luasocket/samples/tinyirc.lua

-----------------------------------------------------------------------------
-- Select sample: simple text line server
-- LuaSocket sample files.
-- Author: Diego Nehab
-- RCS ID: $Id$
-----------------------------------------------------------------------------
host = host or "*"
port1 = port1 or 8080
port2 = port2 or 8181
if arg then
    host = arg[1] or host
    port1 = arg[2] or port1
    port2 = arg[3] or port2
end

server1, error = socket.bind(host, port1)
assert(server1, error)
server1:settimeout(1) -- make sure we don't block in accept
server2, error = socket.bind(host, port2)
assert(server2, error)
server2:settimeout(1) -- make sure we don't block in accept

io.write("Servers bound\n")

-- simple set implementation
-- the select function doesn't care about what is passed to it as long as
-- it behaves like a table
function newset()
    local reverse = {}
    local set = {}
    setmetatable(set, { __index = {
        insert = function(set, value) 
            table.insert(set, value)
            reverse[value] = table.getn(set)
        end,
        remove = function(set, value)
            table.remove(set, reverse[value])
            reverse[value] = nil
        end,
    }})
    return set
end

set = newset()

io.write("Inserting servers in set\n")
set:insert(server1)
set:insert(server2)

while 1 do
    local readable, _, error = socket.select(set, nil)
    for _, input in readable do
        -- is it a server socket?
        if input == server1 or input == server2 then
            io.write("Waiting for clients\n")
            local new = input:accept()
            if new then 
                new:settimeout(1)
                io.write("Inserting client in set\n")
                set:insert(new) 
            end
        -- it is a client socket
        else
            local line, error = input:receive()
            if error then 
                input:close()
                io.write("Removing client from set\n")
                set:remove(input) 
            else
            	io.write("Broadcasting line '", line, "'\n")
            	__, writable, error = socket.select(nil, set, 1)
            	if not error then
                	for ___, output in writable do
                    	output:send(line .. "\n")
                	end
            	else io.write("No client ready to receive!!!\n") end
			end
        end
    end
end