[Erlang脚印 0003] gen_tcp

来源:互联网 时间:1970-01-01

常用的gen_tcp用到的函数:

gen_tcp:listen(Port, Options) -> {ok, ListenSocket}|{error, Reason} //监听端口

Options: 

{active, true}:创建一个主动套接字;当数据到达时候,控制进程会发送{tcp, Socket, Data}消息, 无法控制客户端的发送量,有导致服务器来不及处理消息的风险。

{active, false}: 创建一个被动套接字;控制进程必须调用gen_tcp:recv(Socket, N)来接收来自于套接字的数据,可以控制客户端的发送量。

{active, once}: 创建一个主动套接字, 但是只接收一条消息,如果需要接收下一条消息,必须再激活它。

inet:setopts(Socket, Options) -> ok|{error, posix()} //设置socket的一些属性

inet:peername(Socket) -> {ok, {IP_Address, Port}}| {error, Why} //返回的是客户端的IP地址和端口号,{N1,N2,N3,N4} 代表IPV4,{K1,K2,K3,K4,K5,K6,K7,K8}代表IPV6。

gen_tcp:accept(ListenSocket) -> {ok, Socket}|{error,Reason}  //接收来自客户端的socket链接

gen_tcp:connect(Address, Port, Options) -> {ok, Socket}|{error, Reason}  // 连接socket服务器

gen_tcp:send(Socket, Packet) -> ok | {error, Reason}  // 发送数据

gen_tcp:close(Socket) -> ok   // 关闭Socket

gen_tcp:shutdown(Socket, How) -> ok|{error, Reason}  // 关闭socket

 

构建一个简易的Tcp Socket通讯

1 -module(tcp_socket1).

2 -compile(export_all).

3

4 start_server() ->

5 start_server(6000).

6

7 start_server(Port) ->

8 {ok, ListenSocket} = gen_tcp:listen(Port, [binary,{packet, 0}, {active, true}]),

9 io:format("Server is running ....."),

10 par_connect(ListenSocket).

11

12 par_connect(Listen) ->

13 {ok, Socket} = gen_tcp:accept(Listen),

14 spawn(fun() -> par_connect(Listen) end),

15 loop(Socket).

16

17 loop(Socket) ->

18 receive

19 {tcp, Socket, Data} ->

20 io:format("Server receive binary:~p~n", [Data]),

21 RecStr = binary_to_term(Data),

22 io:format("Server receive binary_to_term:~p~n", [RecStr]),

23 gen_tcp:send(Socket,term_to_binary(RecStr)),

24 io:format("Server send to client binary:~p~n", [term_to_binary(RecStr)]),

25 loop(Socket);

26 {tcp_closed, Socket} ->

27 io:format("Client socket closed")

28 end.

29

30 start_client() ->

31 start_client("localhost", 6000).

32

33 start_client(Address, Port) ->

34 {ok, Socket} = gen_tcp:connect(Address, Port, [binary, {packet, 0}, {active, true}]),

35 ok = gen_tcp:send(Socket, term_to_binary("Nice to meeet you!")),

36 receive

37 {tcp, Socket, Data} ->

38 io:format("Client receive binary:~p~n", [Data]),

39 RecStr = binary_to_term(Data),

40 io:format("Cleint receive binary_to_term:~p~n", [RecStr]),

41 gen_tcp:close(Socket)

42 end.

43

打开两个客户端分别运行服务器和客户端。

服务器窗口显示的信息:

Eshell V5.10.4 (abort with ^G)

1> c(tcp_socket1).

{ok,tcp_socket1}

2> tcp_socket1:start_server().

Server is running .....Server receive binary:<<131,107,0,18,78,105,99,101,32,116,111,32,109,101,101,

101,116,32,121,111,117,33>>

Server receive binary_to_term:"Nice to meeet you!"

Server send to client binary:<<131,107,0,18,78,105,99,101,32,116,111,32,109,

101,101,101,116,32,121,111,117,33>>

Client socket closedok

Server receive binary:<<131,107,0,18,78,105,99,101,32,116,111,32,109,101,101,

101,116,32,121,111,117,33>>

Server receive binary_to_term:"Nice to meeet you!"

Server send to client binary:<<131,107,0,18,78,105,99,101,32,116,111,32,109,

101,101,101,116,32,121,111,117,33>>

Client socket closedServer receive binary:<<131,107,0,18,78,105,99,101,32,116,111,32,109,101,101,

101,116,32,121,111,117,33>>

Server receive binary_to_term:"Nice to meeet you!"

Server send to client binary:<<131,107,0,18,78,105,99,101,32,116,111,32,109,

101,101,101,116,32,121,111,117,33>>

Client socket closed3>

客户端窗口显示的信息:

4> tcp_socket1:start_client().

Client receive binary:<<131,107,0,18,78,105,99,101,32,116,111,32,109,101,101,

101,116,32,121,111,117,33>>

Cleint receive binary_to_term:"Nice to meeet you!"

ok

5> tcp_socket1:start_client().

Client receive binary:<<131,107,0,18,78,105,99,101,32,116,111,32,109,101,101,

101,116,32,121,111,117,33>>

Cleint receive binary_to_term:"Nice to meeet you!"

ok

6> tcp_socket1:start_client().

Client receive binary:<<131,107,0,18,78,105,99,101,32,116,111,32,109,101,101,

101,116,32,121,111,117,33>>

Cleint receive binary_to_term:"Nice to meeet you!"

ok

7>

 


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