finished

source/Gemfile

@@ -1,6 +1,6 @@
 source 'https://rubygems.org'
 
-
+gem 'pry'
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '4.1.6'
 # Use sqlite3 as the database for Active Record

source/Gemfile.lock

@@ -29,6 +29,7 @@ GEM
       tzinfo (~> 1.1)
     arel (5.0.1.20140414130214)
     builder (3.2.2)
+    coderay (1.1.2)
     coffee-rails (4.0.1)
       coffee-script (>= 2.2.0)
       railties (>= 4.0.0, < 5.0)
@@ -50,9 +51,13 @@ GEM
     json (1.8.1)
     mail (2.6.1)
       mime-types (>= 1.16, < 3)
+    method_source (0.9.0)
     mime-types (2.4.1)
     minitest (5.4.2)
     multi_json (1.10.1)
+    pry (0.11.3)
+      coderay (~> 1.1.0)
+      method_source (~> 0.9.0)
     rack (1.5.2)
     rack-test (0.6.2)
       rack (>= 1.0)
@@ -128,6 +133,7 @@ DEPENDENCIES
   coffee-rails (~> 4.0.0)
   jbuilder (~> 2.0)
   jquery-rails
+  pry
   rails (= 4.1.6)
   rspec-rails
   sass-rails (~> 4.0.3)
@@ -136,3 +142,6 @@ DEPENDENCIES
   sqlite3
   turbolinks
   uglifier (>= 1.3.0)
+
+BUNDLED WITH
+   1.16.1

source/app/controllers/urls_controller.rb

@@ -1,2 +1,35 @@
 class UrlsController < ApplicationController
+
+  def short
+    @url = Url.find_by(:short_url => params[:id])
+    @url.increment(:click_count)
+    redirect_to @url[:long_url]
+  end
+
+  def index
+    @urls = Url.all
+  end
+
+  def show
+    @url = Url.find(params[:id])
+    url_path(@url)
+  end
+
+  def new
+    @url = Url.new
+  end
+
+  def create
+    @url = Url.new(url_params)
+    if @url.save
+        redirect_to url_path(@url)
+    else
+      render 'new' 
+    end
+  end
+
+  private
+    def url_params
+      params.require(:url).permit(:long_url)
+    end
 end

source/app/models/url.rb

@@ -0,0 +1,20 @@
+require 'net/http'
+
+class Url < ActiveRecord::Base
+  before_create :shorten_url
+  validates :long_url, presence: true, allow_blank: false
+  validate :validate_url
+
+  def validate_url
+    uri = URI("#{self.long_url}")
+    # this doesn't work if the input isn't a url, i.e., it only works if an error code is returned
+    if res = Net::HTTP.get_response(uri)
+    else res.code = "x"
+    end
+    self.errors.add(:base, "This URL is invalid, #{res.message}") if res.code != "200"
+  end
+
+  def shorten_url
+    self.short_url = "!#{(0..3).map{ rand(36).to_s(36) }.join}"
+  end
+end

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

@@ -0,0 +1,5 @@
+<h1>All the URLs</h1>
+
+<% @urls.each do |url| %>
+  <%= url.long_url %><br />
+<% end %>

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

@@ -0,0 +1,11 @@
+<% if @url.errors.any? %>
+  <% @url.errors.full_messages.each do |message| %>
+    <li><%= message %></li>
+  <% end %>
+<% end %>
+
+<%= form_for @url do |f| %>
+  <%= f.label "Enter a URL" %>
+  <%= f.url_field :long_url, :required => true %>
+<%= f.submit %>
+<% end %>

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

@@ -0,0 +1,2 @@
+The URL you entered: <%= @url.long_url %><br />
+Its short version: <%= link_to "http://localhost:3000/urls/#{@url.short_url}", @url.short_url %>

source/config/application.rb

@@ -5,6 +5,7 @@
 # Require the gems listed in Gemfile, including any gems
 # you've limited to :test, :development, or :production.
 Bundler.require(*Rails.groups)
+require 'pry'
 
 module Source
   class Application < Rails::Application

source/config/routes.rb

@@ -1,4 +1,10 @@
 Rails.application.routes.draw do
+
+  get 'urls/:id', to: 'urls#short', id: /[:!].{4}/
+
+  resources :urls
+
+
   # 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/20180514183131_urls.rb

@@ -0,0 +1,8 @@
+class Urls < ActiveRecord::Migration
+  def change
+    create_table :urls do |t|
+      t.string :long_url
+      t.string :short_url
+    end
+  end
+end

source/db/migrate/20180515131738_add_click_count_to_urls.rb

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

source/db/schema.rb

@@ -0,0 +1,22 @@
+# 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: 20180515131738) do
+
+  create_table "urls", force: true do |t|
+    t.string  "long_url"
+    t.string  "short_url"
+    t.integer "click_count", default: 0
+  end
+
+end