Socket编程

Socket技术

• 基于网络通信

  • 和http协议相比
    • 具体实现过程
    • 长连接,http是短连接
    • http协议用来做超文本传输
    • socket 什么都可以传

  • iOS

    • GCDAsyncSocket <= CFNetWork <= sys/socket.h
    • NSNetService

  • socket技术

    • tcp/ip和udp
      • tcp/ip,传输控制协议
      • udp,广播类型协议
      • tcp/ip,会更加安全,三次握手的过程是在传输数据前
      • udp,传输速度更快,不可靠性就大,效率慢
    • winsock.h…windows…

`#include <sys/socket.h>    `

`#include <netinet/in.h`


    @implementation AppDelegate
    {
    //服务端的标识
    int server_flag;

    //客户端的标识
    NSMutableArray *clients;

     //计算机地址
          struct sockaddr_in addr;
    }


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
clients = [NSMutableArray array];
int error = -1;
//服务端
//1.创建服务端的标识符(int)
server_flag = socket(AF_INET, SOCK_STREAM, 0);

//2.将服务端的标识符,绑定到一个具体的计算机(ip,port)里 sockaddr_in
addr.sin_port = htons(10000);
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = htonl(INADDR_ANY);

error = bind(server_flag, (struct sockaddr *)&addr, sizeof(addr));

//3.服务端要做好能同时处理多少个链接的事情
error = listen(server_flag, 100);

//4.服务端做好等待客户端链接请求的准备
while (1)
{
    //5.将收到的客户端链接请求生成一个标志位,作为某个客户端的标识
    int client_flag = accept(server_flag, NULL, NULL);

    [clients addObject:@(client_flag)];

    //6.通过客户端的标志位进行消息传输
    char buff[1024];
    int length = recv(client_flag, buff, sizeof(buff), 0);
    buff[length] = '\0';

    printf("client say:%s\n",buff);

    //发送消息...
    char message[] = "Hello, c!\n";
    send([clients.lastObject intValue], message, sizeof(message), 0);

    //7.关闭取消链接的客户端标志位
//        close(client_flag);
}


return YES;
}

客户端

客户端和服务器端配置基本相同,不同的地方已经注释说明

@implementation AppDelegate
{
struct sockaddr_in server;


}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
int error = -1;
//设置客服端表示
int client_flag = socket(AF_INET, SOCK_STREAM, 0);
server.sin_family = AF_INET;
//服务器端端口号
server.sin_port = htons(10000);
//服务器端ip
server.sin_addr.s_addr = inet_addr("172.18.16.37");
//链接服务器
error = connect(client_flag, (struct sockaddr *)&server, sizeof(server));
//发送消息
send(client_flag, "nong sha lei", 80, -1);
char buff[1024];
int length = recv(client_flag, buff, 1024, -1);
buff[length] = '\0';
printf("server say:%s\n",buff);
close(client_flag);


return YES;
}