How to use sinatra session

Question

enable :sessions
get '/foo' do
  session['m'] = 'Hello World!'
  redirect '/bar'
end

get '/bar' do
  session['m']   # => 'Hello World!'

end

It does not seem to work.

Answer 1

Are you using shotgun? If so, do the following:

configure(:development) { set :session_secret, "something" }

This will no longer be necessary in Sinatra 1.3.

Answer 2

Perhaps you have cookies disabled on your web browser? Sinatra's sessions use cookies by default.

Here's my test app:

require 'sinatra'
enable :sessions
get '/foo' do
  session['m'] = 'Hello World!'
  redirect '/bar'
end
get '/bar' do
  <<-ENDRESPONSE
    Ruby:    #{RUBY_VERSION}
    Rack:    #{Rack::VERSION}
    Sinatra: #{Sinatra::VERSION}
    #{session['m'].inspect}
  ENDRESPONSE
end

And here it is in action:

phrogz$ curl --cookie-jar cookies.txt -L http://localhost:4567/foo
    Ruby:    1.9.2
    Rack:    [1, 1]
    Sinatra: 1.2.3
    "Hello World!"

phrogz$ curl -L http://localhost:4567/foo
    Ruby:    1.9.2
    Rack:    [1, 1]
    Sinatra: 1.2.3
    nil

phrogz$ cat cookies.txt 
# Netscape HTTP Cookie File
# http://curl.haxx.se/rfc/cookie_spec.html
# This file was generated by libcurl! Edit at your own risk.

localhost   FALSE   /   FALSE   0   rack.session    BAh7BkkiBm0GOgZFRkkiEUhl...

Without cookies, your redirect will work but it will be as though it's a brand new session after the redirect, with the session starting from scratch.