Blosxom Plug-in: multicat
I love my blogging software - blosxom. It's just so light, compact, and easy to use. Blosxom is especially nice for someone like myself that prefers to use a mouse as little as possible while using a computer. I can use the command line to author a new blog entry using vi, spell check the new entry using aspell, modify the blog entry's publication date using touch, and use the standard unix file system commands to insert my new blog entry into my blog file structure (i.e. my blog's category heirarchy). And I can do all this as fast as I can type the commands at the shell prompt.

There is one limitation of blosxom that I just recently bumped up against. The limitation is a byproduct of using the blosxom data directory structure to double as the blog's category heirarchy. Each blog entry lives in one directory, and thus one category. Sure, a blog entry can be copied into (or a link made in) another directory to associate the entry with a secondary category, but then blosxom will show that entry multiple times. So, that's no good.

I wanted to find a way around this behavior primarily because I wished to associate the daily journal entries (located in "/daily_journal/2006") that I composed about our recent trip to Vancouver with a new category (something like "/vacations/2006/vancouver"). That way, I could still read my daily journal in a linear fashion using a URL like:

http://rus.berrett.org/blog/daily_journal/2006/

yet, at the same time, access just the journal entries that detail our Vancouver vacation using a URL like:

http://rus.berrett.org/blog/vacations/2006/vancouver/

(Note: the above examples of URLs to access blosxom blog entries presume that my modifications to blosxom with regard to "viewing by date" have been applied to the blosxom installation).

With that goal in mind (one entry - many categories), I set to the task of creating a blosxom plug-in that will allow me to "file" a blosxom entry under one or more different categories while, at the same time, suppress the display of the multiples. I was able to create a plug-in (which I've named "multicat") that does exactly that.

The "multicat" plug-in allows me to easily classify a single entry under many different categories (i.e. different directories) using symbolic links. The multicat plug-in controls when the symlinks to the entries are displayed and when they are hidden. Thus, the display of duplicate entries (which is the normal blosxom behavior when symlinks to files are encountered) is suppressed. Support for the comments plug-in and the writeback plug-in is built-in. Comments (or writebacks) that are added to or appear on a source entry will show up in the symlinked entry and vice versa.

I think what I have done is very clever and I'm very pleased with the result. I can now create symlinks to blog entries in other secondary categories and, in effect, file a single blog entry under multiple categories. This was something that was impossible to do before (and I scoured over many different other blosxom plug-ins) and, ultimately, I think it could be very useful to the blosxom blogging community at-large (but I could be wrong about that).

So, using the example above, I can now build a URL to access all of the entries in my daily journal that are just about our recent trip to Vancouver. Check it out:

http://rus.berrett.org/blog/vacations/2006/vancouver/

Note that each of those entries has not one, but two, categories that it is associated with. Mission accomplished.

More information about the multicat plug-in can be gleaned by reviewing the source code (my perl reads pretty easy), or by reading the man page. I have provided links to both (as well as my development log) below:

multicat source code
multicat(1) man page
multicat development log

cheers!

(Update Mon Mar 13 00:47:59 PST 2006 // fixed a grammatical error)