# Simplest example:<\/span>\n#<\/span>\n#   use Rack::Get, '/ping_monitor' do<\/span>\n#     'pong'<\/span>\n#   end<\/span>\n#<\/span>\n# Rack::Response object is yielded as second argument to block:<\/span>\n#<\/span>\n#   use Rack::Get, '/json' do |env, response|<\/span>\n#     response['Content-Type'] = 'application/json'<\/span>\n#     %({"foo": "bar"})<\/span>\n#   end<\/span>\n#<\/span>\n# Example with regular expression -- match data object is yielded as third argument to block<\/span>\n# <\/span>\n#   use Rack::Get, %r{^/(john|paul|george|ringo)} do |env, response, match|<\/span>\n#     "Hello, #{match[1]}"<\/span>\n#   end<\/span>\n#<\/span>\n# A false/nil return from block will not return a response; control will continue down the<\/span>\n# Rack stack:<\/span>\n#<\/span>\n#   use Rack::Get, '/api_key' do |env|<\/span>\n#     '12345' if env['myapp.user'].authorized?<\/span>\n#   end<\/span>\nmodule<\/span> Rack<\/span>\n  class<\/span> Get<\/span>\n    def<\/span> initialize<\/span>(<\/span>app<\/span>,<\/span> path<\/span>,<\/span> &<\/span>block<\/span>)<\/span>\n      @app<\/span> =<\/span> app<\/span>\n      @path<\/span> =<\/span> path<\/span>\n      @block<\/span> =<\/span> block<\/span>\n    end<\/span>\n\n    def<\/span> call<\/span>(<\/span>env<\/span>)<\/span>\n      path<\/span> =<\/span> env<\/span>[<\/span>'PATH_INFO'<\/span>].<\/span>to_s<\/span>\n      if<\/span> env<\/span>[<\/span>'REQUEST_METHOD'<\/span>]<\/span> ==<\/span> 'GET'<\/span> &&<\/span> ((<\/span>@path<\/span>.<\/span>is_a?<\/span>(<\/span>Regexp<\/span>)<\/span> &&<\/span> match<\/span> =<\/span> @path<\/span>.<\/span>match<\/span>(<\/span>path<\/span>))<\/span> ||<\/span> @path<\/span> ==<\/span> path<\/span>)<\/span>\n        response<\/span> =<\/span> Rack<\/span>::<\/span>Response<\/span>.<\/span>new<\/span>\n        response<\/span>.<\/span>body<\/span> =<\/span> @block<\/span>.<\/span>call<\/span>(<\/span>env<\/span>,<\/span> response<\/span>,<\/span> match<\/span>)<\/span>\n        response<\/span>.<\/span>body<\/span> ?<\/span> response<\/span>.<\/span>finish<\/span> :<\/span> @app<\/span>.<\/span>call<\/span>(<\/span>env<\/span>)<\/span>\n      else<\/span>\n        @app<\/span>.<\/span>call<\/span>(<\/span>env<\/span>)<\/span>\n      end<\/span>\n    end<\/span>\n  end<\/span>\nend<\/span>\n<\/pre><\/div>\n