Introduce ExpiringToken, a base for future authentication

app/models/expiring_token.rb

@@ -0,0 +1,28 @@
+class ExpiringToken < ActiveRecord::Base
+
+  belongs_to :user
+
+  validates :user, :token, :expires_at, presence: true
+
+  scope :active, -> { where(used_at: nil).where('expires_at > ?', Time.now) }
+
+  def self.create_for_user(user)
+    create!(
+      user: user,
+      token: SecureRandom.urlsafe_base64,
+      expires_at: 15.minutes.from_now
+    )
+  end
+
+  def self.active_for_token(token)
+    active.where(token: token).first
+  end
+
+  def use!
+    raise "token #{token} already used at #{used_at}" if used_at
+
+    self.used_at = Time.now
+    save!
+  end
+
+end

app/models/user.rb

@@ -9,6 +9,7 @@ class User < ActiveRecord::Base
   has_many :api_tokens, :dependent => :destroy
   has_many :asciicasts, :dependent => :destroy
   has_many :comments, :dependent => :destroy
+  has_many :expiring_tokens, dependent: :destroy
 
   validates :username, uniqueness: { case_sensitive: false },
                        format: { with: USERNAME_FORMAT },

db/migrate/20141004124152_create_auth_codes.rb

@@ -0,0 +1,13 @@
+class CreateAuthCodes < ActiveRecord::Migration
+  def change
+    create_table :auth_codes do |t|
+      t.references :user, index: true, null: false
+      t.string :code, null: false
+      t.datetime :expires_at, null: false
+
+      t.timestamps
+    end
+
+    add_index :auth_codes, [:code, :expires_at]
+  end
+end

db/migrate/20141004165807_add_used_at_to_auth_codes.rb

@@ -0,0 +1,5 @@
+class AddUsedAtToAuthCodes < ActiveRecord::Migration
+  def change
+    add_column :auth_codes, :used_at, :datetime
+  end
+end

db/migrate/20141004165838_remove_updated_at_from_auth_codes.rb

@@ -0,0 +1,5 @@
+class RemoveUpdatedAtFromAuthCodes < ActiveRecord::Migration
+  def change
+    remove_column :auth_codes, :updated_at
+  end
+end

db/migrate/20141004170135_update_auth_codes_index.rb

@@ -0,0 +1,6 @@
+class UpdateAuthCodesIndex < ActiveRecord::Migration
+  def change
+    remove_index :auth_codes, name: "index_auth_codes_on_code_and_expires_at"
+    add_index :auth_codes, [:used_at, :expires_at, :code]
+  end
+end

db/migrate/20141005100915_rename_auth_codes_to_temporary_tokens.rb

@@ -0,0 +1,5 @@
+class RenameAuthCodesToTemporaryTokens < ActiveRecord::Migration
+  def change
+    rename_table :auth_codes, :temporary_tokens
+  end
+end

db/migrate/20141005101420_rename_temporary_tokens_code_to_token.rb

@@ -0,0 +1,5 @@
+class RenameTemporaryTokensCodeToToken < ActiveRecord::Migration
+  def change
+    rename_column :temporary_tokens, :code, :token
+  end
+end

db/migrate/20141005103646_rename_temporary_tokens_to_expiring_tokens.rb

@@ -0,0 +1,5 @@
+class RenameTemporaryTokensToExpiringTokens < ActiveRecord::Migration
+  def change
+    rename_table :temporary_tokens, :expiring_tokens
+  end
+end

db/schema.rb

@@ -72,6 +72,17 @@ ActiveRecord::Schema.define(version: 20141005152615) do
   add_index "comments", ["asciicast_id"], name: "index_comments_on_asciicast_id", using: :btree
   add_index "comments", ["user_id"], name: "index_comments_on_user_id", using: :btree
 
+  create_table "expiring_tokens", force: true do |t|
+    t.integer  "user_id",    null: false
+    t.string   "token",      null: false
+    t.datetime "expires_at", null: false
+    t.datetime "created_at"
+    t.datetime "used_at"
+  end
+
+  add_index "expiring_tokens", ["used_at", "expires_at", "token"], name: "index_expiring_tokens_on_used_at_and_expires_at_and_token", using: :btree
+  add_index "expiring_tokens", ["user_id"], name: "index_expiring_tokens_on_user_id", using: :btree
+
   create_table "likes", force: true do |t|
     t.integer  "asciicast_id", null: false
     t.integer  "user_id",      null: false

spec/factories/expiring_tokens.rb

@@ -0,0 +1,17 @@
+# Read about factories at http://github.com/thoughtbot/factory_girl
+
+FactoryGirl.define do
+  factory :expiring_token do
+    association :user
+    sequence(:token) { |n| "token-#{n}" }
+    expires_at { 10.minutes.from_now }
+  end
+
+  factory :used_expiring_token, parent: :expiring_token do
+    used_at { 1.minute.ago }
+  end
+
+  factory :expired_expiring_token, parent: :expiring_token do
+    expires_at { 1.minute.ago }
+  end
+end

spec/models/expiring_token_spec.rb

@@ -0,0 +1,47 @@
+require 'rails_helper'
+
+RSpec.describe ExpiringToken, :type => :model do
+
+  it { should validate_presence_of(:user) }
+  it { should validate_presence_of(:token) }
+  it { should validate_presence_of(:expires_at) }
+
+  describe '.create_for_user' do
+    it 'creates expiring token with generated token and expiration time in the future' do
+      user = create(:user)
+
+      expiring_token = ExpiringToken.create_for_user(user)
+
+      expect(expiring_token.user).to eq(user)
+      expect(expiring_token.token.size).to eq(22)
+      expect(expiring_token.expires_at).to be > Time.now
+    end
+  end
+
+  describe '.active_for_token' do
+    it 'returns not used and not expired expiring token matching given token' do
+      used_expiring_token = create(:used_expiring_token)
+      expired_expiring_token = create(:expired_expiring_token)
+      good_expiring_token = create(:expiring_token)
+
+      expect(ExpiringToken.active_for_token(used_expiring_token.token)).to be(nil)
+      expect(ExpiringToken.active_for_token(expired_expiring_token.token)).to be(nil)
+      expect(ExpiringToken.active_for_token(good_expiring_token.token)).to eq(good_expiring_token)
+    end
+  end
+
+  describe '#use!' do
+    it 'sets used_at to the current time and saves the record' do
+      expiring_token = create(:expiring_token)
+      now = Time.now
+
+      Timecop.freeze(now) do
+        expiring_token.use!
+      end
+
+      expect(expiring_token.used_at).to eq(now)
+      expect(expiring_token).to_not be_changed
+    end
+  end
+
+end