From: Ruby Quiz <james@...>
Date: 2007-07-05T21:51:11+09:00
Subject: [SUMMARY] LSRC Name Picker (#129)

Everyone who had my name in their example prize list deserves extra credit.  I
won millions in cash and prizes as I examined the solutions this week.  I can't
wait until the checks start coming in the mail.

I was occasionally beat out by some Yukihiro Matsumoto guy though.  Weird.

As usual, there were a lot of great solutions.  We had everything from clever
ASCII art to full GUI applications.  There were also a lot of clever ways to
taunt the attendees before a name is picked.

I'm going to look at Carl Porth's solution because the code is compact and
pretty approachable.  I also laughed out-loud when I ran his code.  Do play
around with the other solutions though or you will be missing a lot of fun
applications and code.

Carl's solution is a Camping application.  If you aren't too familiar with
Camping, as I wasn't, Carl's solution makes a nice gentle introduction.  Here's
how it begins:

	#!/usr/bin/env ruby -wKU
	
	require "rubygems"
	require "camping"
	require "RMagick"
	
	module Enumerable
	  def rand
	    entries[Kernel.rand(entries.size)]
	  end
	end
	
	Camping.goes :NamePicker
	
	# ...

First we see that Carl loads Camping and RMagick as his weapons of choice.  Then
we have a simple helper method for choosing a random member of some Enumerable
object.

The final line is how you always begin a Camping application.  It tells the
framework to create a namespace for your application in a module called
NamePicker.  The code then goes on to fill in that namespace:

	# ...
	
	module NamePicker::Controllers
	  class Index < R '/'
	    def get
	      render :index
	    end
	  end
	  
	  class Stylesheet < R '/style.css'
	    def get
	      @headers['Content-Type'] = 'text/css'
	      File.read(__FILE__).gsub(/.*__END__/m, '')
	    end
	  end
	  
	  class StaticImage < R '/images/(.*)'
	    def get(static_name)
	      @headers['Content-Type'] = "image/jpg"
	      @headers['X-Sendfile'] = "#{current_dir}/images/#{static_name}"
	    end
	  end
	  
	  class PickedNameImage < R '/picked_names/(.*?)\.gif'
	    def get(name)
	      make_image(name)
	      @headers['Content-Type'] = "image/gif"
	      @headers['X-Sendfile'] = "#{current_dir}/picked_names/#{name}.gif"
	    end
	  end
	  
	  class Page < R '/(\w+)'
	    def get(page_name)
	      render page_name
	    end
	  end
	end
	
	# ...

These are the controllers for this application.  They manage all of the traffic
through the pages.

The main point of interest in these is Camping's R() routing method.  As you can
see, it builds classes these controllers can inherit from.  The regular
expression you pass to it are the URLs that controller will service.

The first controller covers index requests.  The next two serve up static file
and image content.  PickedNameImage also serves images, but these are
dynamically generated from a selected name using the make_image() helper method.
Both types of images are handled by Camping just by the code setting some
headers about the file to send.  The final controller handles all other page
requests.

You can see that the Stylesheet controller makes use of some content embedded
later in the file.  It looks like this:

	# ...
	
	__END__
	
	body {
	  background-color:black;
	  text-align:center;
	  font-size:30px;              
	  font-family:impact;
	  color:red;
	  letter-spacing:3px;
	}
	a { color:red }
	p { margin:80px }

Now, unlike Rails, Camping views are just simple Ruby methods.  Here's a look at
those:

	# ...
	
	module NamePicker::Views
	  def layout
	    html do
	      head do
	        title "LOLPIXNAMES"
	        link :href=> R(Stylesheet), :rel=>'stylesheet', :type=>'text/css'
	      end      
	      body { self << yield }
	    end
	  end
	  
	  def index
	    p { img :src => R(StaticImage, "icanpixname.jpg") }
	    p { a "PIX A NAME", :href => '/pick_name' }
	  end
	  
	  def pick_name
	    all_names = open('names').readlines.map do |e|
	      e.gsub(/[^a-zA-Z 0-9]/,'')
	    end.reject { |e| e.empty? }
	    
	    picked_names = Dir["picked_names/*.gif"].map do |e|
	      e.sub(/picked_names\/(.*?)\.gif$/,'\\1')
	    end
	    
	    unpicked_names = all_names - picked_names
	    name = unpicked_names.rand
	    
	    p do
	      img :src => R(StaticImage, "ipixedname.jpg")
	      br
	      img :src => "picked_names/#{name}.gif"
	    end
	    p { a "I CAN PIX YR NAME AGAIN", :href => '/pick_name' }
	    p { a "KTHXBYE", :href => '/credits' }
	  end
	  
	  def credits
	    h1 "CREDITZ"
	    ul do
	      li "http://flickr.com/photos/mag3737/296800129/"
	      li "http://flickr.com/photos/brian-fitzgerald/608882248/"
	      li "http://www.ocf.berkeley.edu/~gordeon/fonts.html"
	    end
	    p "Carl Porth: badcarl@gmail.com"
	  end
	end
	
	# ...

The point of interest in these methods is the appearance of Markaby, which is
used to build HTML pages.  Markaby is very similar to Builder, if you are
familiar with that library, save that it doesn't need the explicit receiver.

The only action that does some work here is pick_name().  It pulls in names from
a name file, cross-checks those against what it has previously generated, and
selects an unpicked name.  Then it renders some HTML to show the selection.

All we have left at this point are the helper methods:

	# ...
	
	module NamePicker::Helpers
	  def make_image(text)
	    gif = Magick::ImageList.new
	    
	    decode_name(text.upcase).each do |frame_text|
	      frame = Magick::Image.new(30*frame_text.size, 52) do
	        self.background_color = 'black'
	      end
	
	      Magick::Draw.new.annotate(frame, 0,0,0,0, frame_text) do
	        self.font         = 'Impact.ttf'
	        self.pointsize    = 50
	        self.fill         = 'white'
	        self.stroke       = 'black'
	        self.stroke_width = 2
	        self.gravity      = Magick::CenterGravity
	      end
	
	      gif << frame
	    end
	    
	    gif.delay = 15
	    gif.iterations = 1
	    
	    gif.write("picked_names/#{text}.gif")
	  end
	  
	  def encode_name(name, indexes=[])
	    return [] if name.size == indexes.size + 1
	    
	    new_index = ((0...name.size).to_a - indexes).rand
	    random_words(name, indexes) + encode_name(name, indexes << new_index)
	  end
	  
	  def random_words(word, indexes_to_replace,
	                   number_of_words=indexes_to_replace.size)
	    (0..number_of_words).to_a.map do
	      new_word = word.dup
	      indexes_to_replace.each { |i| new_word[i] = ("A".."Z").rand }
	      new_word
	    end
	  end
	  
	  def decode_name(name)
	    encode_name(name).reverse
	  end
	  
	  def current_dir
	    File.expand_path(File.dirname(__FILE__))
	  end
	end

All of these methods work together to generate the selected name image shown
when the application runs.  The process builds an animated Gif image where the
frames show the name in various degrees of being scrambled.  As the animation
plays out, the name unscrambles to reveal a winner.

The make_image() method does the heavy lifting by iterating over variations of
the name and using RMagick to build frames for them.  The other methods scramble
the name by replacing certain indices with random letters.

That's about all there is to Carl's code, save some humor.  Fire it up in your
browser to make sure you get a taste of that.  "KTHXBYE!"

My thanks to all who solved the quiz, made me laugh, and, most importantly, to
those who awarded me prizes.

Tomorrow we have a problem using a c__ss_c g_me...