Linux C++ 实现简单的广播服务

简单的广播服务：就是客户端可以关注某个话题，当某个话题有信息发布了之后，关注了该话题的客户端就可以收到该信息。

服务端主要是通过epoll来处理所有连接的文件描述符，某个文件描述符有事件产生就处理。

客户端有两个，一个是关注话题的，一个是发布话题信息的。

关注话题的客户端通过TCP连接，首先发送关注的话题，再等待话题信息的到来。

发布话题信息的客户端通过UDP将某个话题信息发送到服务端，服务端再转发给关注了该话题的客户端。

下面的Client.h和Client.cpp主要是管理客户关注的话题以及客户连接的文件描述符。

代码中有注释，都可以看懂的。

Client.h

#ifndef _CLIENT_H_
#define _CLIENT_H_

#include 
#include 
#include 
#include 


using std::vector;
using std::string;

//客户信息类
struct Client
{
    int fd;   //客户连接的sockfd
    vector topic;  //客户关注的话题
};
//客户信息管理类
class Client_Data
{
private:
    vector client;  //客户信息数组
    Client_Data(){}

public:
    ~Client_Data(){}
    static Client_Data* getInstance();        //获取Client_Data对象
    void AddClient(struct Client cli);        //新的客户连接，添加客户信息
    void RemClient(int sockfd);               //客户关闭连接，删除客户信息
    void AddTopic(int fd, vector topic);      //添加用户关注的话题
    vector FindFdOfTopic(string topic);  //根据话题查找哪些客户关注了該话题
    void printClient();                       //打印Client,测试用
};

#endif

Client.cpp

#include "Client.h"


//获取管理客户信息的类，单例
Client_Data* Client_Data::getInstance()
{
    static Client_Data *Cdata = NULL;
    if(Cdata == NULL)
	Cdata = new Client_Data();
    return Cdata;
}
/*
客户信息管理类由主线程调用，不需要锁
*/
//添加客户信息
void Client_Data::AddClient(struct Client cli)
{
    client.push_back(cli);
}
//删除客户信息
void Client_Data::RemClient(int sockfd)
{
    vector::iterator it;
    for(it = client.begin(); it != client.end(); ++it)
    {
	if(it->fd == sockfd)
	{
	    client.erase(it);
	    break;
	}
    }
}

//向客户添加他所关注的话题
void Client_Data::AddTopic(int fd, vector topic)
{
    vector::iterator it;
    for(it = client.begin(); it != client.end(); ++it)
    {
	if(it->fd == fd)
	{
	    it->topic = topic;
	    break;
	}
    }
}

//根据话题获取客户
vector Client_Data::FindFdOfTopic(string topic)
{
    vector ans;
    vector::iterator it;
    vector::iterator sit;
    for(it = client.begin(); it != client.end(); ++it)
    {
	for(sit = it->topic.begin(); sit != it->topic.end(); ++sit)
	{
	   if(*sit == topic)
	   {
	       ans.push_back(it->fd);
	   }
	}
    }
    return ans;
}

void Client_Data::printClient()
{
    vector::iterator it;
    vector::iterator sit;
    for(it = client.begin(); it != client.end(); ++it)
    {
	printf("%d:", it->fd);
	for(sit = it->topic.begin(); sit != it->topic.end(); ++sit)
	{
	   printf(" %s", sit->c_str());
	}
	printf("\n");
    }
}

main函数的cpp文件

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#include "../thread_pool.h"
#include "Client.h"

#define MAXBUFFER 1024
#define MAXLINE 512
#define MAXEVENTNUMBER 50


epoll_event events[MAXEVENTNUMBER];
int epollfd;

class task;

threadpool *pool = NULL;
Client_Data *client = NULL;

//任务类
class task
{
private:
    int fd;   //客户sockfd
    string message;  //发送的消息
public:
    task(int fd, string message);
    ~task();
    void doit();
};
//构造函数
task::task(int f, string mess) : fd(f), message(mess)
{}
//析构函数
task::~task()
{}
//任务执行函数，将消息发送给客户
void task::doit()
{
    const char *p = message.c_str();
    int ret = write(fd, p, strlen(p));
    if(ret < 0)
    {
	printf("write error: %s\n", strerror(errno));
    }
}

//将文件描述符设置成非阻塞模式
int setnonblocking(int fd)
{
    int old_option = fcntl(fd, F_GETFL);
    int new_option = old_option | O_NONBLOCK;
    fcntl(fd, F_SETFL, new_option);
    return old_option;
}
//文件描述符fd添加事件EPOLLIN，并注册到epollfd的epoll内核事件表,默认LT模式
void addfd(int epollfd, int fd)
{
    epoll_event event;
    event.data.fd = fd;
    event.events = EPOLLIN;
    epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &event);
    setnonblocking(fd);
}


void Epoll(int listenfd, int udpfd)
{
    int i, ret, connfd; //连接套接字
    socklen_t len;
    sockaddr_in cliaddr;//客户地址信息
    for( ; ; )
    {
	//获取已经就绪的描述符
	ret = epoll_wait(epollfd, events, MAXEVENTNUMBER, -1);
 	if(ret < 0)
	{//出错处理
	    printf("epoll_wait error: %s\n", strerror(errno));
	    return;
 	}
  	for(i = 0; i < ret; ++i)
	{
	    int fd = events[i].data.fd;
	    if(fd == listenfd)  //新的连接到来
	    {
		len = sizeof(cliaddr);
		connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &len);
	 	char buf[20];
		printf("IP %s conn\n", inet_ntop(AF_INET, 
			&cliaddr.sin_addr, buf, sizeof(buf)));
		Client cli;
		cli.fd = connfd;
		client->AddClient(cli);
		addfd(epollfd, connfd);//添加进epollfd的epoll内核事件表
	    }
	    else if(fd == udpfd)
	    {//udp发送推送话题信息的到来
		char buffer[MAXBUFFER];
		char temp[20], topic[50];
		int index = 0, k = 0;
		memset(buffer, '\0', MAXBUFFER);
		struct sockaddr_in cliaddr;
		socklen_t len = sizeof(cliaddr);
		//接收推送的话题消息
		int ret = recvfrom(udpfd, buffer, MAXBUFFER - 1, 
		0, (struct sockaddr *)&cliaddr, &len);
		if(ret < 0)
		{
		    printf("UDP recvfrom error : %s\n", strerror(errno));
		    continue;
		}
		buffer[ret] = '\0';
		//查看消息头，判断是否为推送话题消息
		//推送消息格式:push#topic#messge
		while(buffer[index] != '#' && buffer[index] != '\0')
		{
		    temp[k] = buffer[index];
		    ++k; ++index;
		}
		++index;
		temp[k] = '\0';
		if(!strcmp(temp, "push"))  //推送话题消息
		{
		    k = 0;
		    //获取话题
		    while(buffer[index] != '#' && buffer[index] != '\0')
		    {
			topic[k] = buffer[index];
			++k; ++index;
		    }
		    ++index;
		    topic[k] = '\0';
		    string str(topic);
		    //查找关注了该话题的客户
		    vector fds = client->FindFdOfTopic(str);
		    char *p = buffer + index;
		    //printf("fds %d\n", (int)fds.size());
		    //client->printClient();
		    sprintf(buffer, "%s: %s", topic, p); //在消息头添加话题信息
		    string mess(buffer); //最后部分为推送的消息
		    //printf("%s\n", mess.c_str());
		    vector::iterator it;
		    //向关注了该话题的客户推送消息
		    for(it = fds.begin(); it != fds.end(); ++it)
		    {
			task *ta = new task(*it, mess);
			//printf("%d \n", *it);
			pool->append_task(ta);
		    }
			//回复发布话题消息成功
		    sendto(udpfd, "push success", 12, 0, 
			(struct sockaddr *)&cliaddr, len);
		}
		else
		{//回复发布话题消息失败
		    sendto(udpfd, "push error", 10, 0, 
			(struct sockaddr *)&cliaddr, len);
		}
	    }
	    else if(events[i].events & EPOLLIN)
	    {//LT模式，有数据可读就触发
		char buffer[MAXBUFFER];

		memset(buffer, '\0', sizeof(buffer));
		int getByte = read(fd, buffer, MAXBUFFER - 1);  //读取消息
		buffer[getByte] = '\0';
		if(getByte < 0)
		{
		    printf("read buffer error : %s\n", strerror(errno));
		    continue;
		}
		else if(getByte == 0) //客户关闭连接。删除客户信息
		{
		    close(fd);
		    client->RemClient(fd);
		    break;
		}
		else
		{//关注话题消息格式为: get#topic#topic#...#topic#
		    char temp[20], topic[50];
		    int index = 0, k = 0;
		    //查看消息头，判断是否关注话题
		     while(buffer[index] != '#' && buffer[index] != '\0')
		    {
			temp[k] = buffer[index];
			++k; ++index;
		    }
		    ++index;
		    temp[k] = '\0';
		    if(!strcmp(temp, "get")) //关注话题
		    {
			vector top; //话题的数组
			while(buffer[index] != '\0')
			{
			    k = 0;
			    while(buffer[index] != '#') //获取每个话题
			    {
				topic[k] = buffer[index];
				++k; ++index;
			    }
			    ++index;
			    topic[k] = '\0';
			    string s_topic(topic);
			    top.push_back(s_topic);
			}
			client->AddTopic(fd, top);//为该客户添加他所关注的话题
			string mess("follow success"); //回复成功关注消息
			task *ta = new task(fd, mess);
			pool->append_task(ta);
		    }
		    else  //接收消息头部信息不匹配
		    {
			string mess("follow error"); //回复关注失败消息
			task *ta = new task(fd, mess);
			pool->append_task(ta);
		    }
		}	
	    }
	    else
	    {
		printf("Other things happened\n");
	    }
	}
    }
}


int main(int argc, char *argv[])
{
    if(argc != 2)
    {
	printf("usage: %s port", argv[0]);
	return 1;
    }
    //监听套接字，UDP连接套接字
    int listenfd, udpfd;
    struct sockaddr_in seraddr, udpaddr;
    int port = atoi(argv[1]);  //端口

    //初始化服务端的sockaddr_in
    bzero(&seraddr, sizeof(seraddr));
    seraddr.sin_family = AF_INET;
    seraddr.sin_port = htons(port);
    seraddr.sin_addr.s_addr = htonl(INADDR_ANY);

    //创建监听套接字
    listenfd = socket(AF_INET, SOCK_STREAM, 0);
    if(listenfd < 0)
    {
	printf("socket error: %s\n", strerror(errno));
	return 1;
    }
    //绑定
    int ret = bind(listenfd, (struct sockaddr *)&seraddr, sizeof(seraddr));
    if(ret < 0)
    {
	printf("bind error: %s\n", strerror(errno));
	return 1;
    }
    //监听
    listen(listenfd, 10);
    
    //创建udp套接字
    bzero(&udpaddr, sizeof(udpaddr));
    udpaddr.sin_family = AF_INET;
    udpaddr.sin_port = htons(port);
    udpaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    udpfd = socket(AF_INET, SOCK_DGRAM, 0);
    if(udpfd < 0)
    {
	printf("UDP socket error: %s\n", strerror(errno));
	return 1;
    }
    ret = bind(udpfd, (struct sockaddr *)&udpaddr, sizeof(udpaddr));
    if(ret < 0)
    {
	printf("UDP bind error: %s\n", strerror(errno));
	return 1;
    }

    //创建epoll的文件描述符
    epollfd = epoll_create(20);
    if(epollfd < 0)
    {
	printf("epollfd create error: %s\n", strerror(errno));
	return 1;
    }
    addfd(epollfd, listenfd);
    addfd(epollfd, udpfd);
    //创建客户管理对象
    client = Client_Data::getInstance();
    
    //开启线程池，用于推送话题消息。
    pool = new threadpool(5, 10);
    pool->start();
    
    //epoll
    Epoll(listenfd, udpfd);
    return 0;
}

关注话题的客户端代码：

很简单，首先发送一个关注的信息，例如：get#topic#topic#...#topic#

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define MAXBUFFER 2048
#define MAXLINE 1024

int main(int argc, char *argv[])
{
    if(argc < 4)
    {
	printf("usage: %s IP port topic...\n", argv[0]);
	return 1;
    }
    char buffer[MAXBUFFER];
    char message[MAXLINE];
    int sockfd, i;
    size_t size;
    struct sockaddr_in seraddr;
    int port = atoi(argv[2]);    

    bzero(&seraddr, sizeof(seraddr));
    seraddr.sin_family = AF_INET;
    seraddr.sin_port = htons(port);
    inet_pton(AF_INET, argv[1], &seraddr.sin_addr);

    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if(sockfd < 0)
    {
	printf("socket error: %s\n", strerror(errno));
 	return 1;
    }

    connect(sockfd, (struct sockaddr *)&seraddr, sizeof(seraddr));
    
    //获取关注话题的消息
    sprintf(buffer, "get#");
    for(i = 3; i < argc; ++i)
    {
	sprintf(buffer, "%s%s#", buffer, argv[i]);
    }
    
    write(sockfd, buffer, strlen(buffer));
    //读取关注是否成功
    size = read(sockfd, message, MAXLINE - 1);
    printf("%s\n", message);
    //等待话题消息
    while(1)
    {
	size = read(sockfd, message, MAXLINE - 1);
	message[size] = '\0';
  	if(size == 0)
	{
	    printf("server close\n");
	    break;
 	}
	else if(size < 0)
	{
	    printf("read error: %s\n", strerror(errno));
	    continue;
	}
	printf("%s\n", message);
    }
    return 0;
}

推送话题信息的代码，很简单的

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define MAXLINE 1024
#define MAXBUFFER 2048

int main(int argc, char *argv[])
{
    if(argc != 3)
    {
	printf("usage: %s IP port\n", argv[0]);
	return 1;
    }
    char topic[50];
    char message[MAXLINE];
    char buffer[MAXBUFFER];
    int sockfd;
    int port = atoi(argv[2]);
    struct sockaddr_in seraddr;

    bzero(&seraddr, sizeof(seraddr));
    seraddr.sin_family = AF_INET;
    seraddr.sin_port = htons(port);
    inet_pton(AF_INET, argv[1], &seraddr.sin_addr);
    
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    printf("Input the topic: ");
    scanf("%s", topic);
    printf("Input the message: ");
    getchar();
    scanf("%[^\n]", message);

    sprintf(buffer, "push#%s#%s", topic, message);
    printf("buffer:%s\n", buffer);

    sendto(sockfd, buffer, strlen(buffer), 0, (struct sockaddr *)&seraddr, 
		sizeof(seraddr)); 

    recvfrom(sockfd, message, MAXLINE, 0, NULL, NULL);
    printf("message:%s\n", message);
    close(sockfd);
    return 0;
}

很简单的广播服务，主要是Socket编程。一起学习，一起成长。