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Devise with Rails 6

Running devise with Rails 6


Checking Pre-requisites and Basic App Build

$ node -v
$ npm -v
$ ruby -v
ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-darwin17]
$ sqlite3 --version
3.19.3 2017-06-27 16:48:08 2b0954060fe10d6de6d479287dd88890f1bef6cc1beca11bc6cdb79f72e2377b
$ gem install rails
$ bundle config --local disable_platform_warnings true # to make dependency tzinfo-data warning go away
$ rails --version

Build a simple app with an Article model and controller:

$ rails new demo
$ cd demo
$ rails generate controller Welcome index
$ rails generate scaffold Article title:string text:text
$ rails db:migrate

some tidy up

$ cd demo
$ rm -fR .git # --skip-git would do this, but also means no .gitignore generated

Adding Devise

Add the devise gem to the Gemfile and bundle install

$ rails generate devise:install
$ rails generate devise:views
$ rails generate devise User

App Customization

Require authentication for the articles controller:

class ArticlesController < ApplicationController
  before_action :authenticate_user!

Add sign-in/out links in the application layout:

<%- unless 'Devise' %>
  <%- if user_signed_in? %>
    <%= link_to 'Log Out', destroy_user_session_path, method: :delete %><br />
  <% else %>
    <%= link_to 'Log In', new_user_session_path %><br />
  <% end %>
<% end %>

Devise Modules

Devise is a pluggable authentication system that uses warden under the cover for rack-based authentication.

Devise comes with 10 standard modules, 5 of which are enabled by default:

  • 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.
  • Recoverable: resets the user password and sends reset instructions.
  • Registerable: handles signing up users through a registration process, also allowing them to edit and destroy their account.
  • Rememberable: manages generating and clearing a token for remembering the user from a saved cookie.
  • Validatable: provides validations of email and password. It’s optional and can be customized, so you’re able to define your own validations.

The remaining 5 can be enabled as needed. Usually this just means updating the devise parameters in the user model, and checking module-specific items in the devise configuration file:

  • Omniauthable: adds OmniAuth support.
  • Confirmable: sends emails with confirmation instructions and verifies whether an account is already confirmed during sign in.
  • Trackable: tracks sign in count, timestamps and IP address.
  • Timeoutable: expires sessions that have not been active in a specified period of time.
  • Lockable: locks an account after a specified number of failed sign-in attempts. Can unlock via email or after a specified time period.

Third-party modules are available for other authentication requirements such as devise_invitable Devise modules are actually aquite easy to develop to suit specific requirements.


Root page (before sign-in)


Attempt to access articles will redirect to sign-in:


Managing articles after sign-in:


Credits and References

About LCK#145 rubyrailssecurity
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This page is a web-friendly rendering of my project notes shared in the LittleCodingKata GitHub repository.

LittleCodingKata is my collection of programming exercises, research and code toys broadly spanning things that relate to programming and software development (languages, frameworks and tools).

These range from the trivial to the complex and serious. Many are inspired by existing work and I'll note credits and references where applicable. The focus is quite scattered, as I variously work on things new and important in the moment, or go back to revisit things from the past.

This is primarily a personal collection for my own edification and learning, but anyone who stumbles by is welcome to borrow, steal or reference the work here. And if you spot errors or issues I'd really appreciate some feedback - create an issue, send me an email or even send a pull-request.