iOS Socket深入剖析

来源：互联网发布：印度人口知乎编辑：程序博客网时间：2024/05/21 22:37

1.定义：

Socket是网络服务提供的一种套接字，通信两端都是Socket,网络通信通过Socket进行IO直接的传输，是一种长连接，让应用程序可以进行异步模式，提高速率，需要数据的时候才进行数据接收。

2.既然要了解Socket,就要对传输协议有一定的了解，可以把socket理解为封装TCP/IP协议API，TCP协议属于可靠性传输协议，需要进行三次握手（客户端发送信息到服务器，服务器响应发送到客户端，客户端响应后发送到服务器） UDP协议属于不可靠协议，是因为他不需要进行响应，就像知道一个大概的位置，然后就传送过去，每次能传64K左右的东西，传输速度很快，但是有时会丢包的情况。所以视频，或则QQ群聊会用到UDP协议，QQ在单人聊天的时候，应该是进行TCP协议，所以个人认为QQ采用的是混合模型。

3.网络通信的三大要素：IP地址，传输协议，端口号。

IP地址：设备的唯一标示符。

传输协议：TCP UDP等

端口号：1-1023都是系统自带，如果个人要用的话需要1024以后的。需要熟记几个端口号，80，25，21等这里就不一一叙述。

4.开始进行代码

iOS主要按照NSStream(流)来发送和接收数据，可以设置流的代理，对流的状态变化做出相应连接建立，设置网络连接，绑定到主机和端口号，设置输入输出代理，监听数据流的状态，将输入输出添加至运行循环，打开输入输出流。

发送消息给服务器，有可读取字节时，读取服务器返回的内容，到达流末尾时，关闭流，同时并从主运行循环中删除。

- (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode{

switch (eventCode) {

case NSStreamEventOpenCompleted:

NSLog(@"完成");

break;

case NSStreamEventHasBytesAvailable:

NSLog(@"字节可读");

[self readData];

break;

case NSStreamEventHasSpaceAvailable:

NSLog(@"可发送字节");

break;

case NSStreamEventErrorOccurred:

NSLog(@"连接错误");

break;

case NSStreamEventEndEncountered:

NSLog(@"断开连接");

[self closeConnect];

break;

default:

NSLog(@"异常错误");

break;

}

- (void)closeConnect{

//1.输入输出流

[_inputStream close];

[_outputStream close];

//跳出运行循环

[_inputStream removeFromRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

[_outputStream removeFromRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

}

-(void)readData{

//1.简历一个字节数组用于存放读取数据，大小为1024

uint8_t buf[1024];

//返回一个真实的数据大小

NSInteger len = [_inputStream read:buf maxLength:sizeof(buf)];

if (len > 0) {

NSData *data = [NSData dataWithBytes:buf length:len];

NSString *dataString = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];

[_dataArray addObject:dataString];

[self.tableView reloadData];

}

- (IBAction)login:(id)sender {

//iam:定义的用户名协议

NSString *userName = @"iam:Snowwing";

NSData *data = [userName dataUsingEncoding:NSUTF8StringEncoding];

[_outputStream write:data.bytes maxLength:data.length];

}

- (IBAction)connect:(id)sender {

//主机IP地址

NSString *host = @"127.0.0.1";

//端口号

int port = 12345;

//读写数据流要转换成OC

CFReadStreamRef readStream;

CFWriteStreamRef writeStream;

//绑定到主机和端口

CFStreamCreatePairWithSocketToHost(NULL, (__bridge CFStringRef)host, port, &readStream, &writeStream);

//将C语言输入输出流转换成OC

_inputStream = (__bridge NSInputStream *)(readStream);

_outputStream = (__bridge NSOutputStream *)(writeStream);

//设置代理

_inputStream.delegate = self;

_outputStream.delegate = self;

//将输入输出流添加至循环

[_inputStream scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

[_outputStream scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

//打开输入输出流

[_outputStream open];

[_inputStream open];

}

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{

NSString *tftext = textField.text;

NSString *msg = [NSString stringWithFormat:@"msg:%@",tftext];

NSData *data = [msg dataUsingEncoding:NSUTF8StringEncoding];

[_outputStream write:data.bytes maxLength:data.length];

textField.text = nil;

return YES;

}

这里的服务器是调用第三方的服务器接口进行描述的

- (void)socket:(GCDAsyncSocket *)sock didAcceptNewSocket:(GCDAsyncSocket *)newSocket {

if(![_clientSockets containsObject:newSocket]){

[_clientSockets addObject:newSocket];

NSLog(@"%@链接主机成功",newSocket);

[newSocket readDataWithTimeout:-1 tag:0];

}

- (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag {

//获得接受字符

NSString *recverStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

//对字符串尾部回车做处理

while ([recverStr hasSuffix:@"\n"] || [recverStr hasSuffix:@"\r"]) {

recverStr = [recverStr substringToIndex:recverStr.length - 2];

}

NSUInteger index = [_clientSockets indexOfObject:sock];

NSString *key = [NSString stringWithFormat:@"%lu",index];

if ([recverStr hasPrefix:@"iam:"] && _clientNames[key] == nil) {

recverStr = [recverStr componentsSeparatedByString:@":"][1];

//将名字设为key以便找到对应socket进行单聊

[_clientNames setObject:key forKey:recverStr];

//存入名字方便以后消息发送时查找名字

_clientNames[key] = [recverStr stringByAppendingString:@":"];

recverStr = [recverStr stringByAppendingString:@" has join!"];

for (GCDAsyncSocket *client in self.clientSockets) {

[client writeData:[recverStr dataUsingEncoding:NSUTF8StringEncoding] withTimeout:-1 tag:0];

}

}else if([recverStr hasPrefix:@"msg:"]){

NSString *name = _clientNames[key];

recverStr = [recverStr componentsSeparatedByString:@":"][1];

if ([recverStr hasPrefix:@"/to "]) {

NSString *toName = [recverStr componentsSeparatedByString:@" "][1];

recverStr = [recverStr componentsSeparatedByString:@" "][2];

recverStr = [name stringByAppendingString:recverStr];

if (_clientNames[toName]) {

GCDAsyncSocket *socket = [_clientSockets objectAtIndex:[_clientNames[toName] integerValue]];

[socket writeData:[recverStr dataUsingEncoding:NSUTF8StringEncoding] withTimeout:-1 tag:0];

}

}else {

recverStr = [name stringByAppendingString:recverStr];

for (GCDAsyncSocket *client in self.clientSockets) {

[client writeData:[recverStr dataUsingEncoding:NSUTF8StringEncoding] withTimeout:-1 tag:0];

}

}else if ([recverStr isEqualToString:@"quit"]) {

//断开连接

[sock setDelegate:nil];

[sock disconnect];

[_clientNames removeObjectForKey:key];

[_clientSockets removeObject:sock];

}

[sock readDataWithTimeout:-1 tag:0];

}

效果图：

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