def handshake
unless key = request['sec-websocket-key']
raise HandshakeError, "Sec-WebSocket-Key header is required"
end
origin = request['sec-websocket-origin']
protocols = request['sec-websocket-protocol']
extensions = request['sec-websocket-extensions']
string_to_sign = "#{key}258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
signature = Base64.encode64(Digest::SHA1.digest(string_to_sign)).chomp
upgrade = ["HTTP/1.1 101 Switching Protocols"]
upgrade << "Upgrade: websocket"
upgrade << "Connection: Upgrade"
upgrade << "Sec-WebSocket-Accept: #{signature}"
debug [:upgrade_headers, upgrade]
return upgrade.join("\r\n") + "\r\n\r\n"
end