robert lude's solution

source/.gitignore

@@ -14,3 +14,7 @@
 # Ignore all logfiles and tempfiles.
 /log/*.log
 /tmp
+
+# Ignore vim tempfiles
+*.swo
+*.swp

source/app/assets/stylesheets/scaffolds.css.scss

@@ -0,0 +1,69 @@
+body {
+  background-color: #fff;
+  color: #333;
+  font-family: verdana, arial, helvetica, sans-serif;
+  font-size: 13px;
+  line-height: 18px;
+}
+
+p, ol, ul, td {
+  font-family: verdana, arial, helvetica, sans-serif;
+  font-size: 13px;
+  line-height: 18px;
+}
+
+pre {
+  background-color: #eee;
+  padding: 10px;
+  font-size: 11px;
+}
+
+a {
+  color: #000;
+  &:visited {
+    color: #666;
+  }
+  &:hover {
+    color: #fff;
+    background-color: #000;
+  }
+}
+
+div {
+  &.field, &.actions {
+    margin-bottom: 10px;
+  }
+}
+
+#notice {
+  color: green;
+}
+
+.field_with_errors {
+  padding: 2px;
+  background-color: red;
+  display: table;
+}
+
+#error_explanation {
+  width: 450px;
+  border: 2px solid red;
+  padding: 7px;
+  padding-bottom: 0;
+  margin-bottom: 20px;
+  background-color: #f0f0f0;
+  h2 {
+    text-align: left;
+    font-weight: bold;
+    padding: 5px 5px 5px 15px;
+    font-size: 12px;
+    margin: -7px;
+    margin-bottom: 0px;
+    background-color: #c00;
+    color: #fff;
+  }
+  ul li {
+    font-size: 12px;
+    list-style: square;
+  }
+}

source/app/assets/stylesheets/urls.css.scss

@@ -1,3 +1,14 @@
-// Place all the styles related to the Urls controller here.
+// Place all the styles related to the urls controller here.
 // They will automatically be included in application.css.
 // You can use Sass (SCSS) here: http://sass-lang.com/
+
+.urls {
+  table {
+    border-collapse: collapse;
+    tr {
+      td {
+        padding: 1em;
+      }
+    }
+  }
+}

source/app/controllers/urls_controller.rb

@@ -1,2 +1,81 @@
 class UrlsController < ApplicationController
+  before_action :set_url, only: [:show, :edit, :update, :destroy]
+
+  # GET /urls
+  # GET /urls.json
+  def index
+    @urls = Url.all
+  end
+
+  # GET /urls/1
+  # GET /urls/1.json
+  def show
+  end
+
+  # GET /urls/new
+  def new
+    @url = Url.new
+  end
+
+  # GET /urls/1/edit
+  def edit
+  end
+
+  def goto
+    id = Url.decode_shortcode params[:shortcode]
+    url = Url.find id
+    url.click_count += 1
+    url.save!
+    redirect_to url.destination
+  end
+  # POST /urls
+  # POST /urls.json
+  def create
+    @url = Url.new(url_params)
+
+    respond_to do |format|
+      if @url.save
+        format.html { redirect_to @url, notice: 'Url was successfully created.' }
+        format.json { render :show, status: :created, location: @url }
+      else
+        format.html { render :new }
+        format.json { render json: @url.errors, status: :unprocessable_entity }
+      end
+    end
+  end
+
+  # PATCH/PUT /urls/1
+  # PATCH/PUT /urls/1.json
+  def update
+    respond_to do |format|
+      if @url.update(url_params)
+        format.html { redirect_to @url, notice: 'Url was successfully updated.' }
+        format.json { render :show, status: :ok, location: @url }
+      else
+        format.html { render :edit }
+        format.json { render json: @url.errors, status: :unprocessable_entity }
+      end
+    end
+  end
+
+  # DELETE /urls/1
+  # DELETE /urls/1.json
+  def destroy
+    @url.destroy
+    respond_to do |format|
+      format.html { redirect_to urls_url, notice: 'Url was successfully destroyed.' }
+      format.json { head :no_content }
+    end
+  end
+
+  private
+    # Use callbacks to share common setup or constraints between actions.
+    def set_url
+      @url = Url.find(params[:id])
+    end
+
+    # Never trust parameters from the scary internet, only allow the white list through.
+    def url_params
+      params.require(:url).permit(:shortcode, :destination)
+    end
 end

source/app/helpers/urls_helper.rb

@@ -1,2 +1,3 @@
 module UrlsHelper
+
 end

source/app/models/url.rb

@@ -0,0 +1,22 @@
+
+require 'socket'
+
+class Url < ActiveRecord::Base
+  validates :destination, url: true
+
+  before_validation do
+    self.destination = "http://#{self.destination}" unless /^[a-z]+:/ =~ self.destination
+  end
+
+  def shortcode
+    id.to_s(36)
+  end
+
+  def self.decode_shortcode shortcode
+    shortcode.to_i(36)
+  end
+
+  def shortlink 
+    "http://localhost:3000/#{shortcode}"
+  end
+end

source/app/validators/url_validator.rb

@@ -0,0 +1,24 @@
+
+require 'net/http'
+
+class UrlValidator < ActiveModel::EachValidator
+
+  def validate_each(record, attribute, value)
+    uri = URI(value)
+    return record.errors.add attribute, "must use HTTP or HTTPS" unless ['http','https'].member? uri.scheme
+    begin
+      page_checker = Net::HTTP.new uri.host, uri.port
+      page_checker.use_ssl = uri.scheme.eql? "https"
+      page_checker.start do |http|
+        response = http.head (uri.path.empty? ? "/" : uri.path)
+        puts response.inspect
+        return record.errors.add attribute, "is not a valid address according to their server" unless response.code.to_i < 400
+      end
+    rescue SocketError, Timeout::Error, Errno::EINVAL, Errno::ECONNRESET, EOFError, Net::HTTPBadResponse, Net::HTTPHeaderSyntaxError, Net::ProtocolError => e
+      return record.errors.add attribute, "could not be reached for validation"
+    end
+  rescue URI::InvalidURIError
+    record.errors[attribute] = "does not seem to be a valid URL"
+  end
+
+end

source/app/views/layouts/application.html.erb

@@ -6,7 +6,7 @@
   <%= javascript_include_tag 'application', 'data-turbolinks-track' => true %>
   <%= csrf_meta_tags %>
 </head>
-<body>
+<body class='<%= controller.controller_name %>'>
 
 <%= yield %>
 

source/app/views/urls/_form.html.erb

@@ -0,0 +1,21 @@
+<%= form_for(@url) do |f| %>
+  <% if @url.errors.any? %>
+    <div id="error_explanation">
+      <h2><%= pluralize(@url.errors.count, "error") %> prohibited this url from being saved:</h2>
+
+      <ul>
+      <% @url.errors.full_messages.each do |message| %>
+        <li><%= message %></li>
+      <% end %>
+      </ul>
+    </div>
+  <% end %>
+
+  <div class="field">
+    <%= f.label :destination %><br>
+    <%= f.text_field :destination %>
+  </div>
+  <div class="actions">
+    <%= f.submit %>
+  </div>
+<% end %>

source/app/views/urls/edit.html.erb

@@ -0,0 +1,6 @@
+<h1>Editing url</h1>
+
+<%= render 'form' %>
+
+<%= link_to 'Show', @url %> |
+<%= link_to 'Back', urls_path %>

source/app/views/urls/index.html.erb

@@ -0,0 +1,29 @@
+<h1>Listing urls</h1>
+
+<table>
+  <thead>
+    <tr>
+      <th>Shortcode</th>
+      <th>Clicks</th>
+      <th>Destination</th>
+      <th colspan="3"></th>
+    </tr>
+  </thead>
+
+  <tbody>
+    <% @urls.each do |url| %>
+      <tr>
+        <td><%= url.shortcode %></td>
+        <td><%= url.click_count %></td>
+        <td><%= link_to url.destination, url.destination %></td>
+        <td><%= link_to 'Show', url %></td>
+        <td><%= link_to 'Edit', edit_url_path(url) %></td>
+        <td><%= link_to 'Destroy', url, method: :delete, data: { confirm: 'Are you sure?' } %></td>
+      </tr>
+    <% end %>
+  </tbody>
+</table>
+
+<br>
+
+<%= link_to 'New Url', new_url_path %>

source/app/views/urls/index.json.jbuilder

@@ -0,0 +1,4 @@
+json.array!(@urls) do |url|
+  json.extract! url, :id, :shortcode, :destination
+  json.url url_url(url, format: :json)
+end

source/app/views/urls/new.html.erb

@@ -0,0 +1,5 @@
+<h1>New url</h1>
+
+<%= render 'form' %>
+
+<%= link_to 'Back', urls_path %>

source/app/views/urls/show.html.erb

@@ -0,0 +1,19 @@
+<p id="notice"><%= notice %></p>
+
+<p>
+  <strong>Destination:</strong>
+  <%= link_to @url.destination, @url.destination %>
+</p>
+
+<p>
+  <strong>Shortenened URL:</strong>
+  <%= link_to @url.shortlink, @url.shortlink %>
+</p>
+
+<p>
+  <strong>Clicks:</strong>
+  <%= @url.click_count %>
+</p>
+
+<%= link_to 'Edit', edit_url_path(@url) %> |
+<%= link_to 'Back', urls_path %>

source/app/views/urls/show.json.jbuilder

@@ -0,0 +1 @@
+json.extract! @url, :id, :shortcode, :destination, :created_at, :updated_at

source/config/application.rb

@@ -8,6 +8,7 @@
 
 module Source
   class Application < Rails::Application
+    config.autoload_paths += %W["#{config.root}/app/validators/"]
     # Settings in config/environments/* take precedence over those specified here.
     # Application configuration should go into files in config/initializers
     # -- all .rb files in that directory are automatically loaded.

source/config/routes.rb

@@ -1,4 +1,7 @@
 Rails.application.routes.draw do
+  resources :urls
+  get ':shortcode' => 'urls#goto'
+
   # The priority is based upon order of creation: first created -> highest priority.
   # See how all your routes lay out with "rake routes".
 

source/db/migrate/20150126180838_create_urls.rb

@@ -0,0 +1,10 @@
+class CreateUrls < ActiveRecord::Migration
+  def change
+    create_table :urls do |t|
+      t.string :shortcode
+      t.string :destination
+
+      t.timestamps
+    end
+  end
+end

source/db/migrate/20150126204532_remove_shortcode_from_urls.rb

@@ -0,0 +1,5 @@
+class RemoveShortcodeFromUrls < ActiveRecord::Migration
+  def change
+    remove_column :urls, :shortcode, :string
+  end
+end

source/db/migrate/20150127175240_add_count_to_urls.rb

@@ -0,0 +1,5 @@
+class AddCountToUrls < ActiveRecord::Migration
+  def change
+    add_column :urls, :click_count, :integer, default: 0
+  end
+end

source/db/schema.rb

@@ -0,0 +1,23 @@
+# encoding: UTF-8
+# This file is auto-generated from the current state of the database. Instead
+# of editing this file, please use the migrations feature of Active Record to
+# incrementally modify your database, and then regenerate this schema definition.
+#
+# Note that this schema.rb definition is the authoritative source for your
+# database schema. If you need to create the application database on another
+# system, you should be using db:schema:load, not running all the migrations
+# from scratch. The latter is a flawed and unsustainable approach (the more migrations
+# you'll amass, the slower it'll run and the greater likelihood for issues).
+#
+# It's strongly recommended that you check this file into your version control system.
+
+ActiveRecord::Schema.define(version: 20150127175240) do
+
+  create_table "urls", force: true do |t|
+    t.string   "destination"
+    t.datetime "created_at"
+    t.datetime "updated_at"
+    t.integer  "click_count", default: 0
+  end
+
+end