Question

Is there a way to scope variables to the thread without having to pass everything around, given a class with the following methods:

  def initialize
    @server = TCPServer.new('localhost',456)
  end

  def start
    threads = []
    while (upload = @server.accept)
      threads << Thread.new(upload) do |connection|
         some_method_here(connection)
      end
    end
    threads.each {|t| t.join }
  end

  def some_method_here(connection)
     variable = "abc"
     another_method(connection,variable)
  end

  def another_method(connection,variable)
      puts variable.inspect
      connection.close
  end

Answer 1

if I get you right you want to use thread local variables (see the ruby rdoc for Thread#[])

From the rdoc:

   a = Thread.new { Thread.current["name"] = "A"; Thread.stop }
   b = Thread.new { Thread.current[:name]  = "B"; Thread.stop }
   c = Thread.new { Thread.current["name"] = "C"; Thread.stop }
   Thread.list.each {|x| puts "#{x.inspect}: #{x[:name]}" }

produces:

   #<Thread:0x401b3b3c sleep>: C
   #<Thread:0x401b3bc8 sleep>: B
   #<Thread:0x401b3c68 sleep>: A
   #<Thread:0x401bdf4c run>:

So your example would use

Thread.current[:variable] = "abc"
Thread.current[:variable] # => "abc"

wherever you were using just variable before