Sinatra: Classy web-development dressed in a DSL

Written on November 17, 2007 by ceefour

Sinatra is a new cool open-source DSL-driven web application framework!

This super-sexy DSL runs at lighting speed. It sits on top of Mongrel and was written to be thread-safe, sleek and tiny. And an entire web-application can be written and contained in one file (or a small collection of files)!

It’s super easy to use! Let’s create an app from scratch to demonstrate!

Install!

gem install sinatra -y

Use!

• Create a file called lyrics.rb (or any name you like)
• Add

    require 'rubygems'
  
    require 'sinatra'

• Run (yes, with just ruby)

    % ruby lyrics.rb
  
    == Sinata has taken the stage on port 4567!

• Take a moment and view the default page localhost:4567. Go ahead and bask in it‘s glory.
• Notice:
  • It didn‘t create any page to show you that default page (just a cool thing to see, that‘s all)
  • There was nothing generated other than a log file
  • Sinatra is a really cool name for a web-framework that‘s a DSL
• Modify lyrics.rb by adding:

    get '/' do
  
      'Hello World'
  
    end

• Refresh (no need to restart Sinatra):

    http://localhost:4567

• Modify again (then refresh):

•   get '/' do
  
      <<-HTML
  
        <form action='/' method="POST">
  
          <input type="text" name="name" />
  
          <input type="submit" value="Say my name!" />
  
        </form>
  
      HTML
  
    end  post '/' do
  
      "Hello #{params[:name] || 'World'}!"
  
    end

• Now you try: Use the Sinatra::Erb::EventContext or Sinatra::Haml::EventContext to do the same. Do them inline and as template files.
• Learn more cool stuff: see Sinatra::Dsl
• Create your own plugins!
  1. Create a ‘vendor’ directory in your app directory
  2. Lay it out like: myapp.rb : root

        |- vendor
     
                     | - plugin_name
     
                   | - init.rb  # load and hook here
     
                   | - lib
     
                         |- modules/classes here

  3. Use it in your app!

For further details visit:

• http://sinatra.rubyforge.org/doc/
• http://www.xnot.org/sinatra
• http://del.icio.us/tag/sinatra

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