File downloader

main.lua (on mobile)

-- most of this is not needed fo the download, but this code keeps the app running even when there is an error
-- when an error happens, this code offers the option to update the files through the server
-- start at line 200 if you only want the file download service 

function run()

	if love.math then
		love.math.setRandomSeed(os.time())
	end

	if love.load then love.load(arg) end

	-- We don't want the first frame's dt to include time taken by love.load.
	if love.timer then love.timer.step() end

	local dt = 0

	-- Main loop time.
	while true do
		-- Process events.
		if love.event then
			love.event.pump()
			for name, a,b,c,d,e,f in love.event.poll() do
				if name == "quit" then
					if not love.quit or not love.quit() then
						return a
					end
				end
				love.handlers[name](a,b,c,d,e,f)
			end
		end

		-- Update dt, as we'll be passing it to update
		if love.timer then
			love.timer.step()
			dt = love.timer.getDelta()
		end

		-- Call update and draw
		if love.update then love.update(dt) end -- will pass 0 if love.timer is disabled

		if love.graphics and love.graphics.isActive() then
			love.graphics.clear(love.graphics.getBackgroundColor())
			love.graphics.origin()
			if love.draw then love.draw() end
			love.graphics.present()
		end

		if love.timer then love.timer.sleep(0.001) end
	end

end

function love.errhand(msg)
	msg = tostring(msg)

	if msg:find("[QUIT]") then
		return true
	end

	--local ip = "127.0.0.1" --"*"
	local port = 6667 --6667
 
	if not love.window or not love.graphics or not love.event then
		return true
	end
 
	if not love.graphics.isCreated() or not love.window.isOpen() then
		local success, status = pcall(love.window.setMode, 800, 600)
		if not success or not status then
			return true
		end
	end
 
	-- Reset state.
	if love.mouse then
		love.mouse.setVisible(true)
		love.mouse.setGrabbed(false)
		love.mouse.setRelativeMode(false)
	end

	if love.keyboard then
		love.keyboard.setTextInput(false)
	end

	if love.joystick then
		-- Stop all joystick vibrations.
		for _,v in ipairs(love.joystick.getJoysticks()) do
			v:setVibration()
		end
	end
	if love.audio then love.audio.stop() end
	love.graphics.reset()
	local font = love.graphics.setNewFont(30)
 
	love.graphics.setBackgroundColor(89, 157, 220)
	love.graphics.setColor(255, 255, 255, 255)
 
	local trace = debug.traceback()
 
	love.graphics.clear(love.graphics.getBackgroundColor())
	love.graphics.origin()
 
	local err = {}
 
	table.insert(err, "Error\n")
	table.insert(err, msg.."\n\n")
 
	for l in string.gmatch(trace, "(.-)\n") do
		if not string.match(l, "boot.lua") then
			l = string.gsub(l, "stack traceback:", "Traceback\n")
			table.insert(err, l)
		end
	end
 
	local p = table.concat(err, "\n")
 
	p = string.gsub(p, "\t", "")
	p = string.gsub(p, "%[string \"(.-)\"%]", "%1")

	local w,h = love.graphics.getDimensions()
	local turn = false

	if w > h then 
		love.graphics.rotate(math.rad(-90))
		love.graphics.translate(-h,0)
		turn = true
		w,h = h,w
	end

	local showUpdate = true
	local update = false

	local pos1_y = h-120
	local pos2_y = h-240
	local pos_x = 20

	local pos_w = w-40
	local pos_h = 100

	local retVal = true
 
	local function draw()
		local pos = 70
		love.graphics.setColor(255,255,255,255)
		love.graphics.clear(love.graphics.getBackgroundColor())
		love.graphics.printf(tostring(p), pos, pos, love.graphics.getWidth() - pos)

		love.graphics.setColor(200,0,0,255)

		love.graphics.rectangle("fill",pos_x,pos1_y,pos_w,pos_h)

		love.graphics.setColor(255,255,255,255)

		local tw = font:getWidth("CLOSE")
		local th = font:getHeight()

		love.graphics.print("CLOSE", pos_x + (pos_w-tw)/2,pos1_y + (pos_h-th)/2)

		if showUpdate then
			love.graphics.setColor(192,192,192,255)

			love.graphics.rectangle("fill",pos_x,pos2_y,pos_w,pos_h)

			love.graphics.setColor(0,0,0,255)
			local tw = font:getWidth("UPDATE")
			local th = font:getHeight()

			love.graphics.print("UPDATE", pos_x + (pos_w-tw)/2,pos2_y + (pos_h-th)/2)
		end

		love.graphics.present()
	end
 	
 	local updateState = 0

	local service;

	local net = require("net")

	net.close()

	while true do
		love.event.pump()
 
		for e, a, b, c, d in love.event.poll() do
			if e == "quit" then
				return true
			elseif e == "keypressed" and a == "escape" then
				if not update then
					return false
				end
			elseif e == "touchpressed" then
				local handled = update and true or false
				if turn then
					b,c=c,b
				end
				if b > pos_x and b < pos_x + pos_w then
					if c > pos1_y and c < pos1_y + pos_h then
						-- Close
						return true
					elseif c > pos2_y and c < pos2_y + pos_h and showUpdate then
						-- update
						update = true
						service = net.getDiscoverService()
						local a,b,c = service(port,"TCPING","TCPONG",10)
						if a == "Finished" then
							net.setIp(b,c)
							updateState = 2
							service = net.getTCPConnection()
						end

						updateState = 1
						handled = true
						showUpdate = false
					end
				end

				if not handled then
					local name = love.window.getTitle()
					if #name == 0 or name == "Untitled" then name = "Game" end
					local buttons = {"OK", "Cancel"}
					local pressed = love.window.showMessageBox("Quit "..name.."?", "", buttons)
					if pressed == 1 then
						return false
					end
				end
			elseif e == "mousepressed" and not d then
				love.event.push("touchpressed",1,a,b)
			end
		end


		draw()

		if update then
			if updateState == 1 then
				local a,b,c = service(love.timer.getDelta())
				p = "Discovering Server...\n Tries: "..tostring(b).."/"..tostring(c)
				if a == "Finished" then
					net.setIp(b,c)
					updateState = 2
					service = net.getTCPConnection()
				elseif not a then
					error(b)
				end
			elseif updateState == 2 then
				local state,err = service()
				if state then
					updateState = 3
					p = "Connected"
					service = net.updateFiles()
				elseif err then
					error(err)
				else
					p = "Connecting to server..."
				end
			elseif updateState == 3 then
				local state,a,b,c = pcall(service)
				if state and a and b == "Finished" then
					local function getAllFiles(path,data)
						local data = data or {}
						local files = love.filesystem.getDirectoryItems(path)
						for _,v in pairs(files) do
							if love.filesystem.isDirectory(path.."/"..tostring(v)) then
								getAllFiles(path.."/"..tostring(v),data)
							else
								local str = (path.."/"..tostring(v)):gmatch(".+%.")()
								str = str:gsub("/","."):sub(2,-2)
								data[str] = true
							end
						end
						return data
					end
					local state,files = pcall(getAllFiles,"/mobile")
					for i in pairs(files) do
						if package.loaded[i] then
							package.loaded[i] = nil
						end
					end
					retVal = false
					break
				end
				p = table.concat({a,b,c},"\n")
			end
		end
 
		if love.timer then
			love.timer.sleep(0.1)
		end
	end

	return retVal
end

function love.run()
	while true do
		local reload = false
		if love.filesystem.isFile("mobile/init.lua") then
			local state,err = pcall(require,"mobile.init")
			if not state then
				love.errhand(err)
			end
		else
			love.errhand("No init file found. Please update...")
		end

		local state, br,err = xpcall(run,love.errhand)
		if br == true then
			break
		end
	end
end

main.lua (on server)

io.stdout:setvbuf'no'
local socket = require("socket")

local udp = socket.udp()

udp:settimeout(0)
udp:setsockname("*",6667)
udp:setoption("broadcast",true)

local tcp = socket.tcp()
tcp:settimeout(0)
tcp:bind("*",6667)
tcp:listen()
tcp:setoption("reuseaddr",true)


local someRandomIP = "192.168.1.122" --This address you make up
local someRandomPort = "3102" --This port you make up  
local mySocket = socket.udp() --Create a UDP socket like normal
--This is the weird part, we need to set the peer for some reason
mySocket:setpeername(someRandomIP,someRandomPort) 
--I believe this binds the socket
--Then we can obtain the correct ip address and port
local myDevicesIpAddress, somePortChosenByTheOS = mySocket:getsockname()-- returns IP and Port 

local clients = {}

local transfers = {}

local bytes = 4096

local function getAllFiles(path)
	local files = love.filesystem.getDirectoryItems(path)
	local data = {}
	for i,v in pairs(files) do
		if love.filesystem.isDirectory(path.."/"..tostring(v)) then
			data[v] = getAllFiles(path.."/"..tostring(v))
		else
			local locPath = (path.."/"..tostring(v)):sub(8)
			data[v] = {file = true,time = love.filesystem.getLastModified(path.."/"..tostring(v)),path = locPath}
		end
	end
	return data
end


function updateClientData(client,id,bytes)
	local client = client
	client:settimeout(0)
	local files = getAllFiles("/mobile")
	local bytesPerMsg = bytes or 4096
	local id = id
	local size = 0
	coroutine.yield(true)

	local function loopFiles(tab)
		for i,v in pairs(tab) do
			if v.file then
				client:send("TCFILE#"..tostring(v.path).."#"..tostring(v.time).."#\n")
				local ans = ""
				while true do
					local msg = client:receive("*l")
					if msg then
						ans = msg
						break
					else
						coroutine.yield(true)
					end
				end
				if ans == "TCUPDATEFILE" then

					local file = love.filesystem.newFile("/mobile"..v.path)
					size = file:getSize()
					client:send("TCSIZE#"..tostring(file:getSize()).."#"..tostring(bytesPerMsg).."#\n")

					file:open("r")
					client:settimeout(0.1)
					while true do 
						local payload = file:read(bytesPerMsg)
						file:seek(bytesPerMsg)
						if payload then
							size = size - bytesPerMsg
							client:send(payload)
							if size <= 0 then
								break
							end
							coroutine.yield(true)
						else
							break
						end
					end
					local ans = ""
					while true do
						local msg = client:receive("*l")
						if msg then
							ans = msg
							break
						else
							coroutine.yield(true)
						end
					end
					print(ans)
				end
			else
				loopFiles(v)
			end
		end
	end

	loopFiles(files)

	return true, id
end



function love.update(dt)
	love.window.setTitle(tostring(love.timer.getFPS()))
	local msg,addr,port = udp:receivefrom()
	if msg then
		print(msg,addr,port)
		if msg == "TCPING" then
			local s = "TCPONG"
			udp:sendto(s,addr,port)
		end
	end

	local client = tcp:accept()
	if client then
		print(client)
		client:settimeout(0)
		table.insert(clients,{socket = client, used = false})
	end
	for i,v in pairs(clients) do
		if not v.used then
			local msg = v.socket:receive("*l")
			if msg then
				print(msg)
				if msg == "TCUPDATEFILES" then
					local coro = coroutine.wrap(updateClientData)
					v.used = true
					coro(v.socket, i)
					table.insert(transfers,coro)
				elseif msg == "TCDONE" then
				elseif msg == "TCQUIT" then
					for j,k in pairs(users) do
						if k.client == i then
							clients[i] = nil
						end	
					end
				else
					local data = {}
					for dat in tostring(msg):gmatch(".-#") do
						table.insert(data,dat:sub(1,-2))
					end

					if data[1] == "TCCONNECT" then
						users[tostring(data[2])] = {
							client = i
						}
					end

				end
			end
		end
	end

	for i,v in pairs(transfers) do
		local res,id = v()
		if res and id  then
			clients[id].socket:send("TCRELOAD#\n")
			transfers[i] = nil
			clients[id].used = false
		end
	end
end

function love.draw()
	love.graphics.setColor(255,255,255,255)
	love.graphics.print(tostring(myDevicesIpAddress),10,10)
end


function love.quit()
	udp:close()
	tcp:close()
end


function love.quit()
	udp:close()
	tcp:close()
end

net.lua (on mobile)

-- searches for server, gets servers ip and downloads all files
-- it tries to check which files to download, but that doesn't work right now
local net = {}
	
net.socket = require("socket")

function net.setIp(ip,port)
	net.ip = ip
	net.port = port
	net.bytes = 4096
end

function net.close()
	if net.tcp and net.tcp.close then
		pcall(net.tcp.send,net.tcp,"TCQUIT")
		pcall(net.tcp.close,net.tcp)
	end

	if net.udp and net.udp.close then
		pcall(net.udp.close,net.udp)
	end
	net.connected = false
end

function net.isConnected()
	return net.connected
end

function net.getTCP()
	return net.tcp
end

local function discoverServer(port,ping,pong,maxtries)
	net.udp = net.socket.udp()
	net.udp:settimeout(0)
	net.udp:setoption("broadcast",true)
	local timer = 5
	local port = port
	local ping = ping or "PING"
	local pong = pong or "PONG"
	local dt = 0
	local tries = 0
	local maxtries = maxtries or 10
	while true do
		timer = timer + dt
		if timer >= 5 then
			timer = timer - 5
			tries = tries + 1
			if tries >= maxtries then
				net.udp:close()
				return false,"Server not found"
			end
			local state, err = net.udp:sendto(ping,"255.255.255.255",port)
			if not state then
				return false, err
			else
				dt = coroutine.yield("working",tries,maxtries)
			end
		end
		local msg, addr, por = net.udp:receivefrom()
		if msg == pong then
			net.udp:close()
			return "Finished",addr,por
		else
			dt = coroutine.yield("working",tries,maxtries)
		end
	end
end

function net.getDiscoverService()
	return coroutine.wrap(discoverServer)
end

function getTCP()
	net.tcp = net.socket.tcp()
	net.tcp:settimeout(1)
	local state,err = net.tcp:connect(net.ip, net.port)
	if not state then
		return false, err
	else
		net.connected = true
		return true
	end

	while true do
		local data = socket.select({net.tcp}, {net.tcp} ,0.1)
		if #data > 0 then
			net.connected = true
			return true
		else
			coroutine.yield(false)
		end
	end
end

function net.getTCPConnection()
	return coroutine.wrap(getTCP)
end

function updateFiles(...)
	net.tcp:settimeout(0.1)

	local function getAllFiles(path)
		local files = love.filesystem.getDirectoryItems(path)
		local data = {}
		for _,v in pairs(files) do
			if love.filesystem.isDirectory(path.."/"..tostring(v)) then
				data[v] = getAllFiles(path.."/"..tostring(v))
			else
				data[v] = "FILE"
			end
		end
		return data
	end
	

	local files = getAllFiles("/mobile")
	
	net.tcp:send("TCUPDATEFILES\n")
	local filebytes =  0
	local bytesPerMsg = 4096
	local receivedBytes = 0
	local fileTransfer = false
	local filePath = ""
	local file;
	while true do
		if not fileTransfer then
			local msg = net.tcp:receive("*l")
			if msg then
				local data = {}
				for dat in tostring(msg):gmatch(".-#") do
					table.insert(data,dat:sub(1,-2))
				end
				if data[1] == "TCFILE" then
					local file = files
					for path in data[2]:gmatch("/.-") do
						path = path:sub(2)
						if file[path] then
							if file[path] == "FILE" then
								local modtime, errormsg = love.filesystem.getLastModified(tostring(data[2]) )
								if errormsg then
									net.tcp:send("TCUPDATEFILE\n")
									filePath = tostring(data[2])
									break
								else
									if tostring(modtime) == data[3] then
										net.tcp:send("TCNEXTFILE\n")
										break
									else
										net.tcp:send("TCUPDATEFILE\n")
										filePath = tostring(data[2])
										break
									end
								end
							else
								file = file[path]
							end
						else
							net.tcp:send("TCUPDATEFILE\n")
							filePath = tostring(data[2])
							break
						end
					end
				elseif data[1] == "TCSIZE" then
					filebytes = tonumber(data[2])
					bytesPerMsg = data[3] or bytesPerMsg
					fileTransfer = true
					if love.filesystem.exists("/mobile"..filePath) then
						love.filesystem.remove("/mobile"..filePath)
					end
					local dirPath = filePath:gmatch(".+/")()
					if dirPath then
						love.filesystem.createDirectory("/mobile"..tostring(dirPath))
					end
					file = love.filesystem.newFile("/mobile"..filePath)
					file:open("w")
					receivedBytes = 0
				elseif data[1] == "TCRELOAD" then
					return true, "Finished"
				end
			end
		else
			if receivedBytes + bytesPerMsg > filebytes then
				bytesPerMsg = filebytes-receivedBytes
			end
			local payload, err, partial = net.tcp:receive(bytesPerMsg)
			if payload then
				receivedBytes = receivedBytes + bytesPerMsg
				file:write(payload)
				if receivedBytes >= filebytes then
					file:close()
					net.tcp:send("TCDONE\n")
					fileTransfer = false
				end
			end
		end
		coroutine.yield("working",fileTransfer and "Receiving file...\n"..tostring(filePath).."\n"..tostring(receivedBytes).." / "..tostring(filebytes).."bytes" or "Updating files\n"..tostring(filePath))
	end
end

function net.updateFiles()
	return coroutine.wrap(updateFiles)
end

return net

How to use:
Put the main.lua for mobile and net.lua on your (android) phone and run it. It should display an error that it can't find any init.lua file.

Now start the servers main.lua on any device in the same network. create a folder mobile next to it and put any files for the mobile into it.
That should include an init.lua file, in which your main code (love.load, love.draw, etc) is.

when the server has started, just press the update button on the mobile phone and it 'should' try to find the server by broadcasting a ping.
As soon as the server is found it will copy all files in the mobile folder onto your phone.

When it is done it will try to restart, but that doesn't work yet.

! You need to restart love2d after updating this way ! The new files only show up after a restart