Getting to know Sinatra « Start the Insanity…

For one of my clients I’ve been tasked to create a web-based testing tool that will be used to test a JSON-message-enabled Service. I asked my friends and was pointed to Sinatra.

I perused the website and thought, “Wow, that looks really easy.” So I then started thinking about the requirements for the testing tool. Aside from the pretty bits, the tool has to:

send and receive from a socket
send and receive json
read from the filesystem
display printable results (aka the pretty bits)

So, in true XP fashion, I set out to build a Spike to research numbers 1 and 2. Aside from the dependencies, I had a no-frills Spike with only 3 files. Not too bad, huh?

Implementation

Dependencies

sudo gem install json
sudo gem install rack
sudo gem install sinatra

View Files

layout.erb

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
  <meta http-equiv="content-type" content="text/html;charset=UTF-8" />
  <title>Frank</title>
</head>
<body>
  <div class="container">
    <div id="header">
      <h1>Frank</h1>
    </div>

    <div id="content">
      <%= yield %>
    </div>
  </div>

</body>
</html>

index.erb

<h2>Basic NORM Test Harness</h2>
<form action="/" method="post" accept-charset="utf-8">
  <p><label for="line1">Line 1: </label><input type="text" name="line1" value="" id="line1"></p>
  <p><label for="line2">Line 2: </label><input type="text" name="line2" value="" id="line2"></p>
  <p><label for="city">City: </label><input type="text" name="city" value="" id="city"></p>
  <p><label for="state">State: </label><input type="text" name="state" value="" id="state"></p>
  <p><label for="zip">Zip: </label><input type="text" name="zip" value="" id="zip"></p>

  <p><input type="submit" value="Continue &rarr;"></p>
</form>

<div>
  <pre><%= @result %></pre>
</div>

Controller

myapp.rb

# myapp.rb
require 'rubygems'
require 'sinatra'
require 'json'

server  = 'localhost'
port    = 40000

get '/' do
  erb :index
end

post '/' do
  message   = {
    "line1" => params[:line1],
    "line2" => params[:line2],
    "city"  => params[:city],
    "state" => params[:state],
    "zip"   => params[:zip]
    }

  socket = TCPSocket.new(server, port)
  socket.puts JSON.generate(message)
  socket.flush

  output = ""
  while(response = socket.gets)
    output += response
  end
  socket.close

  @result = output

  erb :index
end

No Fuss! No Muss!

I have a feeling any medium to large application will require some careful forethought when using Sinatra. For my purposes though, Sinatra fits the bill. If you have a small-ish application give Sinatra a look; you might be pleasantly surprised how quickly you get up and running.

Cheers!