Urban Puddle

By this stage it should have been easy for me to get an observe field working in Rails but for some reason I just couldn't pull it off. I googled a bunch and still couldn't get an answer I was looking for (that worked). If you're in the same boat, here's a tiny snippet of code that will let you show and hide a div with radio buttons. Handy if you want to show different forms depending on the selection.

If you're into testing your websites on lots of different browsers then you probably have a solution for IE6, IE7, Safari, Konqueror and Firefox. If you're using the AMD64 version of Debian or Ubuntu you may also want to add Opera to the mix. Unfortunately, if you go through their website you'll only be offered the i386 build. So what do you do if you want the Opera browser natively on your x86_64 machine?

A while back I had a tip about getting a user's IP address using Ruby. I'm not exactly sure when it happened but the method I used in that post suddenly stopped working on me. If you used that to get a user's IP address in your code you may find that all values are coming back as 127.0.0.1. Hardly useful. Instead, try this snippet:

<% @ip = request.remote_ip  %>

I was pretty stunned today when I signed up for Online Banking at SunTrust to find out that their corporate version for small business wouldn't work with Firefox. This has been the case since at least 2005 when I last interacted with them so it's not a new problem. Message to SunTrust: There are more banks than web browsers. I am not changing to Windows and using IE just because you can't get your act together.

If you upgraded from Tiger to Apple's OS X 10.5 Leopard you may find a few things that were OS related stopped working. In my case, PHP5 no longer responded as expected. Sure enough, some digging found it was disabled. Fortunately, it's pretty simple to get running again in Leopard.

Open up a terminal and type:

sudo vi /etc/apache2/httpd.conf +114

After typing in your password you'll find yourself on the exact line related to PHP5 that you need to uncomment. Remove the # at the start of the line so it looks like this:

LoadModule php5_module        libexec/apache2/libphp5.so

Then head over to your System preferences and stop/start your web server in the Sharing pane by unchecking and re-checking the box that says Web Sharing. That'll restart Apache2 for you -- this time with PHP5 enabled.

When you write code, the text-editor you use makes a big difference in your productivity. Textmate is the biggest thing I miss from using Mac OSX. There have been many attempts and some progress has been made along the way. I went through a few different applications but I think I've finally settled on Gedit. If you're interested in reading why (and where I went to customize my install) then by all means click through.

I wrote up an article on compiling ImageMagick and installing Rmagick 2.1 but for some reason, even though the gem got installed, I couldn't resize images. After a half day banging my head against it, I finally gave up. Next up, ImageScience. It uses less memory anyway so if this serves your purpose, follow along.

If you've updated your gems recently you may have noticed that the latest rmagick isn't working. I've run into this problem on Feisty, Gutsy, and Debian Sid. The culprit is a version of Imagemagick older than 6.3.0. The Rmagick gem used to work with Graphicmagick so I'm not entirely sure why it refuses to install, but I get an error that says:

Can't install RMagick 2.0.0. You must have ImageMagick 6.3.0 or later.

*** extconf.rb failed ***

Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/rmagick-2.1.0 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/rmagick-2.1.0/ext/RMagick/gem_make.out

Bleh. In order to get around this, you'll have to compile Imagemagick from source. Here's how I did it (the somewhat painless way)

If you're accepting credit cards in your ruby application you may need to use the Mod10 (also known as a Luhn) algorithm to check the final digit. There's sample code to do that in just about every language including ruby. I'll post my snippet below plus reverse it so you can create a check digit too. Why? Because sometimes you need to do that and also because it never hurts to independently verify your check digit with another method. Here goes:

Following up a bit on a post I wrote a few days ago on some tips to upgrading your rails app for Rails 2. What happens if it just won't work? Then, later on you do a fresh install of rails and get the latest/greatest version while your app still depends on an older version? Well, if you didn't freeze rails with your app you still have a way out: install an older version of rails with rubygems. The command is easy:

sudo gem install rails --version 1.2.6

Lastly, you'll want to make sure your config/environment.rb has a line in it to match your older version of rails:

RAILS_GEM_VERSION = '1.2.6'