Amethyst Server

-- Beware, horrible code lurks below, waiting to strike a carefree programmer.

local d = false
local mod = nil
for k, v in pairs(peripheral.getNames()) do
	if peripheral.getType(v) == "modem" then
		rednet.open(v)
		mod = peripheral.wrap(v)
		d = true
	end
end
if not d or not mod then
	error("A modem is required!")
end

-- Some functions

local dns_channel = 331
local args = {...}
local hostname = args[1] or "test.net"

local function download_file(url, target)
	local ht = http.get(url)
	local data = ht.readAll()
	ht.close()
	local file = fs.open(target, "w")
	file.write(data)
	file.close()
end

local function read_file(target)
	local file = fs.open(target, "r")
	local data = file.readAll()
	file.close()
	return data
end

-- API Loading
local function getAPI(name, url)
	local apiloc = "/" .. name
	if (not fs.exists(apiloc)) then
		local newapiloc = shell and shell.resolveProgram(name) or nil
		if type(newapiloc) ~= "string" then
			download_file(url, "/" .. name)
		else
			apiloc = newapiloc
		end
	end
	os.loadAPI(apiloc)
	if not _G[name] then
		error(name .. " failed to load!", 0)
		return
	end
end

getAPI("ringnet", "https://pastebin.com/raw/bnDHMbNx")
ringnet.openChannel(32031)

-- The actual coroutines
parallel.waitForAll(
	function()
		ringnet.connectionHandler(true)
	end,
	ringnet.pingHandler,
	function()
		while true do
			local ev, from, data, dist = os.pullEvent("secure_receive")
			if (ev ~= nil) then
				if (type(data) ~= "table") then
					data = textutils.unserialize(tostring(data))
				end
				if not data then
					return
				end
				if (type(data.type) == "string") then
					local path = fs.combine("/www", fs.combine("", tostring(data.path)):gsub("%.", ""))
					if (data.type == "AMETHYSTGET" and type(data.path) == "string" and fs.exists(path)) then
						local file = fs.open(path, "r")
						local stuff = file.readAll()
						file.close()
						sendData(
							from,
							get_frq(from),
							textutils.serialize(
								{
									type = "AMETHYSTDATA",
									data = stuff
								}
							)
						)
					end
				end
			end
			sleep(0)
		end
	end
)