How to start a Sinatra app using "run"

Question

I tried to use a Gemfile in my Sinatra app, but when I launched my app I got this error:

$ ruby config.ru  
config.ru:7:in `<main>': undefined method `run' for main:Object (NoMethodError)

Here are my three files:

hi.rb:

get "/" do
  "Hello world"
end

Gemfile:

gem "sinatra"

config.ru:

require 'rubygems'
require 'bundler'

Bundler.require

require File.join(File.dirname(__FILE__), 'hi.rb')
run Sinatra::Application

What did I do wrong? How can I fix this?

Use `rackup` command to start your app. Or install shotgun gem, that is more convenient for development. — taro, Sep 17 '12 at 10:13

score 39 · Accepted Answer · answered Sep 17 '12 at 10:15

39

You should launch the application with:

rackup config.ru

answered Sep 17 '12 at 10:15

Riccardo Marotti

3

Can you explain why rackup is necessary or shotgun is necessary? – gustavoanalytics Mar 08 '17 at 21:29
2

@gustavoanalytics rackup is the script which runs the first and only executable inside a gem called rack using ruby. That executable is also called rackup. Inside it sets up environment for rack applications and starts your default server. – nurettin Jul 29 '18 at 21:33

1 Answers1