sinatra session auth example (without database)

session-auth-sinatra-app.rb

require 'sinatra'

enable :sessions

# helpers/session_helper.rb
helpers do
  def session_user_id
    session[:user_id]
  end

  def session_logout
    session.delete :user_id
  end

  def session_login(user_id)
    session[:user_id] = user_id
  end
end

# controllers/home.rb
get '/' do
  if session_user_id
    "HELLO USER #{session_user_id}" + '<a href="/logout">logout</a>'
  else
    'Please <a href="/login">login</a>'
  end
end

# controllers/session.rb

# POST /session/new
# POST /login
# Should really be a POST 
get '/login' do
  session_login(55) # you would get this from the user authentication
  redirect '/'
end

# DELETE /session
get '/logout' do
  session_logout
  redirect '/'
end