Erlang 聊天室
因为之前有使用过PyQt做过聊天室的功能，现在使用Erlang去重写聊天室，去了解这门语言，有兴趣的朋友可以写基于Qt客户端和Erlang的服务端去交互，本Demo统一使用Erlang去实现客户端。
所需知识
- 网络编程中接受请求的套接字创建过程如下（四步记忆）
- 第一步：调用socket函数
- 第二步：调用bind函数分配IP地址和端口
- 第三步：调用listen函数转为可接收请求状态
- 第四步：调用accept函数受理连接请求
服务端监听Socket
- 第一部分初始化ets表，可选参数可自由选择
start_server() ->
ets:new(id, [ordered_set, public, named_table, {write_concurrency, true}, {read_concurrency, true}]),
case gen_tcp:listen(1234, [binary, {packet, 0}, {active, true}]) of
{ok, ListenSocket} ->
spawn(fun() -> client_connect(ListenSocket) end);
{error, Reason} ->
io:format("~p~n", [Reason])
end.
- 第二部分处理请求
- 这部分要注意gen_tcp:accept()函数，这部分会处理本次请求才会去处理新的请求，即顺序处理，为了解决这个问题，使用了并发处理，每次连接都会开一个新进程去处理，这样就可以并发处理了。
client_connect(ListenSocket) ->
case gen_tcp:accept(ListenSocket) of
{ok, Socket} ->
%% 进行验证，看是否是注册还是登录
spawn(fun() -> client_connect(ListenSocket) end),
loop(Socket);
{error, Reason} ->
io:format("~p~n", [Reason])
end.
- 第三部分While True循环
- 这部分分别去处理客户端的发送信息，如注册，登录，退出，私聊，群聊。
loop(Socket) ->
receive
{tcp, Socket, Bin} ->
[Id, Sign, PassWord, SendId, MessageInfos] = binary_to_term(Bin),
if
Sign =:= register_user ->
Info = register_user(Id, PassWord, Socket),
gen_tcp:send(Socket, term_to_binary(Info)),
loop(Socket);
Sign =:= login_user ->
Info = login_user(Id, PassWord, Socket),
gen_tcp:send(Socket, term_to_binary(Info)),
loop(Socket);
Sign =:= login_out ->
Info = login_out(Id, Socket),
gen_tcp:send(Socket, term_to_binary(Info)),
loop(Socket);
Sign =:= private_msg ->
private_chat(SendId, Socket, MessageInfos),
loop(Socket);
Sign =:= group_msg ->
group_chat(Socket, MessageInfos),
loop(Socket);
true ->
io:format("error sign ~n"),
loop(Socket)
end;
{tcp_closed, Socket} ->
io:format("Server socket closed ~n")
end.
-
功能部分
- 用户注册
- 使用ets库的lookup函数去检查用户是否已经注册
%% 用户注册 register_user(Id, PassWord, Socket) -> case ets:lookup(id, Id) of [_Ok] -> io:format("Account is fail ~n"), "Account is exist ~n"; _ -> ets:insert(id, {Id, PassWord, 0, Socket}), "register successed ~n" end.- 用户登录
- 首先使用ets库的match_object函数的去检查用户登录情况，这里其实写详细点，就是有三种可能，用户账号不存在，密码错误，用户已经在线。同时如果登录成功，应该设置用户为在线状态和给用户分配socket。
%% 用户登录 login_user(Id, PassWord, Socket) -> case ets:match_object(id, {Id, PassWord, 0, Socket}) of [_Ok] -> ets:update_element(id, Id, [{3, 1}, {4, Socket}]), "login successed"; Reson -> io:format("login is fail ~n ~p", [Reson]), "Password error or Account is not exist ~n" end.- 用户退出
- 退出用户,首先判断用户已经在线，才能下线，同时把在线状态和socket设置为0。
%% 退出用户 login_out(Id, Socket) -> %% 因为id对应唯一socket，所以不需要PassWord case ets:match_object(id, {Id, '_', 1, Socket}) of [_Ok] -> ets:update_element(id, Id, [{3, 0}, {4, 0}]), "login successed"; _ -> io:format("out is fail ~n"), "login is fail" end.- 群聊
- 首先判断发送用户是否在线，然后递归给在线用户发送信息。
%% 群聊 group_chat(Socket, MessageInfos) -> case ets:match_object(id, {'_', '_', 1, Socket}) of [{Id, _, _, _}] -> Res = ets:match_object(id, {'_', '_', 1, '_'}), case Res =:= [] of true -> io:format("no person online ~p ~n", [Res]); _ -> group_send_msg(Res, Id, MessageInfos) end; _ -> io:format("group chat is fail ~n") end. %% 群聊发送 group_send_msg([], _Id, _MessageInfos) -> next; group_send_msg([Info | Infos], Id, MessageInfos) -> {_, _, _, Socket} = Info, gen_tcp:send(Socket, term_to_binary("from: " ++ integer_to_list(Id) ++ "say: " ++ MessageInfos)), group_send_msg(Infos, Id, MessageInfos).- 在线私聊
- 由于没有设置字段去存取聊天记录，所以使用只有在线状态下的聊天。
%% 在线私聊 private_chat(SendId, Socket, MessageInfos) -> case ets:match_object(id, {'_', '_', 1, Socket}) of [{Id, _, _, _}] -> Res = ets:match_object(id, {SendId, '_', 1, '_'}), case Res =:= [] of true -> io:format("send person not online ~p ~n", [Res]); _ -> private_send_msg(Res, Id, MessageInfos) end; _ -> io:format("private chat is fail ~n") end. %% 私聊发送 private_send_msg([Info], Id, MessageInfos) -> {_, _, _, Socket} = Info, gen_tcp:send(Socket, term_to_binary("from: " ++ integer_to_list(Id) ++ "say: " ++ MessageInfos)).
客户端实现
- 客户端进程
- 并把socket控制进程设置为loop的进程号
%客户端
start_client() ->
{ok, Socket} = gen_tcp:connect("localhost", 1234, [binary, {packet, 0}]), %连接服务器
%新建一个进程负责接收消息
Pid = spawn(fun() -> loop() end),
gen_tcp:controlling_process(Socket, Pid),
sendMsg(Socket).
loop() ->
receive
{tcp, _Socket, Bin} ->
Res = binary_to_term(Bin),
io:format("Message Info! ~p ~n", [Res]),
loop();
{tcp_closed, _Socket} ->
io:format("Socket is closed! ~p ~n")
end.
- 客户端操作
- 对应服务端的功能部分
sendMsg(Socket) ->
S = io:get_line("select operation: "),
{Sign, _Info} = string:to_integer(S),
SendMsg = operation_message(Sign),
gen_tcp:send(Socket, term_to_binary(SendMsg)),
sendMsg(Socket).
%% 用户注册
operation_message(1) ->
I = io:get_line("id: "),
{Id, _Info} = string:to_integer(I),
Password = io:get_line("register password: "),
[Id, register_user, Password, 0, 0];
%% 用户登录
operation_message(2) ->
I = io:get_line("id:"),
Password = io:get_line("login password: "),
{Id, _Info} = string:to_integer(I),
[Id, login_user, Password, 0, 0];
%% 用户退出
operation_message(3) ->
I = io:get_line("id: "),
{Id, _Info} = string:to_integer(I),
[Id, login_out, 0, 0, 0];
%% 私聊
operation_message(4) ->
Sd = io:get_line("send_id: "),
Msg = io:get_line("MsgInfo: "),
{SendId, _Info} = string:to_integer(Sd),
[0, private_msg, 0, SendId, Msg];
%% 群聊
operation_message(5) ->
Msg = io:get_line("MsgInfo: "),
[0, group_msg, 0, 0, Msg];
%% 无效操作
operation_message(_) ->
Msg = io:format("invalid_operation ~n"),
[0, invalid_operation, 0, 0, Msg].
完整源代码
- 服务端
%%%-------------------------------------------------------------------
%%% @author Curry
%%% @copyright (C) 2021, <COMPANY>
%%% @doc
%%%
%%% @end
%%% Created : 08. 8月 2021 13:33
%%%-------------------------------------------------------------------
-module(chatserv).
-author("Curry").
%% API
-compile(export_all).
-import(ets, [insert_new/2]).
start_server() ->
ets:new(id, [ordered_set, public, named_table, {write_concurrency, true}, {read_concurrency, true}]),
case gen_tcp:listen(1234, [binary, {packet, 0}, {active, true}]) of
{ok, ListenSocket} ->
spawn(fun() -> client_connect(ListenSocket) end);
{error, Reason} ->
io:format("~p~n", [Reason])
end.
client_connect(ListenSocket) ->
case gen_tcp:accept(ListenSocket) of
{ok, Socket} ->
%% 进行验证，看是否是注册还是登录
spawn(fun() -> client_connect(ListenSocket) end),
loop(Socket);
{error, Reason} ->
io:format("~p~n", [Reason])
end.
loop(Socket) ->
receive
{tcp, Socket, Bin} ->
[Id, Sign, PassWord, SendId, MessageInfos] = binary_to_term(Bin),
if
Sign =:= register_user ->
Info = register_user(Id, PassWord, Socket),
gen_tcp:send(Socket, term_to_binary(Info)),
loop(Socket);
Sign =:= login_user ->
Info = login_user(Id, PassWord, Socket),
gen_tcp:send(Socket, term_to_binary(Info)),
loop(Socket);
Sign =:= login_out ->
Info = login_out(Id, Socket),
gen_tcp:send(Socket, term_to_binary(Info)),
loop(Socket);
Sign =:= private_msg ->
private_chat(SendId, Socket, MessageInfos),
loop(Socket);
Sign =:= group_msg ->
group_chat(Socket, MessageInfos),
loop(Socket);
true ->
io:format("error sign ~n"),
loop(Socket)
end;
{tcp_closed, Socket} ->
io:format("Server socket closed ~n")
end.
%% 用户注册
register_user(Id, PassWord, Socket) ->
case ets:lookup(id, Id) of
[_Ok] ->
io:format("Account is fail ~n"),
"Account is exist ~n";
_ ->
ets:insert(id, {Id, PassWord, 0, Socket}),
"register successed ~n"
end.
%% 用户登录
login_user(Id, PassWord, Socket) ->
case ets:match_object(id, {Id, PassWord, 0, Socket}) of
[_Ok] ->
ets:update_element(id, Id, [{3, 1}, {4, Socket}]),
"login successed";
Reson ->
io:format("login is fail ~n ~p", [Reson]),
"Password error or Account is not exist ~n"
end.
%% 退出用户
login_out(Id, Socket) ->
%% 因为id对应唯一socket，所以不需要PassWord
case ets:match_object(id, {Id, '_', 1, Socket}) of
[_Ok] ->
ets:update_element(id, Id, [{3, 0}, {4, 0}]),
"login successed";
_ ->
io:format("out is fail ~n"),
"login is fail"
end.
%% 群聊
group_chat(Socket, MessageInfos) ->
case ets:match_object(id, {'_', '_', 1, Socket}) of
[{Id, _, _, _}] ->
Res = ets:match_object(id, {'_', '_', 1, '_'}),
case Res =:= [] of
true ->
io:format("no person online ~p ~n", [Res]);
_ ->
group_send_msg(Res, Id, MessageInfos)
end;
_ ->
io:format("group chat is fail ~n")
end.
%% 群聊发送
group_send_msg([], _Id, _MessageInfos) ->
next;
group_send_msg([Info | Infos], Id, MessageInfos) ->
{_, _, _, Socket} = Info,
gen_tcp:send(Socket, term_to_binary("from: " ++ integer_to_list(Id) ++ "say: " ++ MessageInfos)),
group_send_msg(Infos, Id, MessageInfos).
%% 在线私聊
private_chat(SendId, Socket, MessageInfos) ->
case ets:match_object(id, {'_', '_', 1, Socket}) of
[{Id, _, _, _}] ->
Res = ets:match_object(id, {SendId, '_', 1, '_'}),
case Res =:= [] of
true ->
io:format("send person not online ~p ~n", [Res]);
_ ->
private_send_msg(Res, Id, MessageInfos)
end;
_ ->
io:format("private chat is fail ~n")
end.
%% 私聊发送
private_send_msg([Info], Id, MessageInfos) ->
{_, _, _, Socket} = Info,
gen_tcp:send(Socket, term_to_binary("from: " ++ integer_to_list(Id) ++ "say: " ++ MessageInfos)).
- 客户端
%%%-------------------------------------------------------------------
%%% @author Curry
%%% @copyright (C) 2021, <COMPANY>
%%% @doc
%%%
%%% @end
%%% Created : 08. 8月 2021 14:03
%%%-------------------------------------------------------------------
-module(chatclient).
-author("Curry").
%% API
-compile(export_all).
%客户端
start_client() ->
{ok, Socket} = gen_tcp:connect("localhost", 1234, [binary, {packet, 0}]), %连接服务器
%新建一个进程负责接收消息
Pid = spawn(fun() -> loop() end),
gen_tcp:controlling_process(Socket, Pid),
sendMsg(Socket).
loop() ->
receive
{tcp, _Socket, Bin} ->
Res = binary_to_term(Bin),
io:format("Message Info! ~p ~n", [Res]),
loop();
{tcp_closed, _Socket} ->
io:format("Socket is closed! ~p ~n")
end.
sendMsg(Socket) ->
S = io:get_line("select operation: "),
{Sign, _Info} = string:to_integer(S),
SendMsg = operation_message(Sign),
gen_tcp:send(Socket, term_to_binary(SendMsg)),
sendMsg(Socket).
%% 用户注册
operation_message(1) ->
I = io:get_line("id: "),
{Id, _Info} = string:to_integer(I),
Password = io:get_line("register password: "),
[Id, register_user, Password, 0, 0];
%% 用户登录
operation_message(2) ->
I = io:get_line("id:"),
Password = io:get_line("login password: "),
{Id, _Info} = string:to_integer(I),
[Id, login_user, Password, 0, 0];
%% 用户退出
operation_message(3) ->
I = io:get_line("id: "),
{Id, _Info} = string:to_integer(I),
[Id, login_out, 0, 0, 0];
%% 私聊
operation_message(4) ->
Sd = io:get_line("send_id: "),
Msg = io:get_line("MsgInfo: "),
{SendId, _Info} = string:to_integer(Sd),
[0, private_msg, 0, SendId, Msg];
%% 群聊
operation_message(5) ->
Msg = io:get_line("MsgInfo: "),
[0, group_msg, 0, 0, Msg];
%% 无效操作
operation_message(_) ->
Msg = io:format("invalid_operation ~n"),
[0, invalid_operation, 0, 0, Msg].