iOS WebSocket长链接的实现方法

websocket

websocket 是 html5 一种新的协议。它实现了浏览器与服务器全双工通信，能更好的节省服务器资源和带宽并达到实时通讯，它建立在 tcp 之上，同 http 一样通过 tcp 来传输数据，但是它和 http 最大不同是：websocket 是一种双向通信协议.

由于项目需要创建一个聊天室,需要通过长链接,和后台保持通讯,进行聊天,并且实时进行热点消息的推送.

目前facebook的socketrocket应该是目前最好的关于socketrocket使用的框架了.而且简单易用.

使用

一般一个项目在启动后的某个时机会启动创建一个长链接,如果需要多个就多次创建.如果只要一个就可以封装为一个单例,全局使用.

可以使用podpod管理库, 在podfile中加入

pod 'socketrocket'

在使用命令行工具cd到当前工程 安装

pod install

导入头文件后即可使用.

为求稳定,我的做法是copy的facebook里socketrocket库到项目里. --> socketrocket地址

1.首先创建一个名为 websocketmanager 的单例类,

+(instancetype)shared;

2.创建一个枚举,分别表示websocket的链接状态

typedef ns_enum(nsuinteger,websocketconnecttype){
  websocketdefault = 0,  //初始状态,未连接,不需要重新连接
  websocketconnect,    //已连接
  websocketdisconnect  //连接后断开,需要重新连接
};

3.创建连接

//建立长连接
- (void)connectserver;

4.处理连接成功的结果;

-(void)websocketdidopen:(rmwebsocket *)websocket; //连接成功回调

5.处理连接失败的结果

- (void)websocket:(srwebsocket *)websocket didfailwitherror:(nserror *)error;//连接失败回调

6.接收消息

///接收消息回调,需要提前和后台约定好消息格式.
- (void)websocket:(srwebsocket *)websocket didreceivemessagewithstring:(nonnull nsstring *)string

7.关闭连接

- (void)websocket:(srwebsocket *)websocket didclosewithcode:(nsinteger)code reason:(nsstring *)reason wasclean:(bool)wasclean;///关闭连接回调的代理

8.为保持长链接的连接状态,需要定时向后台发送消息,就是俗称的:心跳包.

需要创建一个定时器,固定时间发送消息.

9.链接断开情况处理:

首先判断是否是主动断开,如果是主动断开就不作处理.

如果不是主动断开链接,需要做重新连接的逻辑.

具体代码如下:

websocketmanager.h 中的代码

#import 
<foundation foundation="" h="">
 
#import "rmwebsocket.h"
typedef ns_enum(nsuinteger,websocketconnecttype){
  websocketdefault = 0, //初始状态,未连接
  websocketconnect,   //已连接
  websocketdisconnect  //连接后断开
};
@class websocketmanager;
@protocol websocketmanagerdelegate 
 <nsobject>
 
- (void)websocketmanagerdidreceivemessagewithstring:(nsstring *)string;
@end
ns_assume_nonnull_begin
@interface websocketmanager : nsobject
@property (nonatomic, strong) rmwebsocket *websocket;
@property(nonatomic,weak) id
 <websocketmanagerdelegate nbsp="">
  delegate;
@property (nonatomic, assign)  bool isconnect; //是否连接
@property (nonatomic, assign)  websocketconnecttype connecttype;
+(instancetype)shared;
- (void)connectserver;//建立长连接
- (void)reconnectserver;//重新连接
- (void)rmwebsocketclose;//关闭长连接
- (void)senddatatoserver:(nsstring *)data;//发送数据给服务器
@end
ns_assume_nonnull_end
 </websocketmanagerdelegate>
 </nsobject>
</foundation>

websocketmanager.m 中的代码

#import "websocketmanager.h"
@interface websocketmanager ()
<rmwebsocketdelegate>
 
@property (nonatomic, strong) nstimer *heartbeattimer; //心跳定时器
@property (nonatomic, strong) nstimer *networktestingtimer; //没有网络的时候检测网络定时器
@property (nonatomic, assign) nstimeinterval reconnecttime; //重连时间
@property (nonatomic, strong) nsmutablearray *senddataarray; //存储要发送给服务端的数据
@property (nonatomic, assign) bool isactivelyclose;  //用于判断是否主动关闭长连接，如果是主动断开连接，连接失败的代理中，就不用执行 重新连接方法
@end
@implementation websocketmanager
+(instancetype)shared{
  static websocketmanager *_instance = nil;
  static dispatch_once_t oncetoken;
  dispatch_once(&oncetoken, ^{
    _instance = [[self alloc]init];
  });
  return _instance;
}
- (instancetype)init
{
  self = [super init];
  if(self){
    self.reconnecttime = 0;
    self.isactivelyclose = no;
    
    self.senddataarray = [[nsmutablearray alloc] init];
  }
  return self;
}
//建立长连接
- (void)connectserver{
  self.isactivelyclose = no;
  
  self.websocket.delegate = nil;
  [self.websocket close];
  _websocket = nil;
//  self.websocket = [[rmwebsocket alloc] initwithurl:[nsurl urlwithstring:@"https://dev-im-gateway.runxsports.com/ws/token=88888888"]];
  self.websocket = [[rmwebsocket alloc] initwithurl:[nsurl urlwithstring:@"ws://chat.workerman.net:7272"]];
  self.websocket.delegate = self;
  [self.websocket open];
}
- (void)sendping:(id)sender{
  [self.websocket sendping:nil error:null];
}
#pragma mark --------------------------------------------------
#pragma mark - socket delegate
///开始连接
-(void)websocketdidopen:(rmwebsocket *)websocket{
  
  nslog(@"socket 开始连接");
  self.isconnect = yes;
  self.connecttype = websocketconnect;
  [self initheartbeat];///开始心跳
  
}
///连接失败
-(void)websocket:(rmwebsocket *)websocket didfailwitherror:(nserror *)error{
  nslog(@"连接失败");
  self.isconnect = no;
  self.connecttype = websocketdisconnect;
  dlog(@"连接失败，这里可以实现掉线自动重连，要注意以下几点");
  dlog(@"1.判断当前网络环境，如果断网了就不要连了，等待网络到来，在发起重连");
  dlog(@"3.连接次数限制，如果连接失败了，重试10次左右就可以了");
  
  //判断网络环境
  if (afnetworkreachabilitymanager.sharedmanager.networkreachabilitystatus == afnetworkreachabilitystatusnotreachable){ //没有网络
  
    [self nonetworkstarttestingtimer];//开启网络检测定时器
  }else{ //有网络
  
    [self reconnectserver];//连接失败就重连
  }
}
///接收消息
-(void)websocket:(rmwebsocket *)websocket didreceivemessagewithstring:(nsstring *)string{
  
  nslog(@"接收消息---- %@",string);
  if ([self.delegate respondstoselector:@selector(websocketmanagerdidreceivemessagewithstring:)]) {
    [self.delegate websocketmanagerdidreceivemessagewithstring:string];
  }
}
///关闭连接
-(void)websocket:(rmwebsocket *)websocket didclosewithcode:(nsinteger)code reason:(nsstring *)reason wasclean:(bool)wasclean{
  
  self.isconnect = no;
  if(self.isactivelyclose){
    self.connecttype = websocketdefault;
    return;
  }else{
    self.connecttype = websocketdisconnect;
  }
  
  dlog(@"被关闭连接，code:%ld,reason:%@,wasclean:%d",code,reason,wasclean);
  
  [self destoryheartbeat]; //断开连接时销毁心跳
  
  //判断网络环境
  if (afnetworkreachabilitymanager.sharedmanager.networkreachabilitystatus == afnetworkreachabilitystatusnotreachable){ //没有网络
    [self nonetworkstarttestingtimer];//开启网络检测
  }else{ //有网络
    nslog(@"关闭连接");
    _websocket = nil;
    [self reconnectserver];//连接失败就重连
  }
}
///ping
-(void)websocket:(rmwebsocket *)websocket didreceivepong:(nsdata *)pongdata{
  nslog(@"接受pong数据--> %@",pongdata);
}
#pragma mark - nstimer
//初始化心跳
- (void)initheartbeat{
  //心跳没有被关闭
  if(self.heartbeattimer) {
    return;
  }
  [self destoryheartbeat];
  dispatch_main_async_safe(^{
    self.heartbeattimer = [nstimer timerwithtimeinterval:10 target:self selector:@selector(senderheartbeat) userinfo:nil repeats:true];
    [[nsrunloop currentrunloop]addtimer:self.heartbeattimer formode:nsrunloopcommonmodes];
  })
  
}
//重新连接
- (void)reconnectserver{
  if(self.websocket.readystate == rm_open){
    return;
  }
  
  if(self.reconnecttime > 1024){ //重连10次 2^10 = 1024
    self.reconnecttime = 0;
    return;
  }
  
  ws(weakself);
  dispatch_after(dispatch_time(dispatch_time_now, (int64_t)(self.reconnecttime *nsec_per_sec)), dispatch_get_main_queue(), ^{
    
    if(weakself.websocket.readystate == rm_open && weakself.websocket.readystate == rm_connecting) {
      return;
    }
    
    [weakself connectserver];
    //    cthlog(@"正在重连......");
    
    if(weakself.reconnecttime == 0){ //重连时间2的指数级增长
      weakself.reconnecttime = 2;
    }else{
      weakself.reconnecttime *= 2;
    }
  });
  
}
//发送心跳
- (void)senderheartbeat{
  //和服务端约定好发送什么作为心跳标识，尽可能的减小心跳包大小
  ws(weakself);
  dispatch_main_async_safe(^{
    if(weakself.websocket.readystate == rm_open){
      [weakself sendping:nil];
    }
  });
}
//没有网络的时候开始定时 -- 用于网络检测
- (void)nonetworkstarttestingtimer{
  ws(weakself);
  dispatch_main_async_safe(^{
    weakself.networktestingtimer = [nstimer scheduledtimerwithtimeinterval:1.0 target:weakself selector:@selector(nonetworkstarttesting) userinfo:nil repeats:yes];
    [[nsrunloop currentrunloop] addtimer:weakself.networktestingtimer formode:nsdefaultrunloopmode];
  });
}
//定时检测网络
- (void)nonetworkstarttesting{
  //有网络
  if(afnetworkreachabilitymanager.sharedmanager.networkreachabilitystatus != afnetworkreachabilitystatusnotreachable)
  {
    //关闭网络检测定时器
    [self destorynetworkstarttesting];
    //开始重连
    [self reconnectserver];
  }
}
//取消网络检测
- (void)destorynetworkstarttesting{
  ws(weakself);
  dispatch_main_async_safe(^{
    if(weakself.networktestingtimer)
    {
      [weakself.networktestingtimer invalidate];
      weakself.networktestingtimer = nil;
    }
  });
}
//取消心跳
- (void)destoryheartbeat{
  ws(weakself);
  dispatch_main_async_safe(^{
    if(weakself.heartbeattimer)
    {
      [weakself.heartbeattimer invalidate];
      weakself.heartbeattimer = nil;
    }
  });
}
//关闭长连接
- (void)rmwebsocketclose{
  self.isactivelyclose = yes;
  self.isconnect = no;
  self.connecttype = websocketdefault;
  if(self.websocket)
  {
    [self.websocket close];
    _websocket = nil;
  }
  
  //关闭心跳定时器
  [self destoryheartbeat];
  
  //关闭网络检测定时器
  [self destorynetworkstarttesting];
}
//发送数据给服务器
- (void)senddatatoserver:(nsstring *)data{
  [self.senddataarray addobject:data];
  
  //[_websocket sendstring:data error:null];
  
  //没有网络
  if (afnetworkreachabilitymanager.sharedmanager.networkreachabilitystatus == afnetworkreachabilitystatusnotreachable)
  {
    //开启网络检测定时器
    [self nonetworkstarttestingtimer];
  }
  else //有网络
  {
    if(self.websocket != nil)
    {
      // 只有长连接open开启状态才能调 send 方法，不然会crash
      if(self.websocket.readystate == rm_open)
      {
//        if (self.senddataarray.count > 0)
//        {
//          nsstring *data = self.senddataarray[0];
          [_websocket sendstring:data error:null]; //发送数据
//          [self.senddataarray removeobjectatindex:0];
//
//        }
      }
      else if (self.websocket.readystate == rm_connecting) //正在连接
      {
        dlog(@"正在连接中，重连后会去自动同步数据");
      }
      else if (self.websocket.readystate == rm_closing || self.websocket.readystate == rm_closed) //断开连接
      {
        //调用 reconnectserver 方法重连,连接成功后 继续发送数据
        [self reconnectserver];
      }
    }
    else
    {
      [self connectserver]; //连接服务器
    }
  }
}
@end
</rmwebsocketdelegate>

注意点

我们在发送消息之前,也就是调用  senderheartbeat/ senddatatoserver:方法之前，一定要判断当前scoket是否连接，如果不是连接状态，程序则会crash。

ios手机屏幕息屏或者回主页的时候有可能会造成链接断开,我这边的处理是在回到屏幕的时候,判断状态,如果已经断开,就重新连接.

在 appdelegate 中:

- (void)applicationdidbecomeactive:(uiapplication *)application {
  // restart any tasks that were paused (or not yet started) while the application was inactive. if the application was previously in the background, optionally refresh the user interface.
  if ([websocketmanager shared].connecttype == websocketdisconnect) {
    [[websocketmanager shared] connectserver];    
  }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。