Implement #login! helper

Author: Spone

README.md

@@ -55,6 +55,7 @@ explaining and the rest are commented:
 ```ruby
 require_login # This is a before action
 login(email, password, remember_me = false)
+login!(email, password, remember_me = false) # Raises an `Sorcery::InvalidCredentials` exception on failure
 auto_login(user) # Login without credentials
 logout
 logged_in? # Available in views

lib/sorcery/controller.rb

@@ -1,4 +1,6 @@
 module Sorcery
+  class InvalidCredentials < StandardError; end
+
   module Controller
     def self.included(klass)
       klass.class_eval do
@@ -63,6 +65,16 @@ def login(*credentials)
         end
       end
 
+      def login!(*credentials)
+        user = login(*credentials)
+
+        if user.nil?
+          raise Sorcery::InvalidCredentials
+        else
+          user
+        end
+      end
+
       def reset_sorcery_session
         reset_session # protect from session fixation attacks
       end

spec/controllers/controller_spec.rb

@@ -85,6 +85,39 @@
       end
     end
 
+    describe '#login!' do
+      context 'when succeeds' do
+        before do
+          expect(User).to receive(:authenticate).with('[email protected]', 'secret') { |&block| block.call(user, nil) }
+          get :test_login_bang, params: { email: '[email protected]', password: 'secret' }
+        end
+
+        it 'assigns user to @user variable' do
+          expect(assigns[:user]).to eq user
+        end
+
+        it 'writes user id in session' do
+          expect(session[:user_id]).to eq user.id.to_s
+        end
+
+        it 'sets csrf token in session' do
+          expect(session[:_csrf_token]).not_to be_nil
+        end
+      end
+
+      context 'when fails' do
+        before do
+          expect(User).to receive(:authenticate).with('[email protected]', 'opensesame!').and_return(nil)
+        end
+
+        it 'raises Sorcery::InvalidCredentials exception' do
+          expect do
+            get :test_login_bang, params: { email: '[email protected]', password: 'opensesame!' }
+          end.to raise_error(Sorcery::InvalidCredentials)
+        end
+      end
+    end
+
     describe '#logout' do
       it 'clears the session' do
         cookies[:remember_me_token] = nil

spec/rails_app/app/controllers/sorcery_controller.rb

@@ -28,6 +28,11 @@ def test_login
     head :ok
   end
 
+  def test_login_bang
+    @user = login!(params[:email], params[:password])
+    head :ok
+  end
+
   def test_auto_login
     @user = User.first
     auto_login(@user)

spec/rails_app/config/routes.rb

@@ -3,6 +3,7 @@
 
   controller :sorcery do
     get :test_login
+    get :test_login_bang
     get :test_logout
     get :some_action
     post :test_return_to