寫在開始之前

這篇文章的由來是作者以前在看CocoaAsyncSocket一時興起寫的一個即時通訊小demo的介紹梭纹，內(nèi)容包含心跳檢查，粘包斷包處理致份，多用戶并發(fā)調(diào)度变抽，用戶間消息傳送等。最近由于在搞一個sockes5的項目。重新整理了一下CocoaAsyncSocket方面的東西绍载，覺得這個demo還是很意思诡宗，故寫出來和大家分享一下。項目中斷包處理部分借鑒了涂耀輝的《即時通訊下數(shù)據(jù)粘包击儡、斷包處理實(shí)例（基于CocoaAsyncSocket）》一文塔沃。感興趣的同學(xué)也可以看看，還是挺簡單的曙痘。這個項目只作為作者自己學(xué)習(xí)使用芳悲，不做商業(yè)用途立肘，有很多不足和不當(dāng)之處边坤，歡迎大家探討交流。好吧話不多說谅年，切入正題茧痒。

一.關(guān)于CocoaAsyncSocket

這一部分是對CocoaAsyncSocket的一些簡述和方法的一些介紹，已經(jīng)了解的同學(xué)可以直接跳過此部分融蹂。

1.關(guān)于CocoaAsyncSocket

CocoaAsyncSocket是谷歌的開發(fā)者旺订，基于BSD-Socket寫的一個IM框架，它給Mac和iOS提供了易于使用的超燃、強(qiáng)大的異步套接字庫区拳，向上封裝出簡單易用OC接口。省去了我們面向Socket以及數(shù)據(jù)流Stream等繁瑣復(fù)雜的編程意乓。

2.結(jié)構(gòu)

CocoaAsyncSocket中主要包含兩個類:

（1）.GCDAsyncSocket.

用GCD搭建的基于TCP/IP協(xié)議的socket網(wǎng)絡(luò)庫
GCDAsyncSocket is a TCP/IP socket networking library built atop Grand Central Dispatch. -- 引自CocoaAsyncSocket.

（2）.GCDAsyncUdpSocket.

用GCD搭建的基于UDP/IP協(xié)議的socket網(wǎng)絡(luò)庫.
GCDAsyncUdpSocket is a UDP/IP socket networking library built atop Grand Central Dispatch..-- 引自CocoaAsyncSocket.

關(guān)于GCDAsyncUdpSocket暫時不表樱调，有機(jī)會再講。以下主要用到GCDAsyncSocket

3.GCDAsyncSocket下的幾個主要方法的介紹

（1）主動方法

 //連接服務(wù)器host：服務(wù)器地址届良，port：端口笆凌；
 - (BOOL)connectToHost:(NSString*)host onPort:(uint16_t)port error:(NSError **)errPtr
 //發(fā)送消息 timeout：等待時間設(shè)置為-1為一直等待 tag:讀取標(biāo)示；
 - (void)writeData:(NSData *)data withTimeout:(NSTimeInterval)timeout tag:(long)tag
//讀消息timeout：等待時間設(shè)置為-1為一直等待 tag:讀取標(biāo)示士葫。與發(fā)送消息的方法對應(yīng)乞而，要求每發(fā)一條消息，就要調(diào)用一次讀消息慢显，要不然讀取不到爪模。GCDAsyncUdpSocket架構(gòu)要求；
 - (void)readDataWithTimeout:(NSTimeInterval)timeout tag:(long)tag;
 //監(jiān)聽本地端口荚藻。port：要監(jiān)聽的端口屋灌。error：返回的錯誤；
 //- (BOOL)acceptOnPort:(uint16_t)port error:(NSError **)errPtr

（2）代理回調(diào)方法

 //socket成功連接到服務(wù)器調(diào)用
  -(void)socket:(GCDAsyncSocket *)sock didConnectToHost:(NSString *)host port:(uint16_t)port;
 //接受到新的socket連接調(diào)用
  - (void)socket:(GCDAsyncSocket *)sock didAcceptNewSocket:(GCDAsyncSocket *)newSocket;
 //讀取數(shù)據(jù)鞋喇，有數(shù)據(jù)就會調(diào)用
  - (void)readDataWithTimeout:(NSTimeInterval)timeout tag:(long)tag;
 //直到讀到這個長度的數(shù)據(jù)声滥，才會觸發(fā)代理
  - (void)readDataToLength:(NSUInteger)length withTimeout:(NSTimeInterval)timeout tag:(long)tag; 
 //直到讀到data這個邊界，才會觸發(fā)代理 
  - (void)readDataToData:(NSData *)data withTimeout:(NSTimeInterval)timeout tag:(long)tag;
 //有socket斷開連接調(diào)用
  - (void)socketDidDisconnect:(GCDAsyncSocket *)sock withError:(NSError *)err;

好了。我們要用到的方法大概就是這么幾個落塑。方法的解釋已經(jīng)注釋標(biāo)明纽疟，下面開始擼代碼，看下具體實(shí)現(xiàn)憾赁。
???看到這可以休息下污朽，好久沒打這么多字，有點(diǎn)發(fā)昏龙考，接下來就是代碼部分的介紹了??

二.代碼介紹

********代碼在這里??

首先說下demo的大體思路：
看過別人寫過的一些版本蟆肆，大多是開兩個工程，分別模擬服務(wù)器和客戶端晦款。個人覺得這樣比較麻煩炎功，跑起來還得改ip，開兩個設(shè)備沒太大必要缓溅。

我的思路是：做三個單例分別模擬服務(wù)端蛇损，客戶端A，客戶端B坛怪。然后開三個隊列分別處理服務(wù)端淤齐，客戶端A，客戶端B的事務(wù)袜匿。服務(wù)器負(fù)責(zé)接受轉(zhuǎn)發(fā)消息更啄，處理用戶心跳和進(jìn)程調(diào)度。(???當(dāng)然可以寫一個客戶端的公有類居灯，然后實(shí)例化更多的客戶端祭务，給每個客戶端分配隊列和clinetID，這都是OK的穆壕。我們這里為了簡明和方便斷點(diǎn)待牵，直接分開寫了兩個客戶端單利的實(shí)現(xiàn)，但代碼都是一致的喇勋。感興趣的同學(xué)可以按這個思路封裝一個客戶端類創(chuàng)建多個客戶端玩玩??)缨该。
好了言歸正傳，開始貼代碼吧川背。

1.主體部分

屏幕快照 .png

前四個文件為CocoaAsyncSocket的源文件了贰拿。還是比較簡潔，源碼的話熄云，感興趣的同學(xué)也可以看看膨更，后面如果有時間看看能不能做一篇源碼分析。ViewController文件作界面管理缴允，對應(yīng)三個UITextView,分別作ClientA荚守，Sever珍德，ClientB的一些消息展示。Sever矗漾，ClientA锈候，ClientB，看名字就知道分別對應(yīng)服務(wù)器敞贡，客戶端A泵琳，客戶端B，分別作對應(yīng)的事務(wù)處理誊役。

2.客戶端：

.h文件

#import <Foundation/Foundation.h>
typedef void(^clientAMSG)(NSString *msg) ;

@interface ClientA : NSObject
@property(nonatomic,copy)clientAMSG clientAmsg;
+(id)sharClineA;
/*連接服務(wù)器**/
-(BOOL)connect;
/*給B發(fā)消息**/
-(void)sendMSGToB;
-(void)ClientAGetMSG:(clientAMSG)clientAmsg;
@end

h文件里沒什么好說的获列，大家看注釋就好了

.m文件

我先把代碼貼出來，貼這里顯得有點(diǎn)長蛔垢，不要被忽悠了击孩，貼在這里也并不是要各位同學(xué)在這里看的。代碼完全可以先get下來啦桌，在xcode里面看溯壶，只有200來行，其實(shí)結(jié)合注釋還是比較清晰甫男。

#import "ClientA.h"
#import "GCDAsyncSocket.h"
#define HOST @"127.0.0.1"
#define PORT 8088
static dispatch_queue_t CGD_manager_creation_queue() {
    static dispatch_queue_t _CGD_manager_creation_queue;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _CGD_manager_creation_queue = dispatch_queue_create("gcd.mine.queue.ClinetAkey", DISPATCH_QUEUE_CONCURRENT);
    });
    return _CGD_manager_creation_queue;
}
@interface ClientA ()<GCDAsyncSocketDelegate>
{
    NSDictionary *currentPacketHead;
}
@property (nonatomic, strong)NSThread *connectThread;
@property (nonatomic,strong)NSTimer * connectTimer;//心跳定時器
@property (nonatomic,strong)GCDAsyncSocket * clinetSocket;//客戶端Socket
@property (nonatomic,assign)BOOL  isAgain;//控制斷線重連
@end
@implementation ClientA
+(id)sharClineA{
    static ClientA * clinet;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        clinet=[[ClientA alloc]init];
    });
    return clinet;
}
-(void)ClientAGetMSG:(clientAMSG)clientAmsg{
    self.clientAmsg=clientAmsg;
}
/*連接服務(wù)器**/
-(BOOL)connect{
    self.clinetSocket = [[GCDAsyncSocket alloc]initWithDelegate:self delegateQueue:CGD_manager_creation_queue()];
    NSError * error;
    [self.clinetSocket  connectToHost:HOST onPort:PORT error:&error];
    if (!error) {
        return YES;
    }else{
        return NO;
    }
   
}
/*給B發(fā)消息**/
-(void)sendMSGToB{
    NSData *data  =  [@"Hello" dataUsingEncoding:NSUTF8StringEncoding];
    NSData *data1  = [@"I" dataUsingEncoding:NSUTF8StringEncoding];
    NSData *data2  = [@"am" dataUsingEncoding:NSUTF8StringEncoding];
    NSData *data3  = [@"A," dataUsingEncoding:NSUTF8StringEncoding];
    NSData *data4  = [@"nice to meet you!" dataUsingEncoding:NSUTF8StringEncoding];
    
    [self sendData:data :@"txt" toClinet:@"CinentB"];
    [self sendData:data1 :@"txt" toClinet:@"CinentB"];
    [self sendData:data2 :@"txt" toClinet:@"CinentB"];
    [self sendData:data3 :@"txt" toClinet:@"CinentB"];
    [self sendData:data4 :@"txt" toClinet:@"CinentB"];
    
    NSString *filePath = [[NSBundle mainBundle]pathForResource:@"7" ofType:@"jpeg"];
    
    NSData *data5 = [NSData dataWithContentsOfFile:filePath];
    
    [self sendData:data5 :@"img" toClinet:@"CinentB"];

}
/*封裝報文**/
- (void)sendData:(NSData *)data :(NSString *)type toClinet:(NSString *)target;
{
    NSUInteger size = data.length;
    
    NSMutableDictionary *headDic = [NSMutableDictionary dictionary];
    [headDic setObject:type forKey:@"type"];
    [headDic setObject:@"CinentA" forKey:@"CinentID"];
    [headDic setObject:target forKey:@"targetID"];
    [headDic setObject:[NSString stringWithFormat:@"%ld",size] forKey:@"size"];
    NSString *jsonStr = [self dictionaryToJson:headDic];
    NSData *lengthData = [jsonStr dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableData *mData = [NSMutableData dataWithData:lengthData];
    //分界
    [mData appendData:[GCDAsyncSocket CRLFData]];
    
    [mData appendData:data];
    
    
    //第二個參數(shù)，請求超時時間
    [self.clinetSocket writeData:mData withTimeout:-1 tag:0];
    
}
//字典轉(zhuǎn)為Json字符串
- (NSString *)dictionaryToJson:(NSDictionary *)dic
{
    NSError *error = nil;
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dic options:NSJSONWritingPrettyPrinted error:&error];
    return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}

#pragma mark 加入心跳
- (NSThread*)connectThread{
    if (!_connectThread) {
        _connectThread = [[NSThread alloc]initWithTarget:self selector:@selector(threadStart) object:nil];
    }
    return _connectThread;
}
- (void)threadStart{
    @autoreleasepool {
        [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(heartBeat) userInfo:nil repeats:YES];
        [[NSRunLoop currentRunLoop]run];
    }
}
#pragma mark 發(fā)送心跳包
- (void)heartBeat{

        NSData *data  = [@"A心跳" dataUsingEncoding:NSUTF8StringEncoding];
        [self sendData:data :@"heartA" toClinet:@""];
//    [self.clinetSocket writeData:[@"A心跳" dataUsingEncoding:NSUTF8StringEncoding ] withTimeout:-1 tag:0];
    
}


#pragma mark GCDAsyncSocketDelegate
//讀取到數(shù)據(jù)調(diào)用
- (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag{
    //先讀取到當(dāng)前數(shù)據(jù)包頭部信息
    if (!currentPacketHead) {
        currentPacketHead = [NSJSONSerialization
                             JSONObjectWithData:data
                             options:NSJSONReadingMutableContainers
                             error:nil];
        
        
        if (!currentPacketHead) {
            NSLog(@"error：當(dāng)前數(shù)據(jù)包的頭為空");
            
            //斷開這個socket連接或者丟棄這個包的數(shù)據(jù)進(jìn)行下一個包的讀取
            
            //....
            
            return;
        }
        
        NSUInteger packetLength = [currentPacketHead[@"size"] integerValue];
        //讀到數(shù)據(jù)包的大小
        [sock readDataToLength:packetLength withTimeout:-1 tag:0];
        
        return;
    }
    //正式的包處理
    NSUInteger packetLength = [currentPacketHead[@"size"] integerValue];
    //說明數(shù)據(jù)有問題
    if (packetLength <= 0 || data.length != packetLength) {
        NSLog(@"error：當(dāng)前數(shù)據(jù)包數(shù)據(jù)大小不正確");
        return;
    }
    
    NSString *type = currentPacketHead[@"type"];
    NSString * sourceClient=currentPacketHead[@"sourceClient"];
    if ([type isEqualToString:@"img"]) {
        NSLog(@"客戶端A成功收到圖片--來自于%@",sourceClient);
        if (self.clientAmsg) {
            self.clientAmsg([NSString stringWithFormat:@"客戶端A成功收到圖片--來自于%@",sourceClient]);
        }
        
    }else{
        
        NSString *msg = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
        NSLog(@"客戶端A收到消息:%@--來自于%@",msg,sourceClient);
      self.clientAmsg([NSString stringWithFormat:@"客戶端A收到消息:%@--來自于%@",msg,sourceClient]);
    }
    currentPacketHead = nil;
    [sock readDataToData:[GCDAsyncSocket CRLFData] withTimeout:-1 tag:0];
}
//連接到服務(wù)器調(diào)用
- (void)socket:(GCDAsyncSocket *)sock didConnectToHost:(NSString *)host port:(uint16_t)port {
    [self heartBeat];
    NSLog(@"%@",[NSString stringWithFormat:@"%@：連接成功",self.class]);
    if (self.clientAmsg) {
    self.clientAmsg([NSString stringWithFormat:@"%@：連接成功",self.class]);
    }

     [sock readDataToData:[GCDAsyncSocket CRLFData] withTimeout:-1 tag:0];
    //開啟線程發(fā)送心跳
    if (!self.isAgain) {
            [self.connectThread start];
    }

}
//斷開連接調(diào)用
-(void)socketDidDisconnect:(GCDAsyncSocket *)sock withError:(NSError *)err{
    NSLog(@"%@",[NSString stringWithFormat:@"%@：斷開連接(Error:%@)",self.class,err]);
    if (self.clientAmsg) {
         self.clientAmsg([NSString stringWithFormat:@"%@：斷開連接(Error:%@)",self.class,err]);
    }
    
    if (err) {
        //重連
        self.isAgain=YES;
       [self.clinetSocket connectToHost:HOST onPort:PORT error:nil];
    }else{
        self.clinetSocket.delegate=nil;
        self.clinetSocket=nil;
        //斷開
    }
    
}


@end

這里肯定要講一講验烧，不然肯定有同學(xué)要打我了板驳。
講一講思路：
單例方法就沒必要說了。

1.程序入口為-(BOOL)connect方法碍拆，

-(BOOL)connect{
    self.clinetSocket = [[GCDAsyncSocket alloc]initWithDelegate:self delegateQueue:CGD_manager_creation_queue()];
    NSError * error;
    [self.clinetSocket  connectToHost:HOST onPort:PORT error:&error];
    if (!error) {
        return YES;
    }else{
        return NO;
    }
   
}

創(chuàng)建一個GCDAsyncSocket若治，指定代理，代理隊列指定為我們自己通過CGD_manager_creation_queue()方法創(chuàng)建的隊列感混。

static dispatch_queue_t CGD_manager_creation_queue() {
    static dispatch_queue_t _CGD_manager_creation_queue;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _CGD_manager_creation_queue = dispatch_queue_create("gcd.mine.queue.ClinetAkey", DISPATCH_QUEUE_CONCURRENT);
    });
    return _CGD_manager_creation_queue;
}

然后調(diào)用 - (BOOL)connectToHost:(NSString*)host onPort:(uint16_t)port error:(NSError **)errPtr方法端幼，指明服務(wù)器地址端口連接到服務(wù)器。

2.連接到服務(wù)器會觸發(fā)這個代理方法

//連接到服務(wù)器調(diào)用
- (void)socket:(GCDAsyncSocket *)sock didConnectToHost:(NSString *)host port:(uint16_t)port {
    [self heartBeat];
    NSLog(@"%@",[NSString stringWithFormat:@"%@：連接成功",self.class]);
    self.clientAmsg([NSString stringWithFormat:@"%@：連接成功",self.class]);
     [sock readDataToData:[GCDAsyncSocket CRLFData] withTimeout:-1 tag:0];
    //開啟線程發(fā)送心跳
    if (!self.isAgain) {
            [self.connectThread start];
    }

}

在這個方法里加入心跳弧满，連接上第一時間發(fā)送一個心跳包婆跑，目的是為了更新服務(wù)端里的socket的ClientID識別用戶這個后面解釋。

創(chuàng)建心跳和發(fā)送心跳包的方法：

#pragma mark 加入心跳
- (NSThread*)connectThread{
    if (!_connectThread) {
        _connectThread = [[NSThread alloc]initWithTarget:self selector:@selector(threadStart) object:nil];
    }
    return _connectThread;
}
- (void)threadStart{
    @autoreleasepool {
        [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(heartBeat) userInfo:nil repeats:YES];
        [[NSRunLoop currentRunLoop]run];
    }
}
#pragma mark 發(fā)送心跳包
- (void)heartBeat{

        NSData *data  = [@"A心跳" dataUsingEncoding:NSUTF8StringEncoding];
        [self sendData:data :@"heartA" toClinet:@""];
//    [self.clinetSocket writeData:[@"A心跳" dataUsingEncoding:NSUTF8StringEncoding ] withTimeout:-1 tag:0];
    
}

寫數(shù)據(jù)是用
[self.clinetSocket writeData:[@"A心跳" dataUsingEncoding:NSUTF8StringEncoding ] withTimeout:-1 tag:0]方法
這里的-1為等待時間庭呜，如果寫為-1意思為無限等待滑进，tag指定會話標(biāo)示。
---注意
(**) [sock readDataToData:[GCDAsyncSocket CRLFData] withTimeout:-1 tag:0] 這一句募谎；
這一句的意思是接收到[GCDAsyncSocket CRLFData] 這個邊界扶关，觸發(fā)代理，至于[GCDAsyncSocket CRLFData]是什么下面會介紹数冬。
上文說過节槐，沒發(fā)送一次消息，就對應(yīng)寫一個read消息，這樣才能觸發(fā)- (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag方法來接收回調(diào)铜异。

3.重點(diǎn)來了：這一塊牽扯到數(shù)據(jù)包的處理地来。我們看下發(fā)送消息和發(fā)送心跳包的方法：

/*給B發(fā)消息**/
-(void)sendMSGToB{
    NSData *data  =  [@"Hello" dataUsingEncoding:NSUTF8StringEncoding];
    NSData *data1  = [@"I" dataUsingEncoding:NSUTF8StringEncoding];
    NSData *data2  = [@"am" dataUsingEncoding:NSUTF8StringEncoding];
    NSData *data3  = [@"A," dataUsingEncoding:NSUTF8StringEncoding];
    NSData *data4  = [@"nice to meet you!" dataUsingEncoding:NSUTF8StringEncoding];
    
    [self sendData:data :@"txt" toClinet:@"CinentB"];
    [self sendData:data1 :@"txt" toClinet:@"CinentB"];
    [self sendData:data2 :@"txt" toClinet:@"CinentB"];
    [self sendData:data3 :@"txt" toClinet:@"CinentB"];
    [self sendData:data4 :@"txt" toClinet:@"CinentB"];
    
    NSString *filePath = [[NSBundle mainBundle]pathForResource:@"7" ofType:@"jpeg"];
    
    NSData *data5 = [NSData dataWithContentsOfFile:filePath];
    
    [self sendData:data5 :@"img" toClinet:@"CinentB"];

}
/*封裝報文**/
- (void)sendData:(NSData *)data :(NSString *)type toClinet:(NSString *)target;
{
    NSUInteger size = data.length;
    
    NSMutableDictionary *headDic = [NSMutableDictionary dictionary];
    [headDic setObject:type forKey:@"type"];
    [headDic setObject:@"CinentA" forKey:@"CinentID"];
    [headDic setObject:target forKey:@"targetID"];
    [headDic setObject:[NSString stringWithFormat:@"%ld",size] forKey:@"size"];
    NSString *jsonStr = [self dictionaryToJson:headDic];
    NSData *lengthData = [jsonStr dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableData *mData = [NSMutableData dataWithData:lengthData];
    //分界
    [mData appendData:[GCDAsyncSocket CRLFData]];
    
    [mData appendData:data];
    
    
    //第二個參數(shù)，請求超時時間
    [self.clinetSocket writeData:mData withTimeout:-1 tag:0];
    
}
//字典轉(zhuǎn)為Json字符串
- (NSString *)dictionaryToJson:(NSDictionary *)dic
{
    NSError *error = nil;
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dic options:NSJSONWritingPrettyPrinted error:&error];
    return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}

這里就是做封包處理了：

在這里主要是發(fā)了幾條消息和一個圖片給ClientB熙掺。
我們定義了一個headDic未斑，這個是我們數(shù)據(jù)包的頭部，里面裝了這個數(shù)據(jù)包的大小和類型信息币绩，自身客戶端ID蜡秽，和目標(biāo)客戶端ID（當(dāng)然，你可以裝更多的其他標(biāo)識信息缆镣。）然后我們把它轉(zhuǎn)成了json芽突，最后轉(zhuǎn)成data。
然后我們把這個head拼在最前面董瞻，接著拼了一個：

[GCDAsyncSocket CRLFData]

這個是什么呢寞蚌？其實(shí)它就是一個\r\n。我們用它來做頭部的邊界钠糊。（又或者我們可以規(guī)定一個固定的頭部長度挟秤，來作為邊界）。
最后我們把真正的數(shù)據(jù)包給拼接上抄伍。

這一塊借鑒了涂耀輝的《即時通訊下數(shù)據(jù)粘包艘刚、斷包處理實(shí)例（基于CocoaAsyncSocket）》一文。也看過別的幾種處理方式截珍，但是感覺這種處理方式比較容易理解也好用一些攀甚。

4.最后我們還做了一個客戶端的斷開重連的例子（只是舉個例子，大家還是不要這樣干）岗喉。

//斷開連接調(diào)用
-(void)socketDidDisconnect:(GCDAsyncSocket *)sock withError:(NSError *)err{
    NSLog(@"%@",[NSString stringWithFormat:@"%@：斷開連接(Error:%@)",self.class,err]);
      self.clientAmsg([NSString stringWithFormat:@"%@：斷開連接(Error:%@)",self.class,err]);
    if (err) {
        //重連
        self.isAgain=YES;
       [self.clinetSocket connectToHost:HOST onPort:PORT error:nil];
    }else{
        self.clinetSocket.delegate=nil;
        self.clinetSocket=nil;
        //斷開
    }
    
}

客戶端基本就是這些東西了秋度，至于對應(yīng)的解包處理我想放到服務(wù)端來講，原理都是一樣的钱床。
???休息下荚斯，不知道有幾個同學(xué)能看到這里，如果你看到這里說明你是一個很有耐心的程序員了诞丽，不知道各位能看到這里的同學(xué)有沒有一些混亂鲸拥，個人語音能力有限，實(shí)在抱歉僧免。還是看代碼清晰刑赶，其實(shí)客戶端這一部分就做三件事：1.連接服務(wù)器，維持心跳懂衩。2.封包撞叨，通過服務(wù)器給指定客戶端發(fā)送消息金踪。3接收服務(wù)器消息。下面我們將開始服務(wù)端的部分??

3.服務(wù)端：

老規(guī)矩牵敷，貼代碼

.h

#import <Foundation/Foundation.h>


typedef void(^clientAMSG)(NSString *msg) ;

@interface ClientA : NSObject
@property(nonatomic,copy)clientAMSG clientAmsg;
+(id)sharClineA;
/*連接服務(wù)器**/
-(BOOL)connect;
/*給B發(fā)消息**/
-(void)sendMSGToB;
-(void)ClientAGetMSG:(clientAMSG)clientAmsg;
@end

.h文件沒什么好說的胡岔。

.m

代碼比較簡單，先貼出來枷餐，后面做解釋靶瘸，拿到項目的各位可以直接不看這一塊在xcode里打開。

#import "Sever.h"
#import "GCDAsyncSocket.h"

static dispatch_queue_t CGD_manager_SEVER_queue() {
    static dispatch_queue_t _CGD_manager_SEVER_queue;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _CGD_manager_SEVER_queue = dispatch_queue_create("gcd.mine.queue.SeverAkey", DISPATCH_QUEUE_CONCURRENT);
    });
    return _CGD_manager_SEVER_queue;
}
//儲存在本地的客戶端類型
@interface Client : NSObject
@property(nonatomic, strong)GCDAsyncSocket *scocket;//客戶端scocket
@property(nonatomic, strong)NSDate *timeOfSocket;  //更新通訊時間
@property(nonatomic,strong) NSDictionary *currentPacketHead;//客戶端報文字典
@property(nonatomic,copy)NSString * clientID;//客戶端ID
@end
@implementation Client
@end



@interface Sever () <GCDAsyncSocketDelegate>
@property(nonatomic, strong)GCDAsyncSocket *serve;
@property(nonatomic, strong)NSMutableArray *clientsArray;// 儲存客戶端
@property(nonatomic, strong)NSThread *checkThread;// 檢測心跳
@end

@implementation Sever
+(instancetype)sharSever{
    static Sever * sever;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sever=[[Sever alloc]init];
    });
    return sever;
}
-(instancetype)init{
    if (self = [super init]) {
        self.serve = [[GCDAsyncSocket alloc] initWithDelegate:self delegateQueue:CGD_manager_SEVER_queue()];
        self.checkThread = [[NSThread alloc]initWithTarget:self selector:@selector(checkClient) object:nil];
        [self.checkThread start];
    }
    
    return self;
}
-(NSMutableArray *)clientsArray{
    if (!_clientsArray) {
        _clientsArray = [NSMutableArray array];
    }
    
    return _clientsArray;
}
-(void)SeverGetMSG:(SeverMSG)severAmsg{
    self.severAmsg =severAmsg;
}
//監(jiān)控端口
-(void)openSerVice{
    
    NSError *error;
    BOOL sucess = [self.serve acceptOnPort:8088 error:&error];
    if (sucess) {
        NSLog(@"%@",[NSString stringWithFormat:@"%@---監(jiān)聽端口成功,等待客戶端請求連接...",self.class]);
        if (self.severAmsg) {
            self.severAmsg([NSString stringWithFormat:@"%@---監(jiān)聽端口成功,等待客戶端請求連接...",self.class]);
        }
        
    }else {
        NSLog(@"%@",[NSString stringWithFormat:@"%@---端口開啟失敗...",self.class]);
        if (self.severAmsg) {
            self.severAmsg([NSString stringWithFormat:@"%@---端口開啟失敗...",self.class]);
        }
    }
}

#pragma mark  GCDAsyncSocketDelegate
- (void)socket:(GCDAsyncSocket *)serveSock didAcceptNewSocket:(GCDAsyncSocket *)newSocket{
    if (self.severAmsg) {
        self.severAmsg([NSString stringWithFormat:@"%@---%@ IP: %@: %zd 客戶端請求連接...",self.class,newSocket,newSocket.connectedHost,newSocket.connectedPort]);
    }
    NSLog(@"%@---%@ IP: %@: %zd 客戶端請求連接...",self.class,newSocket,newSocket.connectedHost,newSocket.connectedPort);
    // 1.將客戶端socket保存起來
    Client *client = [[Client alloc]init];
    client.scocket = newSocket;
    client.timeOfSocket = [NSDate date];
    [self.clientsArray addObject:client];
    [newSocket readDataToData:[GCDAsyncSocket CRLFData] withTimeout:-1 tag:0];
    
}
- (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag  {
    Client * client=[self getClientBysocket:sock];
    if (!client) {
        [sock readDataToData:[GCDAsyncSocket CRLFData] withTimeout:-1 tag:0];
        return;
    }
    //先讀取到當(dāng)前數(shù)據(jù)包頭部信息
    if (!client.currentPacketHead) {
        client.currentPacketHead = [NSJSONSerialization
                                    JSONObjectWithData:data
                                    options:NSJSONReadingMutableContainers
                                    error:nil];
        if (!client.currentPacketHead) {
            NSLog(@"error：當(dāng)前數(shù)據(jù)包的頭為空");
            if (self.severAmsg) {
                self.severAmsg(@"error：當(dāng)前數(shù)據(jù)包的頭為空");
            }
            //斷開這個socket連接或者丟棄這個包的數(shù)據(jù)進(jìn)行下一個包的讀取
            //....
            return;
        }
        NSUInteger packetLength = [client.currentPacketHead[@"size"] integerValue];
        //讀到數(shù)據(jù)包的大小
        [sock readDataToLength:packetLength withTimeout:-1 tag:0];
        return;
    }
    //正式的包處理
    NSUInteger packetLength = [client.currentPacketHead[@"size"] integerValue];
    //說明數(shù)據(jù)有問題
    if (packetLength <= 0 || data.length != packetLength) {
        NSString *msg = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
        NSLog(@"error：當(dāng)前數(shù)據(jù)包數(shù)據(jù)大小不正確(%@)",msg);
        if (self.severAmsg) {
            self.severAmsg([NSString stringWithFormat:@"error：當(dāng)前數(shù)據(jù)包數(shù)據(jù)大小不正確(%@)",msg]);
        }
        return;
    }
    //分配ID
    NSString *clientID=client.currentPacketHead[@"CinentID"];
    client.clientID=clientID;
    NSString *targetID=client.currentPacketHead[@"targetID"];
    NSString *type = client.currentPacketHead[@"type"];
    
    
    
    
    /*
     *服務(wù)端可以不解析內(nèi)容毛肋，直接轉(zhuǎn)發(fā)出去怨咪，這里只是想看看打印消息
     **/
    if ([type isEqualToString:@"img"]) {
        NSLog(@"收到圖片");
        if (self.severAmsg) {
            self.severAmsg(@"收到圖片");
        }
    }else{
        NSString *msg = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
        if (self.severAmsg) {
            self.severAmsg([NSString stringWithFormat:@"收到消息:%@",msg]);
        }
        NSLog(@"收到消息:%@",msg);
    }
    
    
    
    
    for (Client *socket in self.clientsArray) {
        //這里找不到目標(biāo)客戶端，可以把數(shù)據(jù)保存起來润匙，等待目標(biāo)客戶端上線诗眨，再轉(zhuǎn)發(fā)出去，這里就不做了孕讳，感興趣的同學(xué)自己可以試一試
        if ([socket.clientID isEqualToString:targetID]) {
            [self writeDataWithSocket:socket.scocket data:data type:type sourceClient:clientID];
        }
    }
    client.currentPacketHead = nil;
    [sock readDataToData:[GCDAsyncSocket CRLFData] withTimeout:-1 tag:0];
}
-(Client *)getClientBysocket:(GCDAsyncSocket *)sock{
    for (Client *socket in self.clientsArray) {
        if ([sock isEqual:socket.scocket]) {
            ///更新最新時間
            socket.timeOfSocket = [NSDate date];
            return socket;
        }
    }
    return nil;
}
- (void)socketDidDisconnect:(GCDAsyncSocket *)sock withError:(NSError *)err{
    if (self.severAmsg) {
        self.severAmsg([NSString stringWithFormat:@"%@---有用戶下線...",self.class]);
    }
    NSLog(@"%@",[NSString stringWithFormat:@"%@---有用戶下線...",self.class]);
    NSMutableArray *arrayNew = [NSMutableArray array];
    for (Client *socket in self.clientsArray ) {
        if ([socket.scocket isEqual:sock]) {
            continue;
        }
        [arrayNew addObject:socket   ];
    }
    self.clientsArray = arrayNew;
}

-(void)exitWithSocket:(GCDAsyncSocket *)clientSocket{
    //    [self writeDataWithSocket:clientSocket str:@"成功退出\n"];
    //    [self.arrayClient removeObject:clientSocket];
    //
    //    NSLog(@"當(dāng)前在線用戶個數(shù):%ld",self.arrayClient.count);
}

- (void)socket:(GCDAsyncSocket *)sock didWriteDataWithTag:(long)tag{
    if (self.severAmsg) {
        self.severAmsg([NSString stringWithFormat:@"%@---數(shù)據(jù)發(fā)送成功.....",self.class]);
    }
    NSLog(@"%@",[NSString stringWithFormat:@"%@---數(shù)據(jù)發(fā)送成功.....",self.class]);
}

- (void)writeDataWithSocket:(GCDAsyncSocket*)clientSocket data:(NSData *)data type:(NSString *)type sourceClient:(NSString *)sourceClient {
    NSUInteger size = data.length;
    NSMutableDictionary *headDic = [NSMutableDictionary dictionary];
    [headDic setObject:type forKey:@"type"];
    [headDic setObject:sourceClient forKey:@"sourceClient"];
    [headDic setObject:[NSString stringWithFormat:@"%ld",size] forKey:@"size"];
    NSString *jsonStr = [self dictionaryToJson:headDic];
    NSData *lengthData = [jsonStr dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableData *mData = [NSMutableData dataWithData:lengthData];
    //分界
    [mData appendData:[GCDAsyncSocket CRLFData]];
    [mData appendData:data];
    //第二個參數(shù)匠楚，請求超時時間
    [clientSocket writeData:mData withTimeout:-1 tag:0];
    
}
//字典轉(zhuǎn)為Json字符串
- (NSString *)dictionaryToJson:(NSDictionary *)dic
{
    NSError *error = nil;
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dic options:NSJSONWritingPrettyPrinted error:&error];
    return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}

#pragma checkTimeThread

//開啟線程 啟動runloop 循環(huán)檢測客戶端socket最新time
- (void)checkClient{
    @autoreleasepool {
        [NSTimer scheduledTimerWithTimeInterval:30 target:self selector:@selector(repeatCheckClinet) userInfo:nil repeats:YES];
        [[NSRunLoop currentRunLoop]run];
    }
}

//移除 超過心跳的 client
- (void)repeatCheckClinet{
    if (self.clientsArray.count == 0) {
        return;
    }
    NSDate *date = [NSDate date];
    NSMutableArray *arrayNew = [NSMutableArray array];
    for (Client *socket in self.clientsArray ) {
        if ([date timeIntervalSinceDate:socket.timeOfSocket]>20||!socket) {
            if (socket) {
                [socket.scocket disconnect];
            }
            
            continue;
        }
        [arrayNew addObject:socket];
    }
    self.clientsArray = arrayNew;
}
@end

看過客戶端的流程，再來看服務(wù)端就簡單很多厂财。說下思路：

1.跟客戶端一樣芋簿，先做單例，構(gòu)造隊列初始化服務(wù)端Socket蟀苛，設(shè)置代理益咬。

+(instancetype)sharSever{
    static Sever * sever;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sever=[[Sever alloc]init];
    });
    return sever;
}
-(instancetype)init{
    if (self = [super init]) {
        self.serve = [[GCDAsyncSocket alloc] initWithDelegate:self delegateQueue:CGD_manager_SEVER_queue()];
        self.checkThread = [[NSThread alloc]initWithTarget:self selector:@selector(checkClient) object:nil];
        [self.checkThread start];
    }
    
    return self;
}
-(NSMutableArray *)clientsArray{
    if (!_clientsArray) {
        _clientsArray = [NSMutableArray array];
    }
    
    return _clientsArray;
}

2.監(jiān)聽本地端口

//監(jiān)控端口
-(void)openSerVice{
    
    NSError *error;
    BOOL sucess = [self.serve acceptOnPort:8088 error:&error];
    if (sucess) {
        NSLog(@"%@",[NSString stringWithFormat:@"%@---監(jiān)聽端口成功,等待客戶端請求連接...",self.class]);
        if (self.severAmsg) {
            self.severAmsg([NSString stringWithFormat:@"%@---監(jiān)聽端口成功,等待客戶端請求連接...",self.class]);
        }
        
    }else {
        NSLog(@"%@",[NSString stringWithFormat:@"%@---端口開啟失敗...",self.class]);
        if (self.severAmsg) {
            self.severAmsg([NSString stringWithFormat:@"%@---端口開啟失敗...",self.class]);
        }
    }
}

3.接收到新的socket連接到本地端口，會觸發(fā)代理調(diào)用

- (void)socket:(GCDAsyncSocket *)serveSock didAcceptNewSocket:(GCDAsyncSocket *)newSocket{
    if (self.severAmsg) {
        self.severAmsg([NSString stringWithFormat:@"%@---%@ IP: %@: %zd 客戶端請求連接...",self.class,newSocket,newSocket.connectedHost,newSocket.connectedPort]);
    }
    NSLog(@"%@---%@ IP: %@: %zd 客戶端請求連接...",self.class,newSocket,newSocket.connectedHost,newSocket.connectedPort);
    // 1.將客戶端socket保存起來
    Client *client = [[Client alloc]init];
    client.scocket = newSocket;
    client.timeOfSocket = [NSDate date];
    [self.clientsArray addObject:client];
    [newSocket readDataToData:[GCDAsyncSocket CRLFData] withTimeout:-1 tag:0];
    
}

這里還是蠻重要的帜平，解釋下：在接到新的socket連接后，我們創(chuàng)建一個Client 類型的對象梅鹦，將當(dāng)前socket交給這個對象裆甩，再將這個Client用一個可變數(shù)組self.clientsArray保存起來。（這個數(shù)組用來保存所有連接到服務(wù)器的socket對應(yīng)創(chuàng)建的Client對象齐唆，后面會利用它來處理心跳嗤栓，轉(zhuǎn)發(fā)，和用戶調(diào)度）箍邮。然后讓當(dāng)socket前讀取有[GCDAsyncSocket CRLFData]邊界的報文茉帅。

可以看下Client對象的聲明:

//儲存在本地的客戶端類型
@interface Client : NSObject
@property(nonatomic, strong)GCDAsyncSocket *scocket;//客戶端scocket
@property(nonatomic, strong)NSDate *timeOfSocket;  //更新通訊時間
@property(nonatomic,strong) NSDictionary *currentPacketHead;//客戶端報文字典
@property(nonatomic,copy)NSString * clientID;//客戶端ID
@end
@implementation Client
@end

繼承自NSObject類，里面包含4個屬性：

scocket屬性: 對應(yīng)每個客戶端連接過來的scocket锭弊；
timeOfSocket屬性: 對應(yīng)每個客戶端最后和服務(wù)器交互時間堪澎；
currentPacketHead屬性: 用來儲存用戶數(shù)據(jù)包報頭；
clientID屬性: 對應(yīng)每個客戶端分配到的ID味滞；

4.接收數(shù)據(jù)

- (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag  {
    Client * client=[self getClientBysocket:sock];
    if (!client) {
        [sock readDataToData:[GCDAsyncSocket CRLFData] withTimeout:-1 tag:0];
        return;
    }
    //先讀取到當(dāng)前數(shù)據(jù)包頭部信息
    if (!client.currentPacketHead) {
        client.currentPacketHead = [NSJSONSerialization
                                    JSONObjectWithData:data
                                    options:NSJSONReadingMutableContainers
                                    error:nil];
        if (!client.currentPacketHead) {
            NSLog(@"error：當(dāng)前數(shù)據(jù)包的頭為空");
            if (self.severAmsg) {
                self.severAmsg(@"error：當(dāng)前數(shù)據(jù)包的頭為空");
            }
            //斷開這個socket連接或者丟棄這個包的數(shù)據(jù)進(jìn)行下一個包的讀取
            //....
            return;
        }
        NSUInteger packetLength = [client.currentPacketHead[@"size"] integerValue];
        //讀到數(shù)據(jù)包的大小
        [sock readDataToLength:packetLength withTimeout:-1 tag:0];
        return;
    }
    //正式的包處理
    NSUInteger packetLength = [client.currentPacketHead[@"size"] integerValue];
    //說明數(shù)據(jù)有問題
    if (packetLength <= 0 || data.length != packetLength) {
        NSString *msg = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
        NSLog(@"error：當(dāng)前數(shù)據(jù)包數(shù)據(jù)大小不正確(%@)",msg);
        if (self.severAmsg) {
            self.severAmsg([NSString stringWithFormat:@"error：當(dāng)前數(shù)據(jù)包數(shù)據(jù)大小不正確(%@)",msg]);
        }
        return;
    }
    //分配ID
    NSString *clientID=client.currentPacketHead[@"CinentID"];
    client.clientID=clientID;
    NSString *targetID=client.currentPacketHead[@"targetID"];
    NSString *type = client.currentPacketHead[@"type"];
    
    
    
    
    /*
     *服務(wù)端可以不解析內(nèi)容樱蛤，直接轉(zhuǎn)發(fā)出去钮呀，這里只是想看看打印消息
     **/
    if ([type isEqualToString:@"img"]) {
        NSLog(@"收到圖片");
        if (self.severAmsg) {
            self.severAmsg(@"收到圖片");
        }
    }else{
        NSString *msg = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
        if (self.severAmsg) {
            self.severAmsg([NSString stringWithFormat:@"收到消息:%@",msg]);
        }
        NSLog(@"收到消息:%@",msg);
    }
    
    
    
    
    for (Client *socket in self.clientsArray) {
        //這里找不到目標(biāo)客戶端，可以把數(shù)據(jù)保存起來昨凡，等待目標(biāo)客戶端上線爽醋，再轉(zhuǎn)發(fā)出去，這里就不做了便脊，感興趣的同學(xué)自己可以試一試
        if ([socket.clientID isEqualToString:targetID]) {
            [self writeDataWithSocket:socket.scocket data:data type:type sourceClient:clientID];
        }
    }
    client.currentPacketHead = nil;
    [sock readDataToData:[GCDAsyncSocket CRLFData] withTimeout:-1 tag:0];
}

這一塊算是服務(wù)端核心的部分了蚂四，數(shù)據(jù)包的拆解，分發(fā)哪痰，用戶調(diào)度遂赠，心跳刷新都在這里處理。
大體思路：監(jiān)聽到有[GCDAsyncSocket CRLFData] 邊界的數(shù)據(jù)包妒御，調(diào)用didReadData方法解愤，在這個方法里。先根據(jù)當(dāng)前sock找到self.clientsArray（存儲所有client和相關(guān)信息）里找到對應(yīng)的Client乎莉，在找的過程中送讲，將找到的對應(yīng)的Client的timeOfSocket（可以理解為時間戳）刷新。
判斷對應(yīng)Client的currentPacketHead是否為nil惋啃。如果為空哼鬓，將收到的data轉(zhuǎn)化為字典賦值給currentPacketHead。此時currentPacketHead的內(nèi)容應(yīng)該為

{
@"size":@"****",//攜帶內(nèi)容的大小
@"CinentID":@"****",//源客戶端id
@"type":@"****",//攜帶數(shù)據(jù)格式
@"targetID":@"****"http://目的客戶端id
....當(dāng)然我們還可以封裝一些別的信息边灭，我們這里就設(shè)計這幾個我們需要的
}

然后异希，通知當(dāng)前socket來接收size對應(yīng)長度的數(shù)據(jù)包。
理想狀態(tài)下（這里會有并發(fā)過程绒瘦，這里先提一下称簿，后面解釋）該sockt會去讀到size長度的內(nèi)容包，檢測下內(nèi)容包的合理性惰帽，如果合理憨降。我們就取到正確的內(nèi)容了，然后该酗，根據(jù)根據(jù)收到的內(nèi)容給此Client分配clientID授药，根據(jù)報文目的客戶端id，在self.clientsArray中找到對應(yīng)Client所對應(yīng)的socket呜魄，再將內(nèi)容封裝轉(zhuǎn)發(fā)悔叽。客戶端的解析過程爵嗅，和這里大體相似娇澎，不表。

上面說到用戶并發(fā)操骡，因?yàn)樗械目蛻舳硕紩瑫r發(fā)送心跳包或用戶消息九火，都會調(diào)用didReadData方法赚窃，比如說用戶A對應(yīng)的socket讀取到報文頭部，要去讀報文內(nèi)容的時候岔激，用戶B對應(yīng)的socket也同時調(diào)用didReadData方法勒极，那么會照成我們接收到數(shù)據(jù)處理混亂。所以虑鼎，我們封裝一個Client來對應(yīng)處理每個客戶端的socket事務(wù)辱匿，通過定位標(biāo)記，讓他們并發(fā)工作炫彩，各自維持自己處理數(shù)據(jù)的邏輯匾七，互不干擾。

5.心跳檢測

//開啟線程 啟動runloop 循環(huán)檢測客戶端socket最新time
- (void)checkClient{
    @autoreleasepool {
        [NSTimer scheduledTimerWithTimeInterval:30 target:self selector:@selector(repeatCheckClinet) userInfo:nil repeats:YES];
        [[NSRunLoop currentRunLoop]run];
    }
}

//移除 超過心跳的 client
- (void)repeatCheckClinet{
    if (self.clientsArray.count == 0) {
        return;
    }
    NSDate *date = [NSDate date];
    NSMutableArray *arrayNew = [NSMutableArray array];
    for (Client *socket in self.clientsArray ) {
        if ([date timeIntervalSinceDate:socket.timeOfSocket]>20||!socket) {
            if (socket) {
                [socket.scocket disconnect];
            }
            
            continue;
        }
        [arrayNew addObject:socket];
    }
    self.clientsArray = arrayNew;
}

這一塊很簡單江兢，做法是昨忆，沒收到客戶端發(fā)過來的報文，就更新下杉允，客戶端最后交互時間（timeOfSocket）邑贴，然后，每隔一段時間檢測self.clientsArray每個Client對應(yīng)的timeOfSocket叔磷，和目前時間對比拢驾，如果超出預(yù)先設(shè)定的失活時間，就斷開此Client對應(yīng)的scocket改基，殺死客戶端繁疤。

寫在最后

???到這里，就全部講完了秕狰，文章篇幅比較長稠腊，但大多是代碼部分，對CocoaAsyncSocket有了解的同學(xué)鸣哀，可以直接看代碼麻养，比較簡單，可能很多同學(xué)看到這種又臭又長的文章诺舔，會選擇直接略過。嘴拙备畦，總想用更多的文字來解釋低飒，還是怕自己表達(dá)的不夠清晰，水平有限懂盐，文章和代碼中多有漏洞褥赊，歡迎指出，內(nèi)心忐忑莉恼，只愿不要誤人子弟就好拌喉。同時也希望能拋磚引玉速那，給有需要的同學(xué)一些思路和啟發(fā)。??