Simple object regex method router

gistfile1.ru

# >> class MyClass; include RegexRouter; end
# => MyClass
# >> obj = MyClass.new
# => #<MyClass:0x101859100 @routes={}>
# >> obj[%r(/words/(\w+))] = lambda do |word| puts "Found: #{word}" end
# => #<Proc:0x000000010184bb40@(irb):3>
# >> obj.go '/words/boo'
# Found: boo
# => nil

module RegexRouter
  def self.included(base)
    base.class_eval do
      def initialize(*args, &block)
        @routes = {}
        super(*args, &block)
      end
    end
  end
    
  def []=(*args)
    @routes.send :[]=, *(args.map { |arg| arg.is_a?(String) ? Regexp.new(arg) : arg })
  end
  
  def go(route)
    @routes.each do |regex, block|
      if match = regex.match(route)
        return (match.captures.any? ? block.call(*match.captures) : block.call)
      end
    end
    raise NoMethodError, "Route not found: #{route}"
  end
  
  def routes
    @routes
  end
  
  def @routes.count
    @routes.keys.length
  end
end

if $0 =~ /spec/
  require 'rubygems'
  gem 'rspec', '>= 1.3.0'; require 'spec'

  describe RegexRouter do
    before do
      class MyClass 
        include RegexRouter 
      end
      @instance = MyClass.new
    end
  
    context 'methods' do
      subject { @instance }
      it { should respond_to :[]= }
      it { should respond_to :routes }      
      it { subject.routes.should respond_to(:count) }
    end

    it 'works by passing a regex to [] and a block increments the route count by 1' do
      @instance[/boo/] = lambda do 'omg' end
      @instance.routes.count.should == 1
    end
  
    context 'dispatching routes' do
      it 'dispatches a method associated with a route when the param matches' do
        jug = 'empty'
        @instance[/foo/] = lambda do jug = 'water' end
        @instance.go 'foo'
        jug.should == 'water'
      end

      it "uses regex captures as arguments for a route's block" do
        book = nil
        @instance[%r(/books/(\d))] = lambda do |book_id|
          book = book_id
        end
        @instance.go '/books/1'
        book.should == '1'
      end
    end

    it 'raises a NoMethodError when dispatching to a non-existent route' do
      lambda do
        @instance.go 'zomg'
      end.should raise_error(NoMethodError)
    end
  end
end