, for now. I don’t usually bother releasing my code in alpha state, because that usually means I’m not actually using it anywhere with enough regularity to ensure that it is robust.

The shelve module can be used as a simple persistent storage option for Python objects when a relational database is overkill. The shelf is accessed by keys, just as with a dictionary. The values are pickled and written to a database created and managed by anydbm. Read more at pymotw.com: shelve

What’s new? There is a new release of AstronomyPictureOfTheDay available this morning. Version 2.0 is a substantial rewrite of the 1.1 version, but retains essentially the same functionality. The primary difference is that you no longer have to run a script to “personalize” it during installation. Now that it is distributed as an Application instead of an Automator workflow, you can just drag it to your Applications folder. The source is still created with Automator, but some of the Finder actions for working with directories have been replaced by Shell Script actions to perform the same operations.

Even though the glob API is very simple, the module packs a lot of power. It is useful in any situation where your program needs to look for a list of files on the filesystem with names matching a pattern. If you need a list of filenames that all have a certain extension, prefix, or any common string in the middle, use glob instead of writing code to scan the directory contents yourself.

The calendar module defines the Calendar class, which encapsulates calculations for values such as the dates of the weeks in a given month or year. In addition, the TextCalendar and HTMLCalendar classes can produce pre-formatted output. Read more at pymotw.com: calendar