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https://github.com/mikker/passwordless

🗝 Authentication for your Rails app without the icky-ness of passwords
https://github.com/mikker/passwordless

authentication engine passwordless rails ruby

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🗝 Authentication for your Rails app without the icky-ness of passwords

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README 

        


  Passwordless

  


  





[![CI](https://github.com/mikker/passwordless/actions/workflows/ci.yml/badge.svg)](https://github.com/mikker/passwordless/actions/workflows/ci.yml) [![Rubygems](https://img.shields.io/gem/v/passwordless.svg)](https://rubygems.org/gems/passwordless) [![codecov](https://codecov.io/gh/mikker/passwordless/branch/master/graph/badge.svg)](https://codecov.io/gh/mikker/passwordless)



Add authentication to your Rails app without all the icky-ness of passwords. _Magic link_ authentication, if you will. We call it _passwordless_.



- [Installation](#installation)

  - [Upgrading](#upgrading)

- [Usage](#usage)

  - [Getting the current user, restricting access, the usual](#getting-the-current-user-restricting-access-the-usual)

  - [Providing your own templates](#providing-your-own-templates)

  - [Registering new users](#registering-new-users)

  - [URLs and links](#urls-and-links)

  - [Route constraints](#route-constraints)

- [Configuration](#configuration)

  - [Delivery method](#delivery-method)

  - [Token generation](#token-generation)

  - [Timeout and Expiry](#timeout-and-expiry)

  - [Redirection after sign-in](#redirection-after-sign-in)

  - [Looking up the user](#looking-up-the-user)

- [Test helpers](#test-helpers)

- [Security considerations](#security-considerations)

- [Alternatives](#alternatives)

- [License](#license)



## Installation



Add to your bundle and copy over the migrations:



```sh

$ bundle add passwordless

$ bin/rails passwordless_engine:install:migrations

```



### Upgrading



See [Upgrading to Passwordless 1.0](docs/upgrading_to_1_0.md) for more details.



## Usage



Passwordless creates a single model called `Passwordless::Session`, so it doesn't come with its own user model. Instead, it expects you to provide one, with an email field in place. If you don't yet have a user model, check out the wiki on [creating the user model](https://github.com/mikker/passwordless/wiki/Creating-the-user-model).



Enable Passwordless on your user model by pointing it to the email field:



```ruby

class User < ApplicationRecord

  # your other code..



  passwordless_with :email # <-- here! this needs to be a column in `users` table



  # more of your code..

end

```



Then mount the engine in your routes:



```ruby

Rails.application.routes.draw do

  passwordless_for :users



  # other routes

end

```



### Getting the current user, restricting access, the usual



Passwordless doesn't give you `current_user` automatically. Here's how you could add it:



```ruby

class ApplicationController < ActionController::Base

  include Passwordless::ControllerHelpers # <-- This!



  # ...



  helper_method :current_user



  private



  def current_user

    @current_user ||= authenticate_by_session(User)

  end



  def require_user!

    return if current_user

    save_passwordless_redirect_location!(User) # <-- optional, see below

    redirect_to root_path, alert: "You are not worthy!"

  end

end

```



Et voilà:



```ruby

class VerySecretThingsController < ApplicationController

  before_action :require_user!



  def index

    @things = current_user.very_secret_things

  end

end

```



### Providing your own templates



To make Passwordless look like your app, override the bundled views by adding your own. You can manually copy the specific views that you need or copy them to your application with `rails generate passwordless:views`.



Passwordless has 2 action views and 1 mailer view:



```sh

# the form where the user inputs their email address

app/views/passwordless/sessions/new.html.erb

# the form where the user inputs their just received token

app/views/passwordless/sessions/show.html.erb

# the email with the token and magic link

app/views/passwordless/mailer/sign_in.text.erb

```



See [the bundled views](https://github.com/mikker/passwordless/tree/master/app/views/passwordless).



### Registering new users



Because your `User` record is like any other record, you create one like you normally would. Passwordless provides a helper method to sign in the created user after it is saved – like so:



```ruby

class UsersController < ApplicationController

  include Passwordless::ControllerHelpers # <-- This!

  # (unless you already have it in your ApplicationController)



  def create

    @user = User.new(user_params)



    if @user.save

      sign_in(create_passwordless_session(@user)) # <-- This!

      redirect_to(@user, flash: { notice: 'Welcome!' })

    else

      render(:new)

    end

  end



  # ...

end

```



### URLs and links



By default, Passwordless uses the resource name given to `passwordless_for` to generate its routes and helpers.



```ruby

passwordless_for :users

  # <%= users_sign_in_path %> # => /users/sign_in



passwordless_for :users, at: '/', as: :auth

  # <%= auth_sign_in_path %> # => /sign_in

```



Also be sure to

[specify ActionMailer's `default_url_options.host`](http://guides.rubyonrails.org/action_mailer_basics.html#generating-urls-in-action-mailer-views) and tell the routes as well:



```ruby

# config/application.rb for example:

config.action_mailer.default_url_options = {host: "www.example.com"}

routes.default_url_options[:host] ||= "www.example.com"

```



Note as well that `passwordless_for` accepts a custom controller. One possible application of this

is to add a `before_action` that redirects authenticated users from the sign-in routes, as in this example:



```ruby

# config/routes.rb

passwordless_for :users, controller: "sessions"

```



```ruby

# app/controllers/sessions_controller.rb



class SessionsController < Passwordless::SessionsController

  before_action :require_unauth!, only: %i[new show]



  private



  def require_unauth!

    return unless current_user

    redirect_to("/", notice: "You are already signed in.")

  end

end

```



### Route constraints



With [constraints](https://guides.rubyonrails.org/routing.html#request-based-constraints) you can restrict access to certain routes.

Passwordless provides `Passwordless::Constraint` and it's negative counterpart `Passwordless::ConstraintNot` for this purpose.



To limit a route to only authenticated `User`s:



```ruby

constraints Passwordless::Constraint.new(User) do

  # ...

end

```



The constraint takes a second `if:` argument, that expects a block and is passed the `authenticatable` record, (ie. `User`):



```ruby

constraints Passwordless::Constraint.new(User, if: -> (user) { user.email.include?("john") }) do

  # ...

end

```



The negated version has the same API but with the opposite result, ie. ensuring authenticated user **don't** have access:



```ruby

constraints Passwordless::ConstraintNot.new(User) do

  get("/no-users-allowed", to: "secrets#index")

end

```



## Configuration



To customize Passwordless, create a file `config/initializers/passwordless.rb`.



The default values are shown below. It's recommended to only include the ones that you specifically want to modify.



```ruby

Passwordless.configure do |config|

  config.default_from_address = "[email protected]"

  config.parent_controller = "ApplicationController"

  config.parent_mailer = "ActionMailer::Base"

  config.restrict_token_reuse = true # Can a token/link be used multiple times?

  config.token_generator = Passwordless::ShortTokenGenerator.new # Used to generate magic link tokens.



  config.expires_at = lambda { 1.year.from_now } # How long until a signed in session expires.

  config.timeout_at = lambda { 10.minutes.from_now } # How long until a token/magic link times out.



  config.redirect_back_after_sign_in = true # When enabled the user will be redirected to their previous page, or a page specified by the `destination_path` query parameter, if available.

  config.redirect_to_response_options = {} # Additional options for redirects.

  config.success_redirect_path = '/' # After a user successfully signs in

  config.failure_redirect_path = '/' # After a sign in fails

  config.sign_out_redirect_path = '/' # After a user signs out



  config.paranoid = false # Display email sent notice even when the resource is not found.



  config.after_session_confirm = ->(request, session) {} # Called after a session is confirmed.

end

```



### Delivery method



By default, Passwordless sends emails. See [Providing your own templates](#providing-your-own-templates). If you need to customize this further, you can do so in the `after_session_save` callback.



In `config/initializers/passwordless.rb`:



```ruby

Passwordless.configure do |config|

  config.after_session_save = lambda do |session, request|

    # Default behavior is

    # Passwordless::Mailer.sign_in(session).deliver_now



    # You can change behavior to do something with session model. For example,

    # SmsApi.send_sms(session.authenticatable.phone_number, session.token)

  end

end

```



## After Session Confirm Hook



An `after_session_confirm` hook is called after a successful session confirmation – in other words: after a user signs in successfully.



```ruby

Passwordless.configure do |config|

  config.after_session_confirm = ->(session, request) {

    user = session.authenticatable

    user.update!(

      email_verified: true.

      last_login_ip: request.remote_ip

    )

  }

end

### Token generation



By default Passwordless generates short, 6-digit, alpha numeric tokens. You can change the generator using `Passwordless.config.token_generator` to something else that responds to `call(session)` eg.:



```ruby

Passwordless.configure do |config|

  config.token_generator = lambda do |session|

    "probably-stupid-token-#{session.user_agent}-#{Time.current}"

  end

end

```



Passwordless will keep generating tokens until it finds one that hasn't been used yet. So be sure to use some kind of method where matches are unlikely.



### Timeout and Expiry



The _timeout_ is the time by which the generated token and magic link is invalidated. After this the token cannot be used to sign in to your app and the user will need to request a new token.



The _expiry_ is the expiration time of the session of a logged in user. Once this is expired, the user is signed out.



**Note:** Passwordless' session relies on Rails' own session and so will never live longer than that.



To configure your Rails session, in `config/initializers/session_store.rb`:



```ruby

Rails.application.config.session_store :cookie_store,

  expire_after: 1.year,

  # ...

```



### Redirection after sign-in



By default Passwordless will redirect back to where the user wanted to go _if_ it knows where that is -- so you'll have to help it. `Passwordless::ControllerHelpers` provide a method:



```ruby

class ApplicationController < ActionController::Base

  include Passwordless::ControllerHelpers # <-- Probably already have this!



  # ...



  def require_user!

    return if current_user

    save_passwordless_redirect_location!(User) # <-- this one!

    redirect_to root_path, alert: "You are not worthy!"

  end

end

```



This can also be turned off with `Passwordless.config.redirect_back_after_sign_in = false`.



### Looking up the user



By default Passwordless uses the `passwordless_with` column to _case insensitively_ fetch the user resource.



You can override this by defining a class method `fetch_resource_for_passwordless` in your user model. This method will be called with the down-cased, stripped `email` and should return an `ActiveRecord` instance.



```ruby

class User < ApplicationRecord

  def self.fetch_resource_for_passwordless(email)

    find_or_create_by(email: email)

  end

end

```



## Test helpers



To help with testing, a set of test helpers are provided.



If you are using RSpec, add the following line to your `spec/rails_helper.rb`:



```ruby

require "passwordless/test_helpers"

```



If you are using TestUnit, add this line to your `test/test_helper.rb`:



```ruby

require "passwordless/test_helpers"

```



Then in your controller, request, and system tests/specs, you can utilize the following methods:



```ruby

passwordless_sign_in(user) # signs you in as a user

passwordless_sign_out # signs out user

```



## Security considerations



There's no reason that this approach should be less secure than the usual username/password combo. In fact this is most often a more secure option, as users don't get to choose the horrible passwords they can't seem to stop using. In a way, this is just the same as having each user go through "Forgot password" on every login.



But be aware that when everyone authenticates via emails, the way you send those mails becomes a weak spot. Email services usually provide a log of all the mails you send so if your email delivery provider account is compromised, every user in the system is as well. (This is the same for "Forgot password".) [Reddit was once compromised](https://thenextweb.com/hardfork/2018/01/05/reddit-bitcoin-cash-stolen-hack/) using this method.



Ideally you should set up your email provider to not log these mails. And be sure to turn on non-SMS 2-factor authentication if your provider supports it.



## Alternatives



- [OTP JWT](https://github.com/stas/otp-jwt) -- Passwordless JSON Web Tokens



## License



MIT