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require 'open3'
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class PortInUse < StandardError; end
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class VNCProxy
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attr_accessor :host, :host_port, :password, :timeout
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attr_reader :proxy_port
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# Allowed ports to communicate with our web sockets proxy
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PORTS = 5910..5930
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def initialize(attributes)
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# setup all attributes.
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defaults.merge(attributes).each do |k, v|
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eval("self.#{k}= v") if self.respond_to?("#{k}=")
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end
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end
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def self.start attributes
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proxy = VNCProxy.new(attributes)
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proxy.start_proxy
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end
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def start_proxy
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# try to execute our web sockets proxy
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port = PORTS.first
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begin
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cmd = "#{ws_proxy} --daemon --run-once --timeout=#{timeout} #{port} #{host}:#{host_port}"
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execute(cmd)
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# if the port is already in use, try another one from the pool
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# this is not ideal, as it would try all ports in order
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# but it avoids any threading issues etc.
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# TODO: try to select a port from a pool randomly, so we always hit all active connections.
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rescue PortInUse
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port += 1
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retry if port <= PORTS.last
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end
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@proxy_port = port
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{ :host => host, :port => host_port, :password => password, :proxy_port => proxy_port }
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end
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private
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def ws_proxy
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"#{Rails.root}/extras/noVNC/wsproxy.py"
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end
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def defaults
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{
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:timeout => 120,
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:host_port => 5900,
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:host => "0.0.0.0",
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}
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end
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def logger
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Rails.logger
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end
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def execute cmd
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logger.debug "Starting VNC Proxy: #{cmd}"
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Open3::popen3(cmd) do |stdin, stdout, stderr|
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stdout.each do |line|
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logger.debug "[#{line}"
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end
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stderr.each do |line|
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logger.debug "VNCProxy Error: #{line}"
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raise PortInUse if line["socket.error: [Errno 98] Address already in use"]
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end
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end
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end
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end
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