So let’s say you have a custom primary key for a table - a hash_id. It’s only ever populated externally, not by your rails application, so you figure you don’t really need to specify the custom primary key in the model, since it’s only ever read-only.

class Subscriber < ActiveRecord::Base
  belongs_to :midget
  set_primary_key :hash_id
end

Well, think again.

First of all, you’ll still need it if you ever add any has_one or has_many associations with this model.

But even if you only have a belongs_to association, there’s an insidious bug that’s waiting to bite you in the ass. If you ever select the records from this table through an association :include

@circuses = Circus.find(:all, :include => {:midget => :unicycles })

rails will cache the unicycles in the resulting hash by primary key. And if you don’t tell it that they have a custom primary key, they will all be cached to a single record, with id of 0.

So, you’ll end up with the whole troupe having to ride the same unicycle. The insidiousness lies in the fact that if you select the association directly, it works as expected, because no caching is involved:

Midget.find_by_name('Alberto').unicycles

will get you the expected results, so you might not realize anything is wrong until much later.

The moral of the story is, if you change one of the assumptions rails relies on, make sure to explicitly specify the change, because you don’t know what else in rails relies on that assumption.

Pure CSS:

• Blueprint CSS
• 960.gs

More powerful:

• Compass - comes with support for Blueprint, and YUI css frameworks out of the box, written using Ruby SASS DSL.
  • compass-960 - compass support for 960
• Less - another DSL, also very very cool.
  • 960.less - 960.gs stylesheet rewritten in Less
  • 960 gist - 960.gs stylesheet rewritten and simplified in Less

HTML templating:

• ERB - old and busted
• HAML - pretty neat
• Erector - new hotness, indeed

excellent resource for ruby and rails projects and plugins

RubyAMP is a TextMate bundle that makes you more productive in editing, navigating, and debugging Ruby code. Now you can easily:

• auto-complete from all open tabs
• jump to a method, class, or fixture named under the cursor
• start the debugger on a series of RSpec examples and break at the current line
• inspect by highlighting to evaluate to tooltip or clipboard
• fire up a Merb/Rails server or console for your current app
• tail development.log

$_ expands to last argument in previous command.

ie

cp a.txt /some/long/path/and/some_other_name.txt
vim $_

will open the just-moved file without retyping the whole damn thing. so useful.

Just so I don’t forget if I need this later… nice in-field labels for forms.

Exceptional and Hoptoad two exception monitoring services.

I’ve been using Rick Olson’s exception_logger plugin, quite useful and has the advantage of being self-hosted.

My first github release. Woo.

Hacking away on a new flash project, these links came in handy:

Dynamic xml-based flash gallery tutorial

Dynamic xml-based streaming audio playback

Basic pausing/resuming sound playback

Pausing/resuming sound playback with fadeout/fadein

For any perl geeks out there: a free pdf of Higher Order Perl is available here: http://bit.ly/HOperl