Use Ruby 1.9 Named Captures To Implement A Router

router.rb

class Router
  attr_accessor :routes

  WILDCARD_PATTERN = /\/\*/
  NAMED_SEGMENTS_PATTERN = /\/:([^$\/]+)/
  NAMED_SEGMENTS_REPLACEMENT_PATTERN = /\/:([^$\/]+)/

  def initialize(routes)
    @routes = routes
  end

  def route(path)
    routes.each do |route|
      if route.first =~ WILDCARD_PATTERN
        src = "\\A#{route.first.gsub('*','(.*)')}\\Z"
        if match = path.match(Regexp.new(src))
          return [route.last, match[1].split('/')]
        end
      elsif route.first =~ NAMED_SEGMENTS_PATTERN
        src = "\\A#{route.first.gsub(NAMED_SEGMENTS_REPLACEMENT_PATTERN, '/(?<\1>[^$/]+)')}\\Z"
        if match = path.match(Regexp.new(src))
          return [route.last, Hash[match.names.zip(match.captures)]]
        end
      elsif path == route.first
        return [route.last]
      end
    end
    nil
  end
end

router_spec.rb

require 'router'

describe Router do
  it "should match using a literal string if route does not contain a '*'" do
    router = Router.new([["/foo", 1], ["/bar", 2], ["/bark", 3]])
    router.route("/foo").should == [1]
    router.route("/bar").should == [2]
    router.route("/bark").should == [3]
    router.route("/fail").should be_nil
  end

  it "should match using a Regexp if the route contains a '*'" do
    router = Router.new([["/foo", 1], ["/bar/*", 2], ["/bark", 3]])
    router.route("/foo").should == [1]
    router.route("/bar/").should == [2, []]
    router.route("/bar").should be_nil
    router.route("/bar/bang").should == [2, ["bang"]]
    router.route("/bark").should == [3]
    router.route("/fail").should be_nil
  end

  it "should match using a Regexp if the route contains named segments" do
    router = Router.new([["/foo", 1], ["/foo/:name", 2], ["/foo/:name/:action", 3]])
    router.route("/foo").should == [1]
    router.route("/foo/bar").should == [2, { "name" => "bar" }]
    router.route("/foo/bar/bang").should == [3, { "name" => "bar", "action" => "bang" }]
  end

end