Accessing the irb in a modular Sinatra application - ruby

Question

I am building an application which subclasses Sinatra like so:
require 'rubygems'
require 'sinatra/base'
require 'sinatra/assetpack'
class App < Sinatra::Base
...
run!
end
How can I access irb? Options are not parsed when executing sinatra this way, how do I programmatically open an irb shell?

Answer 1

Just type as below (at the shell prompt):
irb -r ./my_app.rb

Answer 2

I'm a little confused whether you want to open an IRB session from within your app (?) or use IRB to debug your Sinatra project?
For debugging Rack-based apps (such as Sinatra), I like using the racksh gem, which "is like script/console in Rails" for Rack applications. Its main advantage over IRB is that racksh loads the entire application environment into the shell, making debugging a breeze.
From racksh's Github page: "It's purpose is to allow developer to introspect his application and/or make some initial setup. You can for example run DataMapper.auto_migrate! or make a request to /users/666 and check response details. It's mainly aimed at apps that don't have console-like component (ie. apps built with Sinatra) but all frameworks can benefit from interactive Rack stack and request introspection."
However, racksh requires your app to have a config.ru file, so you would have to re-write your app:
# in config.ru
require 'rubygems'
require 'sinatra/base'
require 'sinatra/assetpack'
require 'app.rb'
# in app.rb
class App < Sinatra::Base
...
run!
end
Then in your app folder (where config.ru resides):
$ gem install racksh # or add gem 'racksh' to your Gemfile and run bundle
$ racksh

Answer 3

Check this simple search interface for Microsoft's Bing using Sinatra and binger gem.
If you follow the instructions from there you will understand better.
First at all, create a Gemfile and add:
source "https://rubygems.org"
gem 'sinatra'
gem 'binger'
Then run the bundle command that will generated Gemfile.lock.
Then create a config.ru file, and add by example:
require 'rubygems'
require 'bundler'
Bundler.require
require './app.rb'
run MyApp
Your app.rb could look like this:
class MyApp < Sinatra::Base
get '/' do
#title = "Index"
erb:index
end
end
You must have a folder named views. Create index.erb and add:
< % = #title % >
Finally, run rackup.
Source: https://github.com/thinkphp/sinatra-bing
Demo: http://sinatra-bing.herokuapp.com/