Question

I want figure out the connection between the Rack and Sinatra, so I dig into the source code, then I found the the definition of the basic class method get:

def get(path, opts={}, &block)
  conditions = @conditions.dup
  route('GET', path, opts, &block)

  @conditions = conditions
  route('HEAD', path, opts, &block)
end

now what’s the method: route? I’m currently using yard document tool, I just can’t find the definition of route in any Sinatra code or even Rack code.

Answer 1

You didn’t look for the source code very well 🙂 10 lines below #get method definition there is a definition of route private method:

# lib/sinatra/base.rb, line 1212
private
      def route(verb, path, options={}, &block)
        # Because of self.options.host
        host_name(options.delete(:host)) if options.key?(:host)
        enable :empty_path_info if path == "" and empty_path_info.nil?
        signature = compile!(verb, path, block, options)
        (@routes[verb] ||= []) << signature
        invoke_hook(:route_added, verb, path, block)
        signature
      end

This is a private method and you will not find it in the Sinatra documentation.

Generally this method does the following: It create proc from passed &block, combine it with http path, keys and invocation conditions (inside compile! method) and store it in @routes[verb] class instance variable so that block may be found by path and conditions and executed later on (this class also has attr_reader :routes defined so that other classes may get acces to its @routes instance variable).

Later when you get http request matching this route (@request instance variable of Base class ) the block is executed inside Base#route! method (see line 795).

I would recommend you to use some IDE that help to examin source code. For example I use Rubymine for this purpose and its feature Go To -> Declaration: Just put your cursor on the variable/method/class/etc, press F12 and Rubymine will find it for you, even in source code of connected gems.