Erlang 各种 Socket 服务器 Demo

TCP Echo server(只接收一次连接):

-module(echo).
-export([main/1, start_serv/0]).


start_serv() ->
    {ok, Listen} = gen_tcp:listen(2345, [binary, {reuseaddr, true}]),
    {ok, Socket} = gen_tcp:accept(Listen),
    loop(Socket),
    gen_tcp:close(Listen).


loop(Socket) ->
    receive
        {tcp, Socket, Bin} ->
            io:format("~p~n", [Bin]),
            ok = gen_tcp:send(Socket, Bin),
            loop(Socket);
        {tcp_closed, Socket} ->
            io:format("closed~n")
    end.


main(_) ->
    start_serv().

TCP Echo server(接受多次连接，处理完一个连接后才能处理第二个连接):

-module(echo).
-compile(export_all).

start_serv() ->
    {ok, Listen} = gen_tcp:listen(2345, [binary, {reuseaddr, true}]),
    tcp_listen(Listen).


tcp_listen(Listen) ->
    {ok, Socket} = gen_tcp:accept(Listen),
    handle_loop(Socket),
    tcp_listen(Listen).


handle_loop(Socket) ->
    receive
        {tcp, Socket, Bin} ->
            io:format("~p~n", [Bin]),
            ok = gen_tcp:send(Socket, Bin),
            handle_loop(Socket);
        {tcp_closed, Socket} ->
            io:format("closed~n")
    end.


main(_) ->
    start_serv().

TCP Echo server(并发型，可同时处理多条连接):

-module(echo).
-compile(export_all).

start_serv() ->
    {ok, Listen} = gen_tcp:listen(2345, [binary, {reuseaddr, true}]),
    tcp_listen(Listen).


tcp_listen(Listen) ->
    {ok, Socket} = gen_tcp:accept(Listen),
    spawn(fun() -> tcp_listen(Listen) end),
    handle_loop(Socket).


handle_loop(Socket) ->
    receive
        {tcp, Socket, Bin} ->
            io:format("~p~n", [Bin]),
            ok = gen_tcp:send(Socket, Bin),
            handle_loop(Socket);
        {tcp_closed, Socket} ->
            io:format("closed~n")
    end.


main(_) ->
    start_serv().

TCP Echo server(半阻塞):

-module(echo).
-compile(export_all).

start_serv() ->
    {ok, Listen} = gen_tcp:listen(2345, [binary,
                                         {active, once},
                                         {reuseaddr, true}]),
    tcp_listen(Listen).


tcp_listen(Listen) ->
    {ok, Socket} = gen_tcp:accept(Listen),
    spawn(fun() -> tcp_listen(Listen) end),
    handle_loop(Socket).


handle_loop(Socket) ->
    inet:setopts(Socket, [{active, once}]),
    receive
        {tcp, Socket, Bin} ->
            io:format("~p~n", [Bin]),
            ok = gen_tcp:send(Socket, Bin),
            handle_loop(Socket);
        {tcp_closed, Socket} ->
            io:format("closed~n")
    end.


main(_) ->
    start_serv().

UDP Echo server:

-module(echo).
-compile(export_all).

server() ->
    {ok, Socket} = gen_udp:open(2345, [binary]),
    loop(Socket).


loop(Socket) ->
    receive
        {udp, Socket, Host, Port, Bin} ->
            gen_udp:send(Socket, Host, Port, Bin),
            loop(Socket)
    end.

未完待续