iOS 使用 socket 实现即时通信示例（非第三方库）

#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>

@interface clientmodel : nsobject
@property(nonatomic,assign)int clientsocket;
@property(nonatomic,copy)nsstring *clientname;
@end

#import "viewcontroller.h"

#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#import "clientmodel.h"
static int const kmaxconnectcount = 5;

@interface viewcontroller()
@property (weak) iboutlet nstextfield *textfield;
//@property (nonatomic,assign)int client_socket; //客户端socket
@property (unsafe_unretained) iboutlet nstextview *textview;
 @property (nonatomic,strong)nsmutablearray *clientarray;
 @property (nonatomic,strong)nsmutablearray *clientnamearray;
@end

@implementation viewcontroller

- (nsmutablearray *)clientarray {
 if (!_clientarray) {
  _clientarray = [nsmutablearray array];
 }
 return _clientarray;
}
- (nsmutablearray *)clientnamearray {
 if (!_clientnamearray) {
  _clientnamearray = [nsmutablearray array];
 }
 return _clientnamearray;
}

- (void)viewdidload {
 [super viewdidload];
 // do any additional setup after loading the view.
 //创建socket
 int server_socket = socket(af_inet, sock_stream, 0);
 if (server_socket == -1) {
  nslog(@"创建失败");
  [self showlogswithstring:@"socket创建失败"];

 }else{
  //绑定地址和端口
  struct sockaddr_in server_addr;
  server_addr.sin_len = sizeof(struct sockaddr_in);
  server_addr.sin_family = af_inet;
  server_addr.sin_port = htons(1234);
  server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
  bzero(&(server_addr.sin_zero), 8);

  int bind_result = bind(server_socket, (struct sockaddr*)&server_addr, sizeof(server_addr));
  if (bind_result == -1) {
   nslog(@"绑定端口失败");
   [self showlogswithstring:@"绑定端口失败"];

  }else{
   if (listen(server_socket, kmaxconnectcount)==-1) {
    nslog(@"监听失败");
    [self showlogswithstring:@"监听失败"];

   }else{
    for (int i = 0; i < kmaxconnectcount; i++) {
     //接受客户端的链接
     [self acceptclientwithserversocket:server_socket];
    }
   }
  }
 }
}


- (void)setrepresentedobject:(id)representedobject {
 [super setrepresentedobject:representedobject];

 // update the view, if already loaded.
}

//创建线程接受客户端
-(void)acceptclientwithserversocket:(int)server_socket{
 struct sockaddr_in client_address;
 socklen_t address_len;
 dispatch_queue_t queue = dispatch_get_global_queue(dispatch_queue_priority_default, 0);
 dispatch_async(queue, ^{
  //创建新的socket
  while (1) {
   int client_socket = accept(server_socket, (struct sockaddr*)&client_address,&address_len );
   if (client_socket == -1) {
    [self showlogswithstring:@"接受客户端链接失败"];
    nslog(@"接受客户端链接失败");
   }else{
    nsstring *acceptinfo = [nsstring stringwithformat:@"客户端 in,socket:%d",client_socket];
    [self showlogswithstring:acceptinfo];

    //接受客户端数据
    [self recvfromclinetwithsocket:client_socket];
   }
  }
 });
}

//接受客户端数据
- (void)recvfromclinetwithsocket:(int)client_socket{
 while (1) {
  //接受客户端传来的数据
  char buf[1024] = {0};
  long ireturn = recv(client_socket, buf, 1024, 0);
  if (ireturn>0) {
   nslog(@"客户端来消息了");
   nsstring *str = [nsstring stringwithcstring:buf encoding:nsutf8stringencoding];
   [self showlogswithstring:[nsstring stringwithformat:@"客户端来消息了:%@",str]];
   [self checkrecvstr:str andclientsocket:client_socket];
  }else if (ireturn == -1){
   nslog(@"读取消息失败");
   [self showlogswithstring:@"读取消息失败"];
   break;
  }else if (ireturn == 0){
   nslog(@"客户端走了");
   [self showlogswithstring:[nsstring stringwithformat:@"客户端 out socket:%d",client_socket]];
   nsmutablearray *array = [nsmutablearray arraywitharray:self.clientarray];
   for (clientmodel *model in array) {
    if (model.clientsocket == client_socket) {
     [self.clientnamearray removeobject:model.clientname];
     [self.clientarray removeobject:model];
    }
   }

   close(client_socket);

   break;
  }
 }
}

 //检查接受到的字符串
- (void)checkrecvstr:(nsstring*)str andclientsocket:(int)socket{
 if ([str hasprefix:@"name:"]) {
  nsstring *name = [str substringfromindex:5];

  clientmodel *model = [[clientmodel alloc] init];
  model.clientsocket = socket;
  model.clientname = name;


  if (self.clientarray.count > 0) {
   int flag = 999;
   //用户名不能相同
   int i = 0;

   for (clientmodel *client in self.clientarray) {

    //改名
    if (client.clientsocket == socket) {
     nsstring *oldname = self.clientnamearray[i];
     self.clientnamearray[i] = name;
     self.clientarray[i] = model;

     for (clientmodel *oldclient in self.clientarray) {
      [self sendmsg:[nsstring stringwithformat:@"%@ 改名 %@",oldname,name] toclient:oldclient.clientsocket];
      [self showlogswithstring:[nsstring stringwithformat:@"%@ 改名 %@",oldname,name]];
      nsstring *list = [self.clientnamearray componentsjoinedbystring:@","];
      //向客户端推送当前在线列表
      [self sendmsg:[nsstring stringwithformat:@"list:%@",list] toclient:oldclient.clientsocket];
     }

     flag = 2;

    }else{
     if ([client.clientname isequaltostring:model.clientname]) {
      //用户名已存在
      flag = 1;
      break;
     }
    }
    i++;

   }
   if (flag != 1 & flag != 2) {
    [self.clientarray addobject:model];
    [self.clientnamearray addobject:model.clientname];
    //向客户端推送当前在线列表
    for (clientmodel *client in self.clientarray) {
     [self sendmsg:[nsstring stringwithformat:@"%@,上线了",name] toclient:client.clientsocket];
     nsstring *list = [self.clientnamearray componentsjoinedbystring:@","];
     //向客户端推送当前在线列表
     [self sendmsg:[nsstring stringwithformat:@"list:%@",list] toclient:client.clientsocket];
    }

    //给当前客户端发送一条欢迎信息
    nsstring *msg = [nsstring stringwithformat:@"welcome %@ !",name];
    [self sendmsg:msg toclient:socket];
    [self showlogswithstring:msg];

   }else if (flag == 1){
    [self sendmsg:@"注册用户名失败，用户名已经存在，请重新设置用户名" toclient:socket];
    [self showlogswithstring:[nsstring stringwithformat:@"socket %d 注册用户名失败，设置的用户名已经存在",socket]];

    for (clientmodel *model in self.clientarray) {

     [name isequaltostring:model.clientname];
    }



   }
  }else{
   [self.clientarray addobject:model];
   [self.clientnamearray addobject:model.clientname];
   //向客户端推送当前在线列表
   //给当前客户端发送一条欢迎信息
   nsstring *msg = [nsstring stringwithformat:@"welcome %@ !",name];
   [self sendmsg:msg toclient:socket];
   [self showlogswithstring:msg];

   nsstring *list = [self.clientnamearray componentsjoinedbystring:@","];
   //向客户端推送当前在线列表
   [self sendmsg:[nsstring stringwithformat:@"list:%@",list] toclient:socket];

  }

 }
 //给某人发消息
 else if ([str hasprefix:@"to:"]){
  nsrange namerange = [str rangeofstring:@"*"];
  nsstring *name = [str substringwithrange:nsmakerange(3, namerange.location-3)];
  nsstring *content = [str substringfromindex:namerange.location+1];
  nsstring *fromclientname;
  //找出发送者
  for (clientmodel *model in self.clientarray) {
   if (socket == model.clientsocket) {
    fromclientname = model.clientname;
    break;
   }
  }

  //给目标发送信息
  for (clientmodel *model in self.clientarray) {
   if ([name isequaltostring:model.clientname]) {
    nsstring *msg = [nsstring stringwithformat:@"%@ to you\n%@",fromclientname,content];
    [self sendmsg:msg toclient:model.clientsocket];

    [self showlogswithstring:[nsstring stringwithformat:@"%@ 发送给 %@ 内容是：%@",fromclientname,name,content]];
    break;

   }
  }

 }
}

//给客户端发送信息
- (void)sendmsg:(nsstring*)msg toclient:(int)socket{
 char *buf[1024] = {0};
 const char *p1 = (char*)buf;
 p1 = [msg cstringusingencoding:nsutf8stringencoding];
 send(socket, p1, 1024, 0);
}

 //在界面上显示日志
- (void)showlogswithstring:(nsstring*)str {
 dispatch_async(dispatch_get_main_queue(), ^{
  nsstring *newstr = [nsstring stringwithformat:@"\n%@",str];
  self.textview.string = [self.textview.string stringbyappendingstring:newstr];
 });
}

@end

#import "viewcontroller.h"
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
@interface viewcontroller ()<uitableviewdelegate,uitableviewdatasource>
//服务器socket
@property (nonatomic,assign)int server_socket;

//ui
@property (weak, nonatomic) iboutlet uitextfield *usernamefield;
@property (weak, nonatomic) iboutlet uitextview *chatview;
@property (weak, nonatomic) iboutlet uitextfield *msgfield;
@property (weak, nonatomic) iboutlet uilabel *toname;
@property (weak, nonatomic) iboutlet uiview *onlineuserview;
@property (nonatomic,strong)uitableview *onlinetable;

//user列表
@property (nonatomic,strong)nsmutablearray *userarray;

@end

@implementation viewcontroller
- (nsmutablearray *)userarray {
 if (!_userarray) {
  _userarray = [nsmutablearray array];
 }
 return _userarray;
}
- (void)viewdidload {
 [super viewdidload];
 [self.usernamefield becomefirstresponder];
 self.usernamefield.text = @"";
 self.msgfield.text = @"";
 //添加table用户列表
 self.onlinetable = [[uitableview alloc] initwithframe:self.onlineuserview.frame style:uitableviewstyleplain];
 self.onlinetable.delegate = self;
 self.onlinetable.datasource = self;
 [self.view addsubview:self.onlinetable];

 int server_socket = socket(af_inet, sock_stream, 0);
 if (server_socket == -1) {
  nslog(@"创建失败");
 }else{
  //绑定地址和端口
  struct sockaddr_in server_addr;
  server_addr.sin_len = sizeof(struct sockaddr_in);
  server_addr.sin_family = af_inet;
  server_addr.sin_port = htons(1234);
  server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
  bzero(&(server_addr.sin_zero), 8);

  //接受客户端的链接
  dispatch_queue_t queue = dispatch_get_global_queue(dispatch_queue_priority_default, 0);
  dispatch_async(queue, ^{
   //创建新的socket
   int aresult = connect(server_socket, (struct sockaddr*)&server_addr, sizeof(struct sockaddr_in));
   if (aresult == -1) {
    nslog(@"链接失败");
   }else{
    self.server_socket = server_socket;
    [self acceptfromserver];
   }
  });
 }
}

//从服务端接受消息
- (void)acceptfromserver{
 while (1) {
  //接受服务器传来的数据
  char buf[1024];
  long ireturn = recv(self.server_socket, buf, 1024, 0);
  if (ireturn>0) {
   nsstring *str = [nsstring stringwithcstring:buf encoding:nsutf8stringencoding];

   //筛选前缀
   if ([str hasprefix:@"list:"]) {
    nsstring *arraystr = [str substringfromindex:5];
    nsarray *list = [arraystr componentsseparatedbystring:@","];
    self.userarray = [nsmutablearray arraywitharray:list];
    dispatch_async(dispatch_get_main_queue(), ^{
     [self.onlinetable reloaddata];
    });
    nslog(@"当前在线用户列表：%@",arraystr);
   }else{
    //回到主线程 界面上显示内容
    [self showlogswithstring:str];
   }

  }else if (ireturn == -1){
   nslog(@"接受失败-1");
   break;
  }
 }
}

//在界面上显示日志
- (void)showlogswithstring:(nsstring*)str {
 dispatch_async(dispatch_get_main_queue(), ^{
  nsstring *newstr = [nsstring stringwithformat:@"\n%@",str];
  self.chatview.text = [self.chatview.text stringbyappendingstring:newstr];
 });
}

- (void)didreceivememorywarning {
 [super didreceivememorywarning];
 // dispose of any resources that can be recreated.
}

//设置用户名
- (ibaction)clicksetusername:(id)sender {
 nsstring *msg = [nsstring stringwithformat:@"name:%@",self.usernamefield.text] ;
 [self sendmsg:msg];
// [self showlogswithstring:msg];
 [self.msgfield becomefirstresponder];
}

//发送信息
- (ibaction)clicksendmsg:(id)sender {
 if ([self.msgfield.text isequaltostring:@""] || ![self.userarray containsobject:self.usernamefield.text] || [self.toname.text isequaltostring:self.usernamefield.text]) {
  [self showlogswithstring:@"请设置用户名、检查发送对象、消息不能为空"];
  return;
 }
 nsstring *msg = [nsstring stringwithformat:@"to:%@*%@",self.toname.text,self.msgfield.text];
 [self sendmsg:msg];
 nsstring *displaymsg = [nsstring stringwithformat:@"to:%@\n%@",self.toname.text,self.msgfield.text];
 [self showlogswithstring:displaymsg];
 self.msgfield.text = @"";

}

//给客户端发送信息
- (void)sendmsg:(nsstring*)msg {
 char *buf[1024] = {0};
 const char *p1 = (char*)buf;
 p1 = [msg cstringusingencoding:nsutf8stringencoding];
 send(self.server_socket, p1, 1024, 0);
}

#pragma mark - tableviewdelegate & datasource
- (nsinteger)tableview:(uitableview *)tableview numberofrowsinsection:(nsinteger)section{
 return self.userarray.count;
}
- (uitableviewcell *)tableview:(uitableview *)tableview cellforrowatindexpath:(nsindexpath *)indexpath{
 static nsstring *cellid = @"onlinetableviewcellid";
 uitableviewcell *cell = [tableview dequeuereusablecellwithidentifier:cellid];
 if (cell == nil) {
  cell = [[uitableviewcell alloc] initwithstyle:uitableviewcellstyledefault reuseidentifier:cellid];
 }else{
  nslog(@"cell重用了");
 }
 cell.textlabel.text = self.userarray[indexpath.row];
 return cell;
}

//点击cell
- (void)tableview:(uitableview *)tableview didselectrowatindexpath:(nsindexpath *)indexpath{
 self.toname.text = self.userarray[indexpath.row];
 [self.msgfield becomefirstresponder];
}
@end