I’m working interactively in irb, and I tweak the class to make changes. The changes won’t be reflected in the irb session unless you reload the class.


irb >> load 'document.rb'


Make sure to add the file extension. Unlike require, load needs the full filename.

Jeff Atwood and team have built a new product called Stack Overflow, a question and answer site for programmers. It’s very early, but I think it will be successful. It’s certainly been useful for me.

For Serendeputy, I’m building an index of articles relevant to me, and I need to be able to generate a unique id based on the url. I experimented with (what appeared to be) the obvious solution, but it wasn’t working. So, I asked the question: “What’s the best way to hash a url in Ruby?” Within three minutes, I got a useful answer. By morning, I received three answers, with the best answer sorted to the top.

This is incredibly useful. I have a stack of Ruby books at my desk, and I’m often flipping through them trying to find a specific answer. I generally know *what* I’m trying to accomplish; I’m just lost on the syntax and the proper Ruby idiom to use. If my experience is typical, then Stack Overflow is a very useful supplement to these references.

Stack Overflow has a ton of Google juice already. My question is number one for the relevant search query: hash a url ruby. Most of the time when I do a Google search for specific questions, I get links to the Ruby documentation (which I already have) and a decent amount of off-topic spam. If Stack Overflow gets a critical mass of specific questions with canonical answers, then Google will become much more useful for everyone.

I’m very impressed with how they’ve focused on the customer experience. I’m trying to keep the same ideals with my project. Unlike those folks at that annoying site, they have everything open and clean. They have advertising, but it’s inobtrusive. And, the value of the product was so high that I actually made a point of looking at the advertising, seeing that an advertiser who’s associating with this useful an application is probably worth checking out. It’s amazing what optimizing for the customer experience will do for you.

It reminds me of how I felt in 1999 when I switched from Alta Vista to Google.

One quibble: Requiring people to get an OpenId is a mistake. Everyone in their target market has a simple throwaway handle/password combination that they use on all these sites. Unless it’s a pragmatic choice — they don’t have to program the authentication module — I think it’s a mistake to go against the grain of what people expect for these sites. Requiring an OpenId dissuaded me from registering; I just posted as a guest.

There’s undoubtedly a smarter way to do this, but I couldn’t figure it out. I’m doing a functional (controller) test for one of my rails pages. I want to make sure that the picture coming back is exactly 224 pixels high.

I couldn’t find a way to do this using the assert_select syntax, but this workaround seems to work:


  def test_picture_height
    assert_select "div.secondary div.lead_picture img[height]" do |height|
      # pull the tag -- this gives you the whole img tag
      @h = height.to_s
      # extract the height
      @h.gsub!(/.*height="(.*?)".*$/, '\1')
      #run the test
      assert_equal @h, "224"
    end
  end


This can be tightened up, but I left it explicit so that I could understand what I was going. The assert select makes sure that I’m setting the height. The block makes sure that it’s equal to 224.

Are there easier ways to do this?