Copas Example

wiki

This is a very simple example of implementing a TCP socket server by utilizing the Copas library ("copas") [1]. The server listens for connections, and when it receives a connection, it echoes a greeting, reads one line, and then closes the connection.

require "copas"

function handler(c, host, port)

	local peer = host .. ":" .. port

	print("connection from", peer)

	c:send("Hello\r\n")

	print("data from", peer, (c:receive"*l"))

end

copas.addserver(assert(socket.bind("*",2220)),

                function(c) return handler(copas.wrap(c), c:getpeername()) end

)

copas.loop()

The following server is only slightly more advanced.

require "copas"



local function simple(host, port, handler)

    return copas.addserver(assert(socket.bind(host, port)),

        function(c)

            return handler(copas.wrap(c), c:getpeername())

        end)

end



local function example_handler(c, host, port)

    local peer = host .. ":" .. port

    print("example connection from", peer)

    c:send("Hello\r\n")

    print("data from", peer, (c:receive"*l"))

    print("example termination from", peer)

end



local function daytime_handler(c, host, port)

    print("daytime connection from", host, port)

    c:send(os.date() .. '\r\n')

end



local function echo_handler(c, host, port)

    print("echo connection from", host, port)

    repeat

        local line = c:receive"*l"

        if line then c:send(line .. '\r\n') end

    until not line

    print("echo termination from", host, port)

end



local function discard_handler(c, host, port)

    print("discard connection from", host, port)

    repeat until not c:receive(100)

    print("discard termination from", host, port)

end



-- Use 0 to listen on the standard (privileged) ports.

local offset = ... or 10000



simple("*", offset + 7, echo_handler)

simple("*", offset + 9, discard_handler)

simple("*", offset + 13, daytime_handler)

simple("*", offset + 57, example_handler)



return copas.loop()

Copas Example

See Also