Composite Primary Keys (CPK) and RSpec Fixtures

I was banging my head against the proverbial wall all week.  This morning's travail was an error like this in my specs:

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.first
/path/to/rails/app/vendor/gems/composite_primary_keys-1.0.5/lib/composite_primary_keys/base.rb:239:in `find_from_ids'

...After some digging, I found a page that explained the problem, and revealed that you need this in your spec/spec_helper.rb file:

load 'composite_primary_keys/fixtures.rb'

I feel much better now.

Repetitive Stress

So, I've been programming pretty much non-stop for the past few months.  My wrists ad neck were suffering.

Rather than start wearing braces again, I opted to try this program (Mac-only) that interrupts you every so often.  ...I have it set for 12 seconds every few minutes, and 10 minutes every hour.  I started using it about a month aogo

It seems to have done wonders for my hands and wrists, so I highly recommend it.

Ain't done squat for my neck, though.  ...And some days, it gets really bad. : \

Open Source, Sickles, and Hammers

(Image cc-by jagelado)

Using Vim and MySQL to Create Fixtures (for Rails)

...I've had to build a lot of fixtures using extant data from a MySQL database.  I don't want the whole database in my fixtures... just a subset, based on some examples I use in my specs.

So I run a query to get the subset I want, being sure to grab all the contents from a given table (and ONLY one table).  Something like this:

SELECT st.*
  FROM a_fancy_table ft
    JOIN some_table st ON (ft.id = st.a_fancy_table_id)
  WHERE ft.id IN (1, 2, 3)\G

The \G is essential, here.  I then copy the output of that to the some_table.yml file, created with vim.

Then:

1. <ap multiple times, until everything is left-justified, then
2. >ap once, so that it's all indented 1 level, then
   
3. :%s/  \*\+ \(\d\+\). row \*\+/^Msome_prefix_\1:
4. finally, rename any of those that are really significant.

...Of course, the ^M is really ^v[ENTER], and the some_prefix is whatever you want to name your objects.

...If that makes sense, you'll find it's a huge time-saver.  Unless you're copying entire tables, in which case you can use Dmitry's script.

ZenTest and autotest in Windows with RSpec and Rails

I've been trying to monkey-patch ZenTest's autotest for over a month now.  Originally, I was trying to get it to work (well) with snarl, but that just seems frivolous at this point.  My focus now is just to get the damn tests working as they should.

First of all, Windows doesn't let you break out of the loop.  ...At least, not that I've ever seen.  I haven't heard a SINGLE person on the web talk about this, which is frustrating.  Maybe I'm missing something stupid, but I know other people that this is happening to.

Anyway, the fix for that is to change the "Kernel.sleep 1.5" on line 291 of autotest.rb... it works if you change it to this:

    30.times { Kernel.sleep 0.05 }

I don't know why, but I'm assuming it has something to do with how sleep is implemented on Windows that causes it to lose the scope of self.interrupted.  Or something.  Whatever: this works.

Next, I'll try to find a regex that will actaully find the right files to run, when there has been a change!  Grr.

Optics

So, I was just thinking about microscopic images, and how they're always so much blurrier than illustrations.  I was thinking about how, in videos, you can see various parts of the organism sharply, depending on the focus of the optics... it's just a razor-thin depth of field.

Then I thought: hey, wait, we have HDR photography.  ...Why can't we use this at a microscopic level to increase clarity?

I could even imagine a machine-controlled microscope that produces one image from a composite of multiple images shot at different focal lengths, helping to bring the entire image into maximal focus.

...Of course, I'm sure someone else has already thought of this.

Posting Ruby

So, I broke down and did some research on how to post code to blogger so that it doesn't look hideous. It wasn't nearly as simple as I wanted it to be (most notably, it was a serious pain to use cocoa to use the pasteboard for converting text)... so I hacked together a little rails project that handles things for me using web forms. It would be a long post to explain all the details, but I'll cover the basics.

First, sudo gem install syntax. Then create a new rails project and get it up and running. When you've got that, generate a controller called "Convert". The code for the controller should look like this:

class ConvertController < ApplicationController
  def ruby
    render :action => :ruby
  end
  def to_html
    require 'syntax/convertors/html'
    convertor = Syntax::Convertors::HTML.for_syntax params[:type]
    @code = convertor.convert(params[:text]).gsub(/<span class="punct">([^<]*)<([^<]*)</, "<span class=\"punct\">\\1&lt\\2<")
    render :action => :to_html
  end
end

And then you'll need a view for 'ruby.html.erb'.:

<h1>Convert What?</h1>
<p>
 <% form_tag('/convert/to_html') do %>
 <table><tr><td><%= text_area_tag 'text', '', {:cols => 80, :rows => 30} %></td>
   <td><%= radio_button_tag 'type', 'ruby', true%>Ruby<br/>
    <%= radio_button_tag 'type', 'xml'%>HTML/XML<br/>
    <%= submit_tag 'convert to HTML' ><td>tr><table>
 <% end %>
</p>

...And a basic response form in 'to_html.html.erb':

<h1>The raw HTML:</h1>
<pre><%= text_area_tag('whatever', @code, {:cols => 80, :rows => 30}) %></pre>
<h1>The results:</h1>
<%= @code.gsub(/&amp;/, '&') %>

...You'll also want to set up the CSS for your site, using the CSS from the site where I stole this idea from. Polishing things is an exercise left to the reader... but that should get you started.