unfurler.heroku.com

README

The Unfurler!
=============

## What is it?

You give it a shortened url and it looks up where it would take you. There is a
version running at http://unfurler.heroku.com if you want to try it out.

## How do I run it?

$ bundle install
$ shotgun

## How do I deploy it?

$ gem install heroku
$ heroku create
$ git push heroku master
$ heroku open

## How do I use it?

Navigate to http://localhost:9393/ and type in a shortend url. You can also just
use the address bar like so: http://localhost:9393/u/bit.ly/ieHELP

## API?

There is a json api, believe it or not. Just use /j/ instead of /u/ to get json
back, like so: http://localhost:9393/j/bit.ly/ieHELP

To do this with jQuery, this would look like:

    $.get('http://localhost:9393/j/bit.ly/ieHELP', {}, function(data) {
      console.log(JSON.stringify(data))
    }, "json")

or if you want to use a `script` tag and have it fire a callback, you can do:

    <script>
      function foo(json) {
        alert(JSON.stringify(json));
      }

      node = document.createElement('script');
      node.src = "http://unfurler.heroku.com/j/bit.ly/ieHELP?callback=foo";
      document.body.appendChild(node); // this loads and runs the script
    </script>

If you want it to run on page load, just put it in a script tag manually like so:

    <!-- define `foo` in a script tag before this one -->
    <script src="http://unfurler.heroku.com/j/bit.ly/ieHELP?callback=foo"></script>

The callback is provided to help get around XSS protections.

config.ru

require 'sinatra'
require 'httparty'
require 'haml'
require 'json'

set :haml, :format => :html5

class Unfurler
  attr_accessor :redirects, :protocol, :url, :response

  def initialize new_url
    self.url, self.redirects = new_url, []
  end

  def url= new_url
    @protocol = if proto = new_url.match(%r{^(http[s]*://)})
      proto[1]
    else
      "http://"
    end

    @url = new_url.gsub %r{^http[s]*://}, ''
  end

  def full_url
    protocol + url
  end

  def head
    HTTParty.head full_url, follow_redirects: false
  end

  def fetch!
    @response = head
    if @response.code.to_s =~ /30[12]/
      @redirects << response.headers['location']
      unfurler = self.class.new(@redirects.last).fetch!
      @redirects.concat unfurler.redirects
    end
    self # return self so it's chainable
  end
end

helpers do
  def title new_title
    @title = new_title
  end

  def partial name, locals = {}
    haml name.to_sym, :layout => false, :locals => locals
  end
end

get '/' do
  title 'Home'
  haml :index
end

get '/u/*', :provides => 'html' do
  expires 604800, :public # cache for a week

  # :url and :splat to support js and non-js users
  url_param = params[:url] || (params[:splat] || []).join("/")
  throw 404 if url_param.nil? || url_param.empty?
  @unfurler = Unfurler.new(url_param).fetch!
  title "Unfurling #{@unfurler.url}"
  if @unfurler.redirects.empty?
    haml :not_a_redirect
  else
    haml :unfurled
  end
end

get '/j/*' do
  content_type :json
  @url_to_request = params[:splat].join("/").gsub(/http:\/\//, '')
  @url_response = Unfuler.new(@url_to_request).head
  json = @url_response.headers.to_hash.to_json
  unless params[:callback].nil? || params[:callback].empty?
    json = params[:callback] + "(#{json})"
  end
  json
end

get '/style.css' do
  content_type :css
  erb :stylesheet, layout: false
end

get '/site.js' do
  content_type :js
  erb :javascript, layout: false
end

template :layout do
%q{
!!!
%html
  %head
    %title= "#{@title} - Unfurler"
    %link(rel="stylesheet" href="/style.css")
    %link(rel="shortcut icon" href="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAIAAACQkWg2AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAKBJREFUeNpidHNzYyAFMDGQCGivgQWIAwMD5eTkJk6cCBGCc/Pz8zU0NOBKb9y4ARQEaQBKI0ugcdevXw9hfPv2DWoDfrBr1y50J+EH8HA/d+7cmzdvCGvQ1NSE+4EoG+CBgQjW69evA8no6GigX4EOAJIQw3AG65EjR4D22oABkAt0KDxkMAEj3E8iYAAMu0ePHhGIOAh4AwaDIC0BBBgAvws9sktyKQMAAAAASUVORK5CYII=")
  %body
    %h1
      %a(href="/") The Unfurler!
    = yield
    %script(src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.1/jquery.min.js")
    %script(src="/site.js")
}
end

template :index do
%q{
%form#the-form(action="/u/")
  %p
    %label(for="url") URL to unfurl:
    %input(name="url" id="url" placeholder="URL to unfurl" autofocus)

  %p
    %button(type="submit") Unfurl
}
end

template :unfurled do
%q{
%p
  You provided
  %a(href="#{@unfurler.full_url}")= @unfurler.url
  
  - @unfurler.redirects.each do |r|
    = partial(:redirect, redirect: r)
}
end

template :redirect do
%q{
which redirects to
%a(href="#{redirect}")= redirect
}
end

template :not_a_redirect do
%q{
%p
  You provided
  %a(href="#{@unfurler.full_url}")= @unfurler.url
  which doesn't redirect anywhere.
}
end

template :stylesheet do
%q[
html { background: #eee; }
body {
  width: 500px;
  margin: 0 auto;
  padding: 20px;
  background: #fff;
  -webkit-box-shadow: 0 1px 9px rgba(0,0,0,0.1);
  -moz-box-shadow: 0 1px 9px rgba(0,0,0,0.1);
  box-shadow: 0 1px 9px rgba(0,0,0,0.1);
  font: 16px/1.6 Helvetica Neue, Arial, sans-serif;
  color: #333;
}
h1 { text-align: center; }
h1, p { margin: 0 0 1em; }
h1 a {
  color: #333;
  text-decoration: none;
}
h1 a:hover { color: #000; }
body.loaded label { display: none; }
input {
  width: 400px;
  font: 16px/1.3 Helvetica Neue, Arial, sans-serif;
}
form p { text-align: center; }
]
end

template :javascript do
%q@
document.body.className = "loaded";

if (document.getElementById('the-form')) {
  document.getElementById('the-form').onsubmit = function(event) {
    var url = document.getElementsByTagName('input')[0].value;
    window.location = window.location.protocol + "//" + 
      window.location.host + "/u/" + url.replace(/http:\/\//, '');
    return false;
  };
}
@
end

run Sinatra::Application

Gemfile

source :rubygems
gem 'sinatra'
gem 'httparty'
gem 'haml'
gem 'json'

group :development do
  gem 'shotgun'
end

Gemfile.lock

GEM
  remote: http://rubygems.org/
  specs:
    crack (0.1.8)
    haml (3.1.2)
    httparty (0.7.8)
      crack (= 0.1.8)
    json (1.5.3)
    rack (1.3.0)
    shotgun (0.9)
      rack (>= 1.0)
    sinatra (1.2.6)
      rack (~> 1.1)
      tilt (< 2.0, >= 1.2.2)
    tilt (1.3.2)

PLATFORMS
  ruby

DEPENDENCIES
  haml
  httparty
  json
  shotgun
  sinatra