Chat Server

chatserver.lua

-- Chat Server by CoderPuppy

local protocol = 'cpup/chat'

local tArgs = { ... }

local function printUsage()
	print('Usages:')
	print('chatserver.lua <hostname>')
end

local function openModem()
	local modemFound = false
	for i, side in ipairs(peripheral.getNames()) do
		if peripheral.getType(side) == 'modem' then
			if not rednet.isOpen(side) then
				rednet.open(side)
			end
			modemFound = true
		end
	end
	if not modemFound then
		print('No modems found.')
	end
	return modemFound
end

-- 'chat host'
-- Get hostname
local hostname = tArgs[1]
if hostname == nil then
	printUsage()
	return
end

-- Host server
if not openModem() then
	return
end
rednet.host(protocol, hostname)
print('0 users connected.')

local users = {}
local nUsers = 0
function send(msgType, msg, userID)
	if userID then
		local user = users[userID]
		if user then
			-- print('sending ' .. msgType .. ' to ' .. user.username)
			-- print('sending: ' .. textutils.serialize({
			-- 	msgType = msgType;
			-- 	msg = msg;
			-- 	-- userID = userID;
			-- 	-- id = user.id;
			-- 	username = user.username;
			-- }))
			rednet.send(user.id, {
				side = 'server';
				msgType = msgType;
				msg = msg;
				userID = userID;
			}, protocol)
		end
	else
		for userID in pairs(users) do
			send(msgType, msg, userID)
		end
	end
end

local tCommands
tCommands = {
	['me'] = function(user, sArgs)
		if string.len(sArgs) > 0 then
			send('action', { user.userID, user.username, sArgs })
		else
			send('msg', { -1, '@', 'Usage: /me [words]' }, user.userID)
		end
	end,
	['nick'] = function(user, sArgs)
		if string.len(sArgs) > 0 then
			local oldName = user.username
			user.username = sArgs
			send('nick', { user.userID, oldName, sArgs })
		else
			send('msg', { -1, -1, '@', 'Usage: /nick [nickname]' }, user.userID)
		end
	end,
	['users'] = function(user, sArgs)
		send('msg', { -1, '@', 'Connected Users:' }, user.userID)
		local sUsers = ''
		for userID, user in pairs(users) do
			sUsers = sUsers .. ' ' .. user.username
		end
		send('msg', { -1, '@', sUsers }, user.userID)
	end,
	['help'] = function(user, sArgs)
		send('msg', { -1, '@', 'Available commands:' }, user.userID)
		local sCommands = ''
		for sCommand, fnCommand in pairs(tCommands) do
			sCommands = sCommands .. ' /' .. sCommand
		end
		send('msg', { -1, '@', sCommands..' /logout' }, user.userID)
	end,
}

-- Setup ping pong
local pingPongTimers = {}
function ping(userID)
	local user = users[userID]
	send('pingtc', nil, userID)

	local timer = os.startTimer(15)
	user.bPingPonged = false
	pingPongTimers[timer] = userID
end

function printUsers()
	local x,y = term.getCursorPos()
	term.setCursorPos(1, y - 1)
	term.clearLine()
	if nUsers == 1 then
		print(nUsers .. ' user connected.')
	else
		print(nUsers .. ' users connected.')
	end
end

-- Handle messages
local ok, error = pcall(function()
	parallel.waitForAny(function()
		while true do
			local sEvent, timer = os.pullEvent('timer')
			local userID = pingPongTimers[timer]
			if userID and users[userID] then
				local user = users[userID]
				if user then
					if not user.bPingPonged then
						send('leave', { user.userID, user.username, 'Timeout' })
						users[userID] = nil
						nUsers = nUsers - 1
						printUsers()
					else
						ping(userID)
					end
				end
			end
		end
	end,
	function()
		while true do
			local nSenderID, msg = rednet.receive(protocol)
			if type(msg) == 'table' then
				local userID = msg.userID
				local user = users[userID]

				-- print('got: ' .. textutils.serialize({
				-- 	msgType = msg.msgType;
				-- 	msg = msg.msg;
				-- 	-- userID = userID;
				-- 	-- nSenderID = nSenderID;
				-- 	username = user and user.username or msg.msg
				-- }))

				if msg.msgType == 'login' then
					-- Login from new client
					local username = msg.msg
					if userID and username then
						users[userID] = {
							id = nSenderID;
							userID = userID;
							username = username;
						}
						nUsers = nUsers + 1
						printUsers()
						send('join', { userID, username })
						ping(userID)
					end

				else
					-- Something else from existing client
					if user and user.id == nSenderID then
						-- print(msg.msgType)
						if msg.msgType == 'logout' then
							send('leave', { user.userID, user.username, msg.msg })
							users[userID] = nil
							nUsers = nUsers - 1
							printUsers()

						elseif msg.msgType == 'chat' then
							local chat = msg.msg
							if chat then
								local sCommand = string.match(chat, '^/([a-z]+)')
								if sCommand then
									local fnCommand = tCommands[sCommand]
									if fnCommand then
										local sArgs = string.sub(chat, string.len(sCommand)+3)
										fnCommand(user, sArgs)
									else
										send('msg', { -1, '@', 'Unrecognised command: /'..sCommand }, user.userID)
									end
								else
									send('msg', { user.userID, user.username, chat })
								end
							end

						elseif msg.msgType == 'pingts' then
							send('pongtc', nil, user.userID)

						elseif msg.msgType == 'pongts' then
							user.bPingPonged = true

						end
					end
				end
			 end
		end
	end)
end)
if not ok then
	printError(error)
end

-- Unhost server
send('kick')
rednet.unhost(protocol)