How do I do a really simple Sinatra LDAP authentication? - ruby

Question

I looked at the Sinatra docs and they only seem to reference HTTP authentication. I'm looking for a really simple way to control access to routes based on a user being authorised/authenticated via an LDAP server.
I've already built a class that does the LDAP bit and returns an LDAP object if the user has successfully authenticated and nil if they haven't:
>>DirectoryUser.authenticate('user', 'password')
#<DirectoryUser:0x007ffb589a2328>
I can use this to determine if they've successfully authenticated or not.
As a next step I want to splice this into a simple Sinatra app that provides a form to collect the LDAP user and password:
require 'directoryUser'
require 'sinatra'
enable :sessions
get '/form' do
username = params[:username]
password = params[:password]
haml :form
end
Then I want to only allow routes if the 'DirectoryUser' object exists:
get '/protected' do # Only if DirectoryUser object exists
"This route is protected"
end
get '/unprotected' do
"This route is unprotected"
end
I've spent hours trying to find an answer to this but so far and can't seem to find anything that works for me.

Answer 1

I'd probably go with something like this:
require 'directoryUser'
require 'sinatra'
enable :sessions
helpers do
def authorize!
redirect(to('/login')) unless session[:user_id]
end
end
get '/login' do
haml :login # with the login form
end
post '/login' do
user = DirectoryUser.authenticate(params[:username], params[:password])
if user
session[:user_id] = user.id
# Or: session[:logged_in] = true, depending on your needs.
redirect to('/protected')
else
redirect to('/login')
end
end
get '/protected' do
authorize!
'This route is protected'
end
get '/unprotected' do
'This route is unprotected'
end