erlang 实现与 c++ 通讯

erlang 实现与 c++ 通讯

分类： c/c++ erlang/mnesia 2013-10-19 00:20 225人阅读 评论(0) 收藏 举报

erlang socket c++ 通讯

网络通讯常用的有2种：行通讯和包体通讯，也就是常说的文本通讯和二进制通讯。文章分别在两种方式上实现erlang与c++通讯。

一、erlang 与 c++ 行通讯

行通讯是一种文本通讯，格式如“cmd args\n”，比较简单，erlang接收数据也比较简单，可以设置参数{packet, line}，缺点是表示方式单一，很难表示结构数据。

1、erlang 代码（server.erl）：

-module(server).
-export([start/0]).
-define( PORT, 5678).

%% 启动服务并接受客户端的连接
start() ->
  {ok, LSock} = gen_tcp:listen(?PORT, [binary, {packet, line},{active, false}]),
  io:format("socket listen: ~p on ~p ~n",[LSock, ?PORT]),
  accept(LSock).

accept(LSock) ->
  {ok, ASock} = gen_tcp:accept(LSock),
  spawn(fun() -> server_loop(ASock) end),
  accept(LSock).


server_loop(ASock) ->
  case gen_tcp:recv(ASock, 0) of
    {ok, Data} ->
      io:format("recv line data: ~p~n", [Data]),
      gen_tcp:send(ASock, Data),
      server_loop(ASock);
    {error, _} ->
      {ok, recv_error}
    end.

2、c++ 代码（test.cpp）：

#include
#include
#pragma comment(lib, "ws2_32.lib")

int main(int argc, char* argv[])
{
    WSADATA wsaData;
    WSAStartup( MAKEWORD( 2, 2 ), &wsaData );
    SOCKET sc = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0, NULL);
    SOCKADDR_IN addr;
    int len=sizeof(addr);
    addr.sin_family=AF_INET;
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    addr.sin_port = htons(5678);
    connect(sc, (struct sockaddr *)&addr, len);
    char buff[1024];
    memset(buff, 0, 1024);

    char data[] = "aaaaaa\n";

    //发送数据
    printf("send data: %s \n", data);
    send(sc, data, sizeof(data), 0);

    //接收数据
    recv(sc, buff, 1024, 0);
    printf("recv data: %s \n", buff);

    closesocket(sc);
    WSACleanup();
    getchar();
    return 0;
}

二、erlang 与 c++ 包体通讯

包体通讯是二进制通讯，目前主要有结构体，json，asn等等，最简单还可以这样定义：2个字节cmd + 2个字节字符长度 + 字符内容。

下面以结构体包体通讯示例：

1、erlang代码（server.erl）：

-module(server).
-export([start/0]).

-define( UINT, 32/unsigned-little-integer).
-define( INT, 32/signed-little-integer).
-define( USHORT, 16/unsigned-little-integer).
-define( SHORT, 16/signed-little-integer).
-define( UBYTE, 8/unsigned-little-integer).
-define( BYTE, 8/signed-little-integer).

-define( PORT, 5678).

%% 启动服务并接受客户端的连接
start() ->
  {ok, LSock} = gen_tcp:listen(?PORT, [binary, {packet, 0},{active, false}]),
  io:format("socket listen: ~p on ~p ~n",[LSock, ?PORT]),
  accept(LSock).

accept(LSock) ->
  {ok, ASock} = gen_tcp:accept(LSock),
  spawn(fun() -> server_loop(ASock) end),
  accept(LSock).

server_loop(ASock) ->
  case gen_tcp:recv(ASock, 0) of
    {ok, <> = A} ->
      %% _Rest 匹配C++字符串后面的结束符/0
      io:format("recv data: ~p ~p ~p~n", [Len, Cmd, Contain]),
      gen_tcp:send(ASock, A),
      server_loop(ASock);
    {ok, Data} ->
      io:format("recv unformated data: ~p~n", [Data]),
      server_loop(ASock);
    {error, _} ->
      {ok, recv_error}
    end.

2、c++ 代码（test.cpp）：

#include
#include
#pragma comment(lib, "ws2_32.lib")

struct data
{
    unsigned short int len;
    unsigned short int cmd;
    char content[5] ;
};

int main(int argc, char* argv[])
{
    WSADATA wsaData;
    WSAStartup( MAKEWORD( 2, 2 ), &wsaData );
    SOCKET sc = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0, NULL);
    SOCKADDR_IN addr;
    int len=sizeof(addr);
    addr.sin_family=AF_INET;
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    addr.sin_port = htons(5678);
    connect(sc, (struct sockaddr *)&addr, len);
    char buff[1024];
    memset(buff, 0, 1024);

    struct data pdata = {4, 1001, "test"};

    //发送数据
    printf("send data: %d %d %s \n", pdata.len, pdata.cmd, pdata.content);
    send(sc, (char *)&pdata, sizeof(pdata), 0);

    //接收数据
    recv(sc, buff, 1024, 0);
    struct data * pdata_get = (struct data *) buff;
    printf("recv data: %d %s \n", pdata_get->cmd, pdata_get->content);

    closesocket(sc);
    WSACleanup();
    getchar();
    return 0;
}