ruby - Sinatra clears session on post

Question

enable :sessions
set :session_secret, 'secret'

post '/login' do
        session[:loggedInUser] = jsondata['username'].to_s
        puts session[:loggedInUser] + " is the session"
end

Everything is good at this point. When I read the session like this:

get '/debug' do
    session.inspect
end

Its all there. But here comes the problem. When I go for another post request later on:

post '/foo' do
    # do nothing
end

The session is cleared.

Why? Is this a bug?

EDIT

I have narrowed the problem down: I proxypass Sinatra through nginx, to http://app.local/backend - this is when the issue occurs. If I run Sinatra through http://localhost:4567 it all works as expected.

SOLUTION

Use Rack::Session::Cookie instead of the default enable :sessions:

use Rack::Session::Cookie, :key => "rack.session",
:path => "/backend"
# etc

from the Sinatra FAQ:

If you need to set additional parameters for sessions, like expiration date, use Rack::Session::Cookie directly instead of enable :sessions:

Answer 1

I was suffering from the same issue as you: sessions were being cleared on post.

I have no idea why this works, but this is my solution:

#enable :sessions
use Rack::Session::Cookie, :key => 'rack.session',
                           :path => '/',
                           :secret => 'your_secret'

I literally just replaced the enable :sessions bit with use Rack::Session::Cookie ... and now all is good in the world.