tcp_sync_server and tcp_sync_client

#include <iostream>

#include <fstream>

#include <sstream>

#include <boost/asio.hpp>

using namespace std;

using boost::asio::ip::tcp;

const char* serviceList =  "\n\t       Services\n"

"\t**************************\n"

"\t[1] Get current time.\n"

"\t[2] Who's online.\n"

"\t[3] Get system info.\n"

"\t**************************\n\n"

"Please pick a service[1-3]: ";

ifstream fin;

void getResult(const string& cmdPrefix, const char* outputFile,

string& res) {

// cmd == "w > who"

string cmd(cmdPrefix + outputFile);

system(cmd.c_str());//将字符串解析为系统命令，然后执行

fin.open(outputFile);//存在打开文件，否则创建

if (fin) {  ostringstream os; os << fin.rdbuf(); res = os.str();

}

if (fin.is_open()) { fin.close();     }

}

string getServiceContent(const int& select) {

string res;

switch (select) { //time(0)获取当前时间，ctime将时间转换成字

符串。      case 1: {    time_t t = time(0); res = ctime(&t);  break;

}      case 2: getResult("w > ", "who", res);    break;   case 3: getResult("uname -a > ", "uname", res); break;

default:  res = "Sorry, no such service.\n";  break;     }

return res; }

int main() {     try {   boost::asio::io_service io_service; // #1

tcp::acceptor acceptor(io_service, tcp::endpoint(tcp::v4     //tcp::endpoint(端点)由ip地址，端口号，协议版本组成。

(), 8868)); // #2    for (;;) {   tcp::socket socket(io_service); // #3   /不断创建socket对象，并且与acceptor进行关联

acceptor.accept(socket); // #4

// 1, send service list to client

boost::system::error_code ignored_error;

boost::asio::write(socket, boost::asio::buffer(serviceList),     //buffer相当于显示器的一个缓冲，临时存储数据的一个容器

boost::asio::transfer_all(), ignored_error);  //自我感觉read和write是一个固定套路

// 2, receive selection from client              char selection[20];

size_t n = socket.read_some(boost::asio::buffer(selection),

ignored_error);             // 3, send response

string response = getServiceContent(atoi(selection));

boost::asio::write(socket, boost::asio::buffer(response),

boost::asio::transfer_all(), ignored_error);

} // #6     } catch (std::exception& e) {

std::cerr << e.what() << std::endl;     }

return 0; }

************************************************************************

/*  * tcp_sync_client.cpp  *  *  Created on: 2010-3-16 上午11:47:12  *      Author: kwarph  *         Web: http://www.xuanyuan-soft.cn  *        Mail: kwarph@gmail.com  */

#include <iostream>

#include <boost/asio.hpp>

using namespace std;

using boost::asio::ip::tcp;

int main(int argc, char* argv[]) {

try {         // 1, 创建io_service对象

boost::asio::io_service io_service;

// 2, 创建resolver对象关联到io_service对象

tcp::resolver resolver(io_service);

// 3, 创建一个查询对象

tcp::resolver::query query("localhost", "8868");

// 4, 用resolver对象和查询对象获取可用服务器地址

tcp::resolver::iterator endpoint_iterator = resolver.resolve(query); //把用resolve解析query的即localhost首地址给endpoint_iterator      tcp::resolver::iterator end;

//iterator就是endpoint的指针

// 5, 创建tcp::socket对象，关联到io_service

tcp::socket socket(io_service);

// 6, socket对象发起到服务器端的同步连接操作

boost::system::error_code error = boost::asio::error::host_not_found;

while (error && endpoint_iterator != end) {             socket.close();

socket.connect(*endpoint_iterator++, error);         }

if (error) // 如果没有一个地址能连接成功，则抛出异常

throw boost::system::system_error(error);

// 7, 一系列 同步read()和write()

char buf[512];

//1. receive service list from server

//        size_t len = socket.read_some(boost::asio::buffer(buf), error);         //

　　 size_t len = socket.receive(boost::asio::buffer(buf), 0, error);

//2.confirm size of info with server//进行read操作时，先socket.read_some r然后才是asio::read. write则相反，需先asio::write,再socket.write_some,b并且还要socket.send

size_t len = boost::asio::read(socket, boost::asio::buffer(buf), boost::asio::transfer_at_least(1), error);//asio读写时的参数更多

buf[len] = '\0';         cout << buf;

string selection;         cin >> selection;

//3. send selection to server //

boost::asio::write(socket, boost::asio::buffer(selection), //

boost::asio::transfer_all(), error);

//        socket.write_some(boost::asio::buffer(selection,selection.size()), error);

socket.send(boost::asio::buffer(selection,selection.size()),0, error);

//4. receive response from server

len = socket.read_some(boost::asio::buffer(buf), error);

buf[len] = '\0';          cout << buf;     }  catch (std::exception& e) {

std::cerr << e.what() << std::endl;     }

return 0; }