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Tachiban (立ち番 - standing watch) provides simple authentication system for Hanami web applications by using bcrypt for password hashing and offers the following functionalities (with methods listed below under Methods by features):

  • Signup
  • Login
  • Authentication
  • Session handling
  • Password reset
  • Authorization

The Tachiban logic (apart from the Authorization) and code were extracted from a Hanami based web app using Hanami::Model and was also used in a Camping based web app using Active Record.


Add this line to your application's Gemfile:

gem 'tachiban'

And then execute:

$ bundle

Or install it yourself as:

$ gem install tachiban

Tachiban is already setup to be included by your Hanami application:

::Hanami::Controller.configure do
  prepare do
    include Hanami::Tachiban



Prior to logging in or authenticating the user, retrieve the entity from the database and assign it to the instance variable of @user.

The password reset methods require the user entity to have the following attributes: token and password_reset_sent_at (set as Time.now). The token can be used to compose the password reset url and to later retrieve the correct user from the database when the user visits the password reset url.

The password_reset_sent_at can be used to check the reset link validity.

The only prerequisite for the authorization is the attribute of role for the user entity.



The entity for which authentication is used must have the attribute hashed_pass to hold the generated hashed password.

To create a user with a hashed password use the hashed_password(password) method for the password and store it as the user's attribute hashed_pass.


# Create action for an entity
def call(params)
  password = params[:newuser][:password]
  hashed_pass = hashed_password(password)
  repository = UserRepository.new

  @user = repository.create(name: name, surname: surname, email: email,
  hashed_pass: hashed_pass))


To authenticate a user use the authenticated?(input_password) method and log them in with the login method. Authentication is successful if the user exists and passwords match.

The user is logged in by setting the user object as the session[:current_user]. After the user is logged in the session start time is defined as session[:session_start_time] = Time.now. A flash message is also assigned as flash[:success_notice] = flash_message.

The session[:session_start_time] is then used by the session_expired? method to determine whether the session has expired or not.

Example of session creation for an entity

# Create action for an entity session
email = params[:entity_session][:email]
password = params[:entity_session][:password]

@user = EntityRepository.new.find_by_email(email)
("You have been successfully logged in.") if authenticated?(password)


To check whether the user is logged in use the check_for_logged_in_user method. If the user is not logged in the logout method takes over.

Session handling

Tachiban handles session expiration by checking if a session has expired and then restarts the session start time if the session is still valid or proceeds with the following if the session has expired:

  • setting the session[:current_user] to nil
  • a flash message is set: flash[:failed_notice] = "Your session has expired"
  • redirects to the routes.root_path which can be overwritten by assigning a different url to @redirect_url

The session_expired? method compares the session start time increased for the defined @validity_time (set to 10 minutes by default, but can be overwritten) with the current time.

handle_session method:

  def handle_session
    if session_expired?
      @redirect_url ||= routes.root_path
      session[:current_user] = nil
      flash[:failed_notice] = "Your session has expired"
      redirect_to @redirect_url

Example of session handling in a share code module

module Web
  module HandleSession

     def self.included(action)
       action.class_eval do
         before :handle_session


Password reset

The password reset feature provides a few simple methods to generate a token, email subject and body. It is also possible to specify and check the validity of the password reset url.

token # => "YbRucc8YUlFJrYYp04eQKQ"
email_subject(SomeApp) # => "SomeApp -- password reset request"

Provide the base url, the token and the number and type of the time units for the validity of the link.

body = email_body(base_url, url_token, 2, "hour")
# => "Visit this url to reset your password: http://localhost:2300/passwordupdate/asdasdasdaerwrw.
#     The url will be valid for 2 hour(s).")

The link validity must me specified in seconds. The method compares the current time with the time when the password reset link was sent increased by the link validity: Time.now > @user.password_reset_sent_at + link_validity



Authorization support was setup as inspired by this blog post.

Authorization features support the generation of policy files for each controller where authorized roles are specified for each action.

tachiban -n mightyPoster -p post

The above CLI command will generate a policy file for the application mightyPoster (not the project) and the controller post. The file will be generated as myProject/lib/mightyPoster/policies/PostPolicy.rb

Each application would have its own app/policies folders.

The command must be run in the project root folder.

Once the file is generated the authorized roles variables in the initialize block for required actions need to be uncommneted and supplied with specific roles.

Then we can check if a user is authorized:

authorized?(controller, role, action)


  • Add support for level based authorizations. [x]
  • Add generators for adding authorization rules to existing policies.
  • Add generators for entities with required attributes.



Method: Tachiban::login
Change: session[:current_user] is not set as the user object, but as the user object id.

Method: Tachiban::logout
Change: Added session.clear to remove any other values upon logout.


After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.


Bug reports and pull requests are welcome on GitHub at https://github.com/sebastjan-hribar/tachiban. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.


The gem is available as open source under the terms of the MIT License.