undefined local variable or method `res' for main:Object (NameError) - ruby

Question

I have the following little script that connects to a host, and gets some output.
#!/usr/bin/env ruby
require 'net/http'
require 'net/https'
require 'timeout'
serverurl = "http://www.google.com/"
uri = URI(serverurl)
res = Net::HTTP.post_form(uri, 'method' => 'login', 'username' => 'admin', 'password' => 'MySup3rDup3rp#55w0rd')
cookie = res['set-cookie']
if cookie.nil?
puts "No cookie"
end
I want to use some timeout so I do:
#!/usr/bin/env ruby
require 'net/http'
require 'net/https'
require 'timeout'
serverurl = "http://www.google.com/"
uri = URI(serverurl)
begin
timeout(10) do
res = Net::HTTP.post_form(uri, 'method' => 'login', 'username' => 'admin', 'password' => 'MySup3rDup3rp#55w0rd')
end
rescue StandardError,Timeout::Error
puts "#{server} Timeout"
exit(1)
end
cookie = res['set-cookie']
if cookie.nil?
puts "No cookie"
end
Now I get some error:
test.rb:20:in `<main>': undefined local variable or method `res' for main:Object (NameError)
I don't know why, because a similar test code works without error:
require "timeout"
begin
timeout(6) do
sleep
end
#rescue # under ruby >= 1.9 is ok
rescue StandardError,Timeout::Error # workaround for ruby < 1.9
p "I'm sorry, Sir. We couldn't make it, Sir."
end
Any idea what am I doing wrong?

Answer 1

This is about scope. In Ruby, variables are only visible within the same scope where they are defined (exceptions are instance-, class-, and global variables as well as constants).
So in your example, res is only visible within the timeout-block. Add res = nil before the begin-block to make sure res is defined in the scope you actually need the value.