FS_Server

privChan = 31000 + os.getComputerID()
pubChan = 31000
continue = false
modemFound = peripheral.find("modem")
if modemFound then
    modem = modemFound
    modem.open(privChan)
    modem.open(pubChan)
    continue = true
end
while continue do
    e = {os.pullEvent("modem_message")}
    msg = textutils.unserialize(e[5])
    chan = e[3]
    if chan == pubChan then
        cmd = msg[1]
        args = msg[2]
        if cmd == "Find" then
            if fs.exists(args) then
                modem.transmit(e[4],privChan, textutils.serialize({"success","File found"}))
            end
        elseif cmd == "getFreeSpace" then
            freeSpace = fs.getFreeSpace("/")
            modem.transmit(e[4],privChan, textutils.serialize({"success",freeSpace}))
        end
    elseif chan == privChan then
        cmd = msg[1]
        args = msg[2]
        if cmd == "Request" then
            if fs.exists(args) then
                f = fs.open(args,"r")
                modem.transmit(e[4],privChan, f.readAll())
                f.close()
            else
                modem.transmit(e[4],privChan,textutils.serialize({"error","File not found"}))
            end
        elseif cmd == "SaveFile" then
            f = fs.open(args,"w")
            f.write(msg[3])
            f.close()
            modem.transmit(e[4],privChan, textutils.serialize({"success","File saved"}))
        end
    end
end