Apr 01 2006

The Rails aren’t so smooth if you want some [Image]Magic[k]

Published by at 4:52 pm under Technology   

We started some work recently with the much-hyped Ruby / Rails combination. For the most part, it’s lived up to the hype; going down it’s ‘happy path’ has been far more productive than work with some other web app frameworks and languages. But today I hit several sources of Ruby / Rails pain in a row, and it seems worth writing about them, perhaps to save the next fellow from the same.

The nexus of the pain is RMagick, which, once working, is a great set of tools for drawing graphics in Ruby. My partner on this project had some trouble getting the numerous dependencies in place on Linux and/or MacOS; he thought it would go much easier on Windows, since there are far fewer dependencies.

Indeed, it should have been easy. I went over to the RMagick download site and grabbed the latest and greatest almost-ready Windows Gem, version 1.10.1. Its instructions said I needed Ruby 1.8.4, so I remove my old 1.8.2 and grabbed Curt‘s One-click ruby installer. It is a release candidate (“184-16 release candidate 1”), but Curt said the other night that the installed software is ready to go, he’s only working out a few installer issues.

All good… except now nothing worked at all. Lots of errors like “./script/../config/../app/views/admin/signin_form.rhtml:3: Invalid char `\360′ in expression” and “./script/../config/../app/views/layouts/login.rhtml:2: parse error, unexpected $, expecting kEND”. After considerable searchings I found clues and then the answer. The RMagic docs led me astray – by ignoring them and going back to 1.8.2, it all works again… for small values of “all”… because 1.8.2 doesn’t include Rake, Rails 1.1 prefers 1.8.4, etc.  It appears, if I understand the various posts correctly, that RMagick breaks Ruby by changing a method on String. This is a rather unfortunate, surprising, and in my judgement, bad thing for such a library to do; I can’t imagine offhand why RMagick should do anything at all until invoked. At minimum I’d hope to be able to trust an image manipulation library to not touch, much less break, the String class 🙂

That’s enough digging for now; hopefully when I return to this, the issues will be worked out, there will be matching, current, compatible versions of all these parts, and things will run smoothly along the “rails” as usual.

If you found this post useful, please link to it from your web site, mention it online, or mention it to a colleague.

No responses yet

Comments are closed.