Replace homegrown slug with friendly_id

Gemfile

@@ -20,6 +20,8 @@ gem 'slim-rails'
 gem 'bootstrap-sass'
 gem 'simple_form'
 
+gem 'friendly_id', '~> 5.1.0'
+
 gem 'bcrypt'
 
 gem 'sdoc', '~> 0.4.0', group: :doc

Gemfile.lock

@@ -125,6 +125,8 @@ GEM
       ruby_parser (~> 3.1, > 3.1.0)
       sexp_processor (~> 4.4)
     formatador (0.2.5)
+    friendly_id (5.1.0)
+      activerecord (>= 4.0.0)
     globalid (0.3.5)
       activesupport (>= 4.1.0)
     guard (2.12.8)
@@ -375,6 +377,7 @@ DEPENDENCIES
   dotenv-rails
   factory_girl_rails
   faker
+  friendly_id (~> 5.1.0)
   guard-rspec
   jbuilder (~> 2.0)
   jquery-rails

app/controllers/subcreddits_controller.rb

@@ -45,6 +45,6 @@ class SubcredditsController < ApplicationController
   end
 
   def set_subcreddit
-    @subcreddit = Subcreddit.find_by_slug(params[:id])
+    @subcreddit = Subcreddit.friendly.find(params[:id])
   end
 end

app/models/subcreddit.rb

@@ -1,28 +1,25 @@
-RESERVED_SLUGS = %w(new edit)
-
 class Subcreddit < ActiveRecord::Base
+  extend FriendlyId
+
   belongs_to :owner, class_name: 'User'
   has_many :posts
 
+  friendly_id :name, use: :slugged
+
   attr_accessor :closed
 
-  before_save :set_slug
   before_save :set_closed_at
 
   validates :name,
     presence: true,
     format: /\A(?! )[a-z0-9 ]*(?<! )\z/i,
-    uniqueness: { case_sensitive: false },
+    uniqueness: true, #{ case_sensitive: false },
     length: { minimum: 3, maximum: 21 }
 
-  validate :slug_is_not_a_route
-
   validates :closed,
     format: /\A[01]?\z/
 
-  def to_param
-    self.slug
-  end
+  validate :slug_does_not_have_uuid
 
   def closed?
     self.closed_at != nil
@@ -30,14 +27,6 @@ class Subcreddit < ActiveRecord::Base
 
   private
 
-  def set_slug
-    self.slug = sluggify_name
-  end
-
-  def sluggify_name
-    self.name.downcase.tr(' ', '_')
-  end
-
   def set_closed_at
     if closed == '1' && closed_at == nil
       self.closed_at = Time.now
@@ -46,9 +35,9 @@ class Subcreddit < ActiveRecord::Base
     end
   end
 
-  def slug_is_not_a_route
-    if RESERVED_SLUGS.include?(sluggify_name)
-      errors.add(:name, 'cannot be a reserved keyword')
+  def slug_does_not_have_uuid
+    if self.slug.match /([a-z0-9]+\-){4}[a-z0-9]+\z/
+      errors.add(:name, 'must be unique')
     end
   end
 end

config/initializers/friendly_id.rb

@@ -0,0 +1,88 @@
+# FriendlyId Global Configuration
+#
+# Use this to set up shared configuration options for your entire application.
+# Any of the configuration options shown here can also be applied to single
+# models by passing arguments to the `friendly_id` class method or defining
+# methods in your model.
+#
+# To learn more, check out the guide:
+#
+# http://norman.github.io/friendly_id/file.Guide.html
+
+FriendlyId.defaults do |config|
+  # ## Reserved Words
+  #
+  # Some words could conflict with Rails's routes when used as slugs, or are
+  # undesirable to allow as slugs. Edit this list as needed for your app.
+  config.use :reserved
+
+  config.reserved_words = %w(new edit index session login logout users admin
+    stylesheets assets javascripts images)
+
+  #  ## Friendly Finders
+  #
+  # Uncomment this to use friendly finders in all models. By default, if
+  # you wish to find a record by its friendly id, you must do:
+  #
+  #    MyModel.friendly.find('foo')
+  #
+  # If you uncomment this, you can do:
+  #
+  #    MyModel.find('foo')
+  #
+  # This is significantly more convenient but may not be appropriate for
+  # all applications, so you must explicity opt-in to this behavior. You can
+  # always also configure it on a per-model basis if you prefer.
+  #
+  # Something else to consider is that using the :finders addon boosts
+  # performance because it will avoid Rails-internal code that makes runtime
+  # calls to `Module.extend`.
+  #
+  # config.use :finders
+  #
+  # ## Slugs
+  #
+  # Most applications will use the :slugged module everywhere. If you wish
+  # to do so, uncomment the following line.
+  #
+  # config.use :slugged
+  #
+  # By default, FriendlyId's :slugged addon expects the slug column to be named
+  # 'slug', but you can change it if you wish.
+  #
+  # config.slug_column = 'slug'
+  #
+  # When FriendlyId can not generate a unique ID from your base method, it appends
+  # a UUID, separated by a single dash. You can configure the character used as the
+  # separator. If you're upgrading from FriendlyId 4, you may wish to replace this
+  # with two dashes.
+  #
+  # config.sequence_separator = '-'
+  #
+  #  ## Tips and Tricks
+  #
+  #  ### Controlling when slugs are generated
+  #
+  # As of FriendlyId 5.0, new slugs are generated only when the slug field is
+  # nil, but if you're using a column as your base method can change this
+  # behavior by overriding the `should_generate_new_friendly_id` method that
+  # FriendlyId adds to your model. The change below makes FriendlyId 5.0 behave
+  # more like 4.0.
+  #
+  # config.use Module.new {
+  #   def should_generate_new_friendly_id?
+  #     slug.blank? || <your_column_name_here>_changed?
+  #   end
+  # }
+  #
+  # FriendlyId uses Rails's `parameterize` method to generate slugs, but for
+  # languages that don't use the Roman alphabet, that's not usually sufficient.
+  # Here we use the Babosa library to transliterate Russian Cyrillic slugs to
+  # ASCII. If you use this, don't forget to add "babosa" to your Gemfile.
+  #
+  # config.use Module.new {
+  #   def normalize_friendly_id(text)
+  #     text.to_slug.normalize! :transliterations => [:russian, :latin]
+  #   end
+  # }
+end

db/migrate/20150716045747_create_friendly_id_slugs.rb

@@ -0,0 +1,15 @@
+class CreateFriendlyIdSlugs < ActiveRecord::Migration
+  def change
+    create_table :friendly_id_slugs do |t|
+      t.string   :slug,           :null => false
+      t.integer  :sluggable_id,   :null => false
+      t.string   :sluggable_type, :limit => 50
+      t.string   :scope
+      t.datetime :created_at
+    end
+    add_index :friendly_id_slugs, :sluggable_id
+    add_index :friendly_id_slugs, [:slug, :sluggable_type]
+    add_index :friendly_id_slugs, [:slug, :sluggable_type, :scope], :unique => true
+    add_index :friendly_id_slugs, :sluggable_type
+  end
+end

db/migrate/20150716050055_add_index_to_subcreddit_slug.rb

@@ -0,0 +1,5 @@
+class AddIndexToSubcredditSlug < ActiveRecord::Migration
+  def change
+    add_index :subcreddits, :slug, unique: true
+  end
+end

db/schema.rb

@@ -11,7 +11,20 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20150714200610) do
+ActiveRecord::Schema.define(version: 20150716050055) do
+
+  create_table "friendly_id_slugs", force: :cascade do |t|
+    t.string   "slug",                      null: false
+    t.integer  "sluggable_id",              null: false
+    t.string   "sluggable_type", limit: 50
+    t.string   "scope"
+    t.datetime "created_at"
+  end
+
+  add_index "friendly_id_slugs", ["slug", "sluggable_type", "scope"], name: "index_friendly_id_slugs_on_slug_and_sluggable_type_and_scope", unique: true
+  add_index "friendly_id_slugs", ["slug", "sluggable_type"], name: "index_friendly_id_slugs_on_slug_and_sluggable_type"
+  add_index "friendly_id_slugs", ["sluggable_id"], name: "index_friendly_id_slugs_on_sluggable_id"
+  add_index "friendly_id_slugs", ["sluggable_type"], name: "index_friendly_id_slugs_on_sluggable_type"
 
   create_table "posts", force: :cascade do |t|
     t.integer  "user_id"
@@ -36,6 +49,7 @@ ActiveRecord::Schema.define(version: 20150714200610) do
   end
 
   add_index "subcreddits", ["owner_id"], name: "index_subcreddits_on_owner_id"
+  add_index "subcreddits", ["slug"], name: "index_subcreddits_on_slug", unique: true
 
   create_table "user_sessions", force: :cascade do |t|
     t.integer  "user_id"

spec/models/subcreddit_spec.rb

@@ -1,5 +1,7 @@
 require 'rails_helper'
 
+require 'securerandom'
+
 describe Subcreddit, type: :model do
   let(:subcreddit) { build(:subcreddit) }
 
@@ -15,12 +17,6 @@ describe Subcreddit, type: :model do
       expect(subcreddit).to be_valid
     end
 
-    it 'should sluggify the name' do
-      subcreddit.name = 'Testing Spaces 1'
-      subcreddit.save
-      expect(subcreddit.slug).to eq('testing_spaces_1')
-    end
-
     it 'should set closed_at if closed is true and closed_at is nil' do
       Timecop.freeze do
         subcreddit.closed = '1'
@@ -92,15 +88,8 @@ describe Subcreddit, type: :model do
       expect(duplicate).to be_invalid
     end
 
-    it 'should not allow duplicate names (case insensitive)' do
-      original = create(:subcreddit)
-      duplicate = build(:subcreddit, name: original.name.upcase)
-
-      expect(duplicate).to be_invalid
-    end
-
-    it 'should not use a reserved keyword' do
-      subcreddit.name = 'New'
+    it 'should not allow a slug with a UUID' do
+      subcreddit.slug = "test-#{SecureRandom.uuid}"
 
       expect(subcreddit).to be_invalid
     end