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Saturday, 24 September 2016
Flexible authentication solution for Rails with Warden- "devise"
Devise is a flexible authentication solution for Rails based on Warden. It:
Is Rack based;
Is a complete MVC solution based on Rails engines;
Allows you to have multiple models signed in at the same time;
Is based on a modularity concept: use only what you really need.
It's composed of 10 modules:
Database Authenticatable: hashes and stores a password in the database to validate the authenticity of a user while signing in. The authentication can be done both through POST requests or HTTP Basic Authentication.
You will usually want to write tests for your changes. To run the test suite, go into Devise's top-level directory and run "bundle install" and "rake". For the tests to pass, you will need to have a MongoDB server (version 2.0 or newer) running on your system.
Starting with Rails?
If you are building your first Rails application, we recommend you do not use Devise. Devise requires a good understanding of the Rails Framework. In such cases, we advise you to start a simple authentication system from scratch. Today, we have three resources that should help you get started:
Once you have solidified your understanding of Rails and authentication mechanisms, we assure you Devise will be very pleasant to work with. 😃
Devise 4.0 works with Rails 4.1 onwards. You can add it to your Gemfile with:
Run the bundle command to install it.
Next, you need to run the generator:
$ rails generate devise:install
At this point, a number of instructions will appear in the console. Among these instructions, you'll need to set up the default URL options for the Devise mailer in each environment. Here is a possible configuration for config/environments/development.rb:
The generator will install an initializer which describes ALL of Devise's configuration options. It is imperative that you take a look at it. When you are done, you are ready to add Devise to any of your models using the generator.
In the following command you will replace MODEL with the class name used for the application’s users (it’s frequently User but could also be Admin). This will create a model (if one does not exist) and configure it with the default Devise modules. The generator also configures your config/routes.rb file to point to the Devise controller.
$ rails generate devise MODEL
Next, check the MODEL for any additional configuration options you might want to add, such as confirmable or lockable. If you add an option, be sure to inspect the migration file (created by the generator if your ORM supports them) and uncomment the appropriate section. For example, if you add the confirmable option in the model, you'll need to uncomment the Confirmable section in the migration.
Then run rake db:migrate
You should restart your application after changing Devise's configuration options. Otherwise, you will run into strange errors, for example, users being unable to login and route helpers being undefined.
Controller filters and helpers
Devise will create some helpers to use inside your controllers and views. To set up a controller with user authentication, just add this before_action (assuming your devise model is 'User'):
For Rails 5, note that protect_from_forgery is no longer prepended to the before_action chain, so if you have set authenticate_user before protect_from_forgery, your request will result in "Can't verify CSRF token authenticity." To resolve this, either change the order in which you call them, or use protect_from_forgery prepend: true.
If your devise model is something other than User, replace "_user" with "_yourmodel". The same logic applies to the instructions below.
To verify if a user is signed in, use the following helper:
For the current signed-in user, this helper is available:
You can access the session for this scope:
After signing in a user, confirming the account or updating the password, Devise will look for a scoped root path to redirect to. For instance, when using a :user resource, the user_root_path will be used if it exists; otherwise, the default root_path will be used. This means that you need to set the root inside your routes:
You can also override after_sign_in_path_for and after_sign_out_path_for to customize your redirect hooks.
Notice that if your Devise model is called Member instead of User, for example, then the helpers available are:
Besides :stretches, you can define :pepper, :encryptor, :confirm_within, :remember_for, :timeout_in, :unlock_in among other options. For more details, see the initializer file that was created when you invoked the "devise:install" generator described above. This file is usually located at /config/initializers/devise.rb.
When you customize your own views, you may end up adding new attributes to forms. Rails 4 moved the parameter sanitization from the model to the controller, causing Devise to handle this concern at the controller as well.
There are just three actions in Devise that allow any set of parameters to be passed down to the model, therefore requiring sanitization. Their names and default permitted parameters are:
sign_in (Devise::SessionsController#create) - Permits only the authentication keys (like email)
sign_up (Devise::RegistrationsController#create) - Permits authentication keys plus password and password_confirmation
account_update (Devise::RegistrationsController#update) - Permits authentication keys plus password, password_confirmation and current_password
In case you want to permit additional parameters (the lazy way™), you can do so using a simple before filter in your ApplicationController:
The above works for any additional fields where the parameters are simple scalar types. If you have nested attributes (say you're using accepts_nested_attributes_for), then you will need to tell devise about those nestings and types. Devise allows you to completely change Devise defaults or invoke custom behaviour by passing a block:
To permit simple scalar values for username and email, use this
devise_parameter_sanitizer.permit(:sign_in) do |user_params|
If you have some checkboxes that express the roles a user may take on registration, the browser will send those selected checkboxes as an array. An array is not one of Strong Parameters' permitted scalars, so we need to configure Devise in the following way:
If you have multiple Devise models, you may want to set up a different parameter sanitizer per model. In this case, we recommend inheriting from Devise::ParameterSanitizer and adding your own logic:
classUser::ParameterSanitizer < Devise::ParameterSanitizerdefinitialize(*)
permit(:sign_up, keys: [:username, :email])
And then configure your controllers to use it:
classApplicationController < ActionController::Baseprotecteddefdevise_parameter_sanitizerif resource_class ==UserUser::ParameterSanitizer.new(User, :user, params)
elsesuper# Use the default oneendendend
The example above overrides the permitted parameters for the user to be both :username and :email. The non-lazy way to configure parameters would be by defining the before filter above in a custom controller. We detail how to configure and customize controllers in some sections below.
We built Devise to help you quickly develop an application that uses authentication. However, we don't want to be in your way when you need to customize it.
Since Devise is an engine, all its views are packaged inside the gem. These views will help you get started, but after some time you may want to change them. If this is the case, you just need to invoke the following generator, and it will copy all views to your application:
$ rails generate devise:views
If you have more than one Devise model in your application (such as User and Admin), you will notice that Devise uses the same views for all models. Fortunately, Devise offers an easy way to customize views. All you need to do is set config.scoped_views = true inside the config/initializers/devise.rb file.
After doing so, you will be able to have views based on the role like users/sessions/new and admins/sessions/new. If no view is found within the scope, Devise will use the default view at devise/sessions/new. You can also use the generator to generate scoped views:
$ rails generate devise:views users
If you would like to generate only a few sets of views, like the ones for the registerable and confirmable module, you can pass a list of modules to the generator with the -v flag.
This is useful for triggering background jobs or logging events during certain actions.
Remember that Devise uses flash messages to let users know if sign in was successful or unsuccessful. Devise expects your application to call flash[:notice] and flash[:alert] as appropriate. Do not print the entire flash hash, print only specific keys. In some circumstances, Devise adds a :timedout key to the flash hash, which is not meant for display. Remove this key from the hash if you intend to print the entire hash.
Devise also ships with default routes. If you need to customize them, you should probably be able to do it through the devise_for method. It accepts several options like :class_name, :path_prefix and so on, including the possibility to change path names for I18n:
If you have the need for more deep customization, for instance to also allow "/sign_in" besides "/users/sign_in", all you need to do is create your routes normally and wrap them in a devise_scope block in the router:
get 'sign_in', to:'devise/sessions#new'end
This way, you tell Devise to use the scope :user when "/sign_in" is accessed. Notice devise_scope is also aliased as as in your router.
Devise uses flash messages with I18n, in conjunction with the flash keys :notice and :alert. To customize your app, you can set up your locale file:
en:devise:sessions:signed_in:'Signed in successfully.'
You can also create distinct messages based on the resource you've configured using the singular name given in routes:
en:devise:sessions:user:signed_in:'Welcome user, you are signed in.'admin:signed_in:'Hello admin!'
The Devise mailer uses a similar pattern to create subject messages:
en:devise:mailer:confirmation_instructions:subject:'Hello everybody!'user_subject:'Hello User! Please confirm your email'reset_password_instructions:subject:'Reset instructions'
Take a look at our locale file to check all available messages. You may also be interested in one of the many translations that are available on our wiki:
If you're using RSpec, you can put the following inside a file named spec/support/devise.rb or in your spec/spec_helper.rb (or spec/rails_helper.rb if you are using rspec-rails):
RSpec.configure do |config|
Just be sure that this inclusion is made after the require 'rspec/rails' directive.
Now you are ready to use the sign_in and sign_out methods on your controller tests:
sign_in @user, scope::admin
If you are testing Devise internal controllers or a controller that inherits from Devise's, you need to tell Devise which mapping should be used before a request. This is necessary because Devise gets this information from the router, but since controller tests do not pass through the router, it needs to be stated explicitly. For example, if you are testing the user scope, simply use:
test 'GET new'do# Mimic the router behavior of setting the Devise scope through the env.@request.env['devise.mapping'] =Devise.mappings[:user]
# Use the sign_in helper to sign in a fixture `User` record.
get :new# assert somethingend
Integration test helpers are available by including the Devise::Test::IntegrationHelpers module.
Devise allows you to set up as many Devise models as you want. If you want to have an Admin model with just authentication and timeout features, in addition to the User model above, just run:
# Create a migration with the required fields
create_table :adminsdo |t|
t.timestamps null:falseend# Inside your Admin model
devise :database_authenticatable, :timeoutable# Inside your routes
devise_for :admins# Inside your protected controller
before_action :authenticate_admin!# Inside your controllers and views
Alternatively, you can simply run the Devise generator.
Keep in mind that those models will have completely different routes. They do not and cannot share the same controller for sign in, sign out and so on. In case you want to have different roles sharing the same actions, we recommend that you use a role-based approach, by either providing a role column or using a dedicated gem for authorization.
If you are using Rails 4.2 and ActiveJob to deliver ActionMailer messages in the background through a queuing back-end, you can send Devise emails through your existing queue by overriding the send_devise_notification method in your model.
devise_mailer.send(notification, self, *args).deliver_later
Password reset tokens and Rails logs
If you enable the Recoverable module, note that a stolen password reset token could give an attacker access to your application. Devise takes effort to generate random, secure tokens, and stores only token digests in the database, never plaintext. However the default logging behavior in Rails can cause plaintext tokens to leak into log files:
Action Mailer logs the entire contents of all outgoing emails to the DEBUG level. Password reset tokens delivered to users in email will be leaked.
Active Job logs all arguments to every enqueued job at the INFO level. If you configure Devise to use deliver_laterto send password reset emails, password reset tokens will be leaked.
Rails sets the production logger level to DEBUG by default. Consider changing your production logger level to WARN if you wish to prevent tokens from being leaked into your logs. In config/environments/production.rb:
Devise supports ActiveRecord (default) and Mongoid. To select another ORM, simply require it in the initializer file.
Using Devise on Heroku with Ruby on Rails 3.2 requires setting: