database.lua

local component = require("component")
local tcpnet = require("tcpnet")
local event = require("event")
local s = require("serialization")
portkeepalive = 255
portopen = 1026
portrequest = 1027
handle = tcpnet.new("198.27.109.102")
handle:open(portopen)
handle:open(portrequest)
handle:open(portkeepalive)
stationradar = {}
ottawaradar = {}
shipradar = {}


function keepalive()
        event.ignore("tcpnet_message", sendinformation)
        handle:send(portkeepalive, "ping")
        print("haven't been pinged in a while, pinging")
        local _, _, port, data = event.pull(10, "tcpnet_message")
            if data == nil then
                print("got nothing, reconnecting")
                handle:close(portopen)
                handle:close(portrequest)
                handle:close(portkeepalive)
                handle = tcpnet.new("198.27.109.102")
                handle:open(portopen)
                handle:open(portrequest)
                handle:open(portkeepalive)
                a = event.timer(30, keepalive)
                event.listen("tcpnet_message", incoming)
                return
            elseif port == portkeepalive and data == "pong" then
                print("got keep alive")
                a = event.timer(30, keepalive)
                event.listen("tcpnet_message", incoming)
                return
            end
end



function incoming(_, _, port, data)
        if port == portopen then
            if string.find(data, "stationradar") then
                print("saving stationradar as radar")
                data = string.gsub(data, "stationradar", "radar")
                stationradar = s.unserialize(data)
                event.cancel(a)
                a = event.timer(30, keepalive)
            elseif string.find(data, "ottawaradar") then
                print("saving ottawaradar as radar")
               data = string.gsub(data, "ottawaradar", "radar")
                ottawaradar = s.unserialize(data)
                event.cancel(a)
                a = event.timer(30, keepalive)
            elseif string.find(data, "shipradar") then
                print("saving shipradar as radar")
               data = string.gsub(data, "shipradar", "radar")
                shipradar = s.unserialize(data)
                event.cancel(a)
                a = event.timer(30, keepalive)
            end
        elseif port == portrequest then
            if string.find(data, "request") then
                if string.find(data, "station") then
                print("got request for station variable")
                handle:send(portrequest, s.serialize(stationradar))
                event.cancel(a)
                a = event.timer(30, keepalive)
                elseif string.find(data, "ottawa") then
                print("got request for ottawa variable")
                handle:send(portrequest, s.serialize(ottawaradar))
                event.cancel(a)
                a = event.timer(30, keepalive)
                elseif string.find(data, "ship") then
                print("got request for ship variable")
                handle:send(portrequest, s.serialize(shipradar))
                event.cancel(a)
                a = event.timer(30, keepalive)
                end
            end
        end
end
print("register TCPnet listen")
event.listen("tcpnet_message", incoming)
print("register keepalive timer")
a = event.timer(30, keepalive)
while true do
event.pull()
os.sleep(0)
end