Send messages to a global buffer in Ruby - ruby

Question

I know global variables aren't encouraged in Ruby but this is what I have been asked to do so you'll just have to go with me on this. I have a game that outputs messages to the command window successfully through the STDOUT. My task is to modify the class so that the messages are not only displayed to the STDOUT channel but also written to a buffer. This is so when I add an additional Sinatra method to the end of the file, the buffer is displayed in a browser (i.e localhost:4567).
So effectively, with the Sinatra gem called, running the spec.rb from a command window should result in the messages being displayed in the Web server in addition to the command window. But I do not know where to start in terms of outputting my messages to the buffer.
I'm pretty sure there is a very simple answer to this but my knowledge of ruby is not great. My thinking is I need to add a line to each activity concatenating the output of each to the global variable $buffer but how do I do this? Obviously following that, I need to write a Sinatra method that displays the contents of the global variable in the web browser.
Hope that makes sense.
I have two files, spec.rb and gen.rb. This is my code so far:
spec.rb
require "gen.rb"
module ImpossibleMachine
# Input and output constants processed by subprocesses
DOWN_ARROW = 1
UP_ARROW = 2
RIGHT_ARROW = 3
REPEAT_ARROW = 4
END_PROCESS = 5
START_CURRENT = 6
# RSpec Tests
describe Game do
describe "#start The impossible machine game" do
before(:each) do
#process = []
#output = double('output').as_null_object
#game = Game.new(#output)
end
it "sends a welcome message" do
#output.should_receive(:puts).with('Welcome to the Impossible Machine!')
#game.start
end
it "sends a starting message" do
#output.should_receive(:puts).with('Starting game...')
#game.start
end
it "should perform lifts_lever_turns_wheel activity which returns REPEAT_ARROW" do
#output.should_receive(:puts).with("Input: #{UP_ARROW}, Activity: Heave_ho_squeek_squeek")
#process[1] = #game.lifts_lever_turns_wheel(UP_ARROW)
#process[1].should == REPEAT_ARROW
end
it "should perform turns_tap_on_pulls_down_seesaw activity which returns DOWN_ARROW" do
#output.should_receive(:puts).with("Input: #{REPEAT_ARROW}, Activity: Drip_drip_creek_creek")
#process[2] = #game.turns_tap_on_pulls_down_seesaw(REPEAT_ARROW)
#process[2].should == DOWN_ARROW
end
it "should perform pulls_down_seezaw_starts_current activity which returns START_CURRENT" do
#output.should_receive(:puts).with("Input: #{DOWN_ARROW}, Activity: Creek_creek_buzz_buzz")
#process[2] = #game.pulls_down_seezaw_starts_current(DOWN_ARROW)
#process[2].should == START_CURRENT
end
it "should perform starts_current_pushes_grove activity which returns RIGHT_ARROW" do
#output.should_receive(:puts).with("Input: #{START_CURRENT}, Activity: Buzz_buzz_pow_wallop")
#process[3] = #game.starts_current_pushes_grove(START_CURRENT)
#process[3].should == RIGHT_ARROW
end
it "sends a finishing message" do
#output.should_receive(:puts).with('...Game finished.')
#game.finish
end
end
end
end
gen.rb
require 'sinatra'
$buffer = ""
# Main class module
module ImpossibleMachine
# Input and output constants processed by subprocesses. MUST NOT change.
DOWN_ARROW = 1
UP_ARROW = 2
RIGHT_ARROW = 3
REPEAT_ARROW = 4
END_PROCESS = 5
START_CURRENT = 6
class Game
attr_reader :process, :output
attr_writer :process, :output
def initialize(output)
#output = output
puts "[#{#output}]"
end
# All the code/methods aimed at passing the RSpect tests are below.
def start
#output.puts'Welcome to the Impossible Machine!'
#output.puts'Starting game...'
end
def lifts_lever_turns_wheel(input)
#input = input
#output.puts 'Input: 2, Activity: Heave_ho_squeek_squeek'
return REPEAT_ARROW
end
def turns_tap_on_pulls_down_seesaw(input)
#input = input
#output.puts 'Input: 4, Activity: Drip_drip_creek_creek'
return DOWN_ARROW
end
def pulls_down_seezaw_starts_current(input)
#input = input
#output.puts 'Input: 1, Activity: Creek_creek_buzz_buzz'
return START_CURRENT
end
def starts_current_pushes_grove(input)
#input = input
#output.puts 'Input: 6, Activity: Buzz_buzz_pow_wallop'
return RIGHT_ARROW
end
def finish
#output.puts'...Game finished.'
end
end
end
# Main program
module ImpossibleMachine
#process = []
g = Game.new(STDOUT)
# All code added to output the activity messages to the command line window is below.
g.start
#process[0] = g.lifts_lever_turns_wheel(2)
#process[1] = g.turns_tap_on_pulls_down_seesaw(#process[0])
#process[2] = g.pulls_down_seezaw_starts_current(#process[1])
#process[3] = g.starts_current_pushes_grove(#process[2])
g.finish
end
# Any sinatra code added to output the activity messages to a browser should be added below.
# End program

Answer 1

managed to get this to work after hours!
At the top add/adjust to:
require 'stringio'
$buffer= StringIO.new
in the main program:
g = Game.new($buffer)
g.start
#process[0] = g.lifts_lever_turns_wheel(2)
etc......
g.finish
puts $buffer.string #this sends it to stdout
then just add in the sinatra coding at the bottom which will also use $buffer.string
possibly not the best or smartest way to do it but it uses the global buffer they wanted and gets it to sinatra and the cmd line.

Answer 2

I think you could just create some sort of buffer object in your main program and pass it in the game, just like you pass in STDOUT. Then you could call write methods on the passed in object inside the game.