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module AuthenticatedSystem
SESSION_MAX_AGE = 7.days
ELEVATION_MAX_AGE = 30.minutes
MAX_ELEVATION_EXTENSIONS = 3
protected
# Returns true or false if the user is logged in.
# Preloads @current_user with the user model if they're logged in.
def logged_in?
!!current_user
end
# Accesses the current user from the session.
# Future calls avoid the database because nil is not equal to false.
def current_user
@current_user ||= login_from_session unless @current_user == false
end
# Store the given user id in the session.
def current_user=(new_user)
session[:user_id] = new_user ? new_user.id : nil
@current_user = new_user || false
end
# Tied to is_admin? so losing the role closes the window at once, rather
# than leaving a timestamp that would count again if the role returned.
def elevated?
return false unless current_user&.is_admin?
return false unless current_user.otp_enrolled?
session[:elevated_at].to_i > ELEVATION_MAX_AGE.ago.to_i
end
def elevation_expires_at
return nil unless elevated?
Time.at(session[:elevated_at].to_i) + ELEVATION_MAX_AGE
end
def elevate!
session[:elevated_at] = Time.now.to_i
session[:elevation_extensions] = 0
end
def elevation_extensions_left
return 0 unless elevated?
MAX_ELEVATION_EXTENSIONS - session[:elevation_extensions].to_i
end
def renew_elevation!
return false unless elevated?
return false unless elevation_extensions_left > 0
session[:elevation_extensions] = session[:elevation_extensions].to_i + 1
session[:elevated_at] = Time.now.to_i
true
end
def drop_elevation!
session.delete(:elevated_at)
session.delete(:elevation_extensions)
end
# Check if the user is authorized
#
# Override this method in your controllers if you want to restrict access
# to only a few actions or if you want to check if the user
# has the correct rights.
#
# Example:
#
# # only allow nonbobs
# def authorized?
# current_user.login != "bob"
# end
#
def authorized?(action = action_name, resource = nil)
logged_in?
end
# Filter method to enforce a login requirement.
#
# To require logins for all actions, use this in your controllers:
#
# before_filter :login_required
#
# To require logins for specific actions, use this in your controllers:
#
# before_filter :login_required, :only => [ :edit, :update ]
#
# To skip this in a subclassed controller:
#
# skip_before_filter :login_required
#
def login_required
authorized? || access_denied
end
# Redirect as appropriate when an access request fails.
#
# The default action is to redirect to the login screen.
#
# Override this method in your controllers if you want to have special
# behavior in case the user is not authorized
# to access the requested action. For example, a popup window might
# simply close itself.
def access_denied
respond_to do |format|
format.html do
store_location
redirect_to new_session_path
end
end
end
# Store the URI of the current request in the session.
#
# We can return to this location by calling #redirect_back_or_default.
def store_location
session[:return_to] = request.fullpath
end
# Redirect to the URI stored by the most recent store_location call or
# to the passed default. Set an appropriately modified
# after_filter :store_location, :only => [:index, :new, :show, :edit]
# for any controller you want to be bounce-backable.
def redirect_back_or_default(default)
redirect_to(session[:return_to] || default)
session[:return_to] = nil
end
# Inclusion hook to make #current_user and #logged_in?
# available as ActionView helper methods.
def self.included(base)
base.send :helper_method, :current_user, :logged_in?, :authorized?,
:elevated?, :elevation_expires_at, :elevation_extensions_left if base.respond_to? :helper_method
end
#
# Login
#
# Called from #current_user. First attempt to login by the user id stored in the session.
def login_from_session
return unless session[:user_id]
if session[:logged_in_at].to_i > SESSION_MAX_AGE.ago.to_i
user = User.find_by(:id => session[:user_id])
if user.nil? || user.alumni?
session[:user_id] = nil
else
self.current_user = user
end
else
session[:user_id] = nil
end
end
#
# Logout
#
# This is ususally what you want; resetting the session willy-nilly wreaks
# havoc with forgery protection, and is only strictly necessary on login.
# However, **all session state variables should be unset here**.
def logout_keeping_session!
@current_user = false # not logged in, and don't do it for me
session[:user_id] = nil # keeps the session but kill our variable
session.delete(:elevated_at)
session.delete(:elevation_attempts)
session.delete(:elevation_extensions)
end
# The session should only be reset at the tail end of a form POST --
# otherwise the request forgery protection fails. It's only really necessary
# when you cross quarantine (logged-out to logged-in).
def logout_killing_session!
logout_keeping_session!
reset_session
end
end
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