peteg's blog 2007-01-07-Blosxom.autumn

img update.

A massive port of some of my old PLog entries led me to update the img plugin. Now it does some fancier CSS stuff. Enjoy.

CSS brokenness: The CSS gunk from some W3 style examples which works fine... if you don't mind your images flush left or right. Why is there no simple way to centre arbitrary objects?

99writeback

I got a few doses of blog clap, and being bored and idle I put some effort into tidying up Blosxom's venerable writeback plugin and adding Captcha support. (I don't believe in the centralised blacklisting epitomised by akismet, it's too readily abused.) I get the impression that somebody in ee land is manually spamming, so I might need a plan B. My other concern is that the Captcha times out, meaning that if you take longer than a day to go from page load to post-comment it will bugger you up. Also the interaction with the back button is less than ideal.

99writeback (plugin)
writeback (flavour file for writebacks)
writebacksform (flavour file for the writeback form)

You'll need to instruct CPAN to install Authen::Captcha (or use your package manager to do it for you, or remove those bits of code). It should be easy to adapt it to use another Captcha library. I'm thinking about constructing a logic-puzzle one.

Part way through I realised just how fragile Blosxom is (no non-word characters in directory names? — and I was going to call this writeback++!) and how badly coded most plugins are (let's do everything ourselves! date functions, interpolation, file-backed databases, ...). If my perl was more fluent I'd have a shot at linting it all.

Hacking the RSS feed into shape.

Blosxom's stitch-the-template-and-content-together code is pretty nasty. Well, it's simple up to the point when one tries to use a fancy interpolation (substitution) engine to, say, implement a schmick img tag. RSS's not-invented-here-edness purportedly disallows HTML in the feed, but in practice it appears that's fine provided all the tags are suitably HTML armoured, which was the hoop that Blosxom was dutifully leaping through. I just tweaked the main script so that some interpolation occurs before the escaping, and the same again and some more after. Voila, with ugliness comes images. Yes, this sort of thing makes one yearn for a mainstream blogging engine.

While I'm ranting I've gotta say perl's approach of making everything magical wears thin fast. I want predictability, and while I accept that API docs are written to be read I don't appreciate having to read perlsyn and perlop (and perlre) manpages while doing simple imperative programming. How about: small language, verdant libraries instead of here's fifteen ways to write an enumerator? The great ideas in the language and fantastic libraries are heavily obfuscated by noise, and I don't believe it's possible to write robust perl applications — aspect-oriented programming has nothing on this for spaghetti. Any sane person looking at the perlsec manpage must surely agree with me — tainting supposedly works provided one doesn't defeat it, by omission or commission. Mutter, mutter.

Is it just my Safari that struggles with RSS feeds? Those bugs have been there for years now.

Blosxom plugin: img

(or: reinventing PLog, one piece at a time.)

I wanted to add images to the blog, and as I'm fed up with ImageMagick I was relieved to find that someone has written a more usable replacement for perl called Imager. You'll need to install that first, and it should be as easy as politely asking CPAN to do it for you. Also you'll need interpolate_fancy so you can invoke the method in your stories. Here's the code:

The instructions are in the script. It's still quite rough, and I'll be updating it as I go along. Take a good look at your error logs if things don't work.

The existing Blosxom image plugins are a lot fancier than this; I just wanted something that generates thumbnails and automatically adds the requisite attributes to the img tag. This photo is from my trip up to Berilee last month — if you squint you can see the car ferry at Berowra Waters. The markup is:


<@img.img src="IMG_1667.JPG"
 style="border-style: none; margin: 0 0 10px 10px; float: right; clear: right;" />

which, when run on my iBook, results in the XHTML:

<a href="http://localhost/~peteg/images/IMG_1667.JPG"><
 img src="http://localhost/~peteg/images/cache/tn_IMG_1667.JPG"
 width="93"
 height="70"
 style="border-style: none; margin: 0 0 10px 10px; float: right; clear: right;"
 alt="" /><
/a>

I get the impression that the interpolate_fancy plugin doesn't like having newlines in the arguments.

...and yes, I am vaguely aware that those suckling on the RSS nipple are not getting the full technicolour experience. Bear with me.