1⃣️iOS中Socket编程的方式有哪些？
－BSD Socket
BSD Socket 是UNIX系统中通用的网络接口，它不仅支持各种不同的网络类型，而且也是一种内部进程之间的通信机制。而iOS系统其实本质就是UNIX，所以可以用，但是比较复杂。
－CFSocket
CFSocket是苹果提供给我们的使用Socket的方式，但是用起来还是会不太顺手。当然想使用的话，可以细细研究一下。
－AsyncSocket
这次博客的主讲内容，也是我们在开发项目中经常会用到的。
2⃣️为什么选择AsyncSocket？
iphone的CFNetwork编程比较艰深。使用AsyncSocket开源库来开发相对较简单，帮助我们封装了很多东西。
三、AsyncSocket详解
1⃣️说明
在我们开发当中，我们主要的任务是开发客户端。所以详解里主要将客户端的整个连接建立过程，以及在说明时候回调哪些函数。在后面的示例代码中，也会给出服务器端的简单开发。
2⃣️过程详解
1.建立连接
- (int)connectServer:(NSString *)hostIP port:(int)hostPort
2.连接成功后，会回调的函数
- (void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port
3.发送数据
- (void)writeData:(NSData *)data withTimeout:(NSTimeInterval)timeout tag:(long)tag;
4.接受数据
-(void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag
5.断开连接
- (void)onSocket:(AsyncSocket *)sock willDisconnectWithError:(NSError *)err
- (void)onSocketDidDisconnect:(AsyncSocket *)sock
主要就是上述的几个方法，只是说在真正开发当中，很可能我们在收发数据的时候，我们收发的数据并不仅仅是一个字符串包装成NSData即可，我们很可能会发送结构体等类型，这个时候我们就需要和服务器端的人员协作来开发：定义怎样的结构体。
四、AsyncSocket示例
客户端代码
#import "ViewController.h"#define SRV_CONNECTED 0#define SRV_CONNECT_SUC 1#define SRV_CONNECT_FAIL 2#define HOST_IP @"192.168.83.40"#define HOST_PORT 8008@interface ViewController (){ NSString *_content;}-(int) connectServer: (NSString *) hostIP port:(int) hostPort;-(void)showMessage:(NSString *) msg;@end@implementation ViewController@synthesize clientSocket,tbInputMsg,lblOutputMsg;#pragma mark - view lifecycle- (void)viewDidLoad{ [super viewDidLoad]; [self connectServer:HOST_IP port:HOST_PORT];}- (void)viewDidUnload{ [super viewDidUnload]; [clientSocket release], clientSocket = nil; [tbInputMsg release], tbInputMsg = nil; [lblOutputMsg release], lblOutputMsg = nil;}- (int)connectServer:(NSString *)hostIP port:(int)hostPort{ if (clientSocket == nil) { // 在需要联接地方使用connectToHost联接服务器 clientSocket = [[AsyncSocket alloc] initWithDelegate:self]; NSError *err = nil; if (![clientSocket connectToHost:hostIP onPort:hostPort error:&err]) { NSLog(@"Error %d:%@", err.code, [err localizedDescription]); UIAlertView *alert = [[UIAlertView alloc] initWithTitle:[@"Connection failed to host" stringByAppendingString:hostIP] message:[NSString stringWithFormat:@"%d:%@",err.code,err.localizedDescription] delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil]; [alert show]; [alert release]; return SRV_CONNECT_FAIL; } else { NSLog(@"Connected!"); return SRV_CONNECT_SUC; } } else { return SRV_CONNECTED; }}#pragma mark - IBAction// 发送数据- (IBAction) sendMsg:(id)sender{ NSString *inputMsgStr = tbInputMsg.text; NSString * content = [inputMsgStr stringByAppendingString:@"\r\n"]; NSLog(@"%@",content); NSData *data = [content dataUsingEncoding:NSUTF8StringEncoding]; // NSData *data = [content dataUsingEncoding:NSISOLatin1StringEncoding]; [clientSocket writeData:data withTimeout:-1 tag:0];}// 连接/重新连接- (IBAction) reconnect:(id)sender{ int stat = [self connectServer:HOST_IP port:HOST_PORT]; switch (stat) { case SRV_CONNECT_SUC: [self showMessage:@"connect success"]; break; case SRV_CONNECTED: [self showMessage:@"It's connected,don't agian"]; break; default: break; }}- (void)showMessage:(NSString *)msg{ UIAlertView * alert = [[UIAlertView alloc]initWithTitle:@"Alert!" message:msg delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; [alert show]; [alert release];}- (IBAction)textFieldDoneEditing:(id)sender{ [tbInputMsg resignFirstResponder];}- (IBAction)backgroundTouch:(id)sender{ [tbInputMsg resignFirstResponder];}#pragma mark socket delegate- (void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port{ [clientSocket readDataWithTimeout:-1 tag:0];}- (void)onSocket:(AsyncSocket *)sock willDisconnectWithError:(NSError *)err{ NSLog(@"Error");}- (void)onSocketDidDisconnect:(AsyncSocket *)sock{ NSString *msg = @"Sorry this connect is failure"; [self showMessage:msg]; [msg release]; clientSocket = nil;}- (void)onSocketDidSecure:(AsyncSocket *)sock{}// 接收到数据（可以通过tag区分）-(void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag{ NSString* aStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]; _content = lblOutputMsg.text; NSLog(@"Hava received datas is :%@",aStr); NSString *newStr = [NSString stringWithFormat:@"\n%@", aStr]; lblOutputMsg.text = [_content stringByAppendingString:newStr]; [aStr release]; [clientSocket readDataWithTimeout:-1 tag:0];}@end 服务器端代码
#import "SocketView.h"#import "AsyncSocket.h"#define WELCOME_MSG 0#define ECHO_MSG 1#define FORMAT(format, ...) [NSString stringWithFormat:(format), ##__VA_ARGS__]@interface SocketView (PrivateAPI)- (void)logError:(NSString *)msg;- (void)logInfo:(NSString *)msg;- (void)logMessage:(NSString *)msg;@end@implementation SocketView// 初始化- (void)awakeFromNib{ listenSocket = [[AsyncSocket alloc] initWithDelegate:self]; [listenSocket setRunLoopModes:[NSArray arrayWithObject:NSRunLoopCommonModes]]; connectedSockets = [[NSMutableArray alloc] initWithCapacity:1]; isRunning = NO; [logView setString:@""]; // [portField setString:@"8080"];}- (IBAction)startStop:(id)sender{ if(!isRunning) { int port = [portField intValue]; if(port < 0 || port > 65535) { port = 0; // 会随即取端口 } NSError *error = nil; if(![listenSocket acceptOnPort:port error:&error]) { [self logError:FORMAT(@"Error starting server: %@", error)]; return; } [self logInfo:FORMAT(@"Echo server started on port %hu", [listenSocket localPort])]; isRunning = YES; [portField setEnabled:NO]; [startStopButton setTitle:@"Stop"]; } else { // Stop accepting connections [listenSocket disconnect]; // Stop any client connections int i; for(i = 0; i < [connectedSockets count]; i++) { // Call disconnect on the socket, // which will invoke the onSocketDidDisconnect: method, // which will remove the socket from the list. [[connectedSockets objectAtIndex:i] disconnect]; } [self logInfo:@"Stopped Echo server"]; isRunning = false; [portField setEnabled:YES]; [startStopButton setTitle:@"Start"]; }}- (void)scrollToBottom{ NSScrollView *scrollView = [logView enclosingScrollView]; NSPoint newScrollOrigin; if ([[scrollView documentView] isFlipped]) newScrollOrigin = NSMakePoint(0.0, NSMaxY([[scrollView documentView] frame])); else newScrollOrigin = NSMakePoint(0.0, 0.0); [[scrollView documentView] scrollPoint:newScrollOrigin];}- (void)logError:(NSString *)msg{ NSString *paragraph = [NSString stringWithFormat:@"%@\n", msg]; NSMutableDictionary *attributes = [NSMutableDictionary dictionaryWithCapacity:1]; [attributes setObject:[NSColor redColor] forKey:NSForegroundColorAttributeName]; NSAttributedString *as = [[NSAttributedString alloc] initWithString:paragraph attributes:attributes]; [as autorelease]; [[logView textStorage] appendAttributedString:as]; [self scrollToBottom];}- (void)logInfo:(NSString *)msg{ NSString *paragraph = [NSString stringWithFormat:@"%@\n", msg]; NSMutableDictionary *attributes = [NSMutableDictionary dictionaryWithCapacity:1]; [attributes setObject:[NSColor purpleColor] forKey:NSForegroundColorAttributeName]; NSAttributedString *as = [[NSAttributedString alloc] initWithString:paragraph attributes:attributes]; [as autorelease]; [[logView textStorage] appendAttributedString:as]; [self scrollToBottom];}- (void)logMessage:(NSString *)msg{ NSString *paragraph = [NSString stringWithFormat:@"%@\n", msg]; NSMutableDictionary *attributes = [NSMutableDictionary dictionaryWithCapacity:1]; [attributes setObject:[NSColor blackColor] forKey:NSForegroundColorAttributeName]; NSAttributedString *as = [[NSAttributedString alloc] initWithString:paragraph attributes:attributes]; [as autorelease]; [[logView textStorage] appendAttributedString:as]; [self scrollToBottom];}- (void)onSocket:(AsyncSocket *)sock didAcceptNewSocket:(AsyncSocket *)newSocket{ [connectedSockets addObject:newSocket];}// 客户连接成功！- (void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port{ [self logInfo:FORMAT(@"Accepted client %@:%hu", host, port)]; NSString *welcomeMsg = @"恭喜您,已经通过scoket连接上服务器!"; NSData *welcomeData = [welcomeMsg dataUsingEncoding:NSUTF8StringEncoding]; [sock writeData:welcomeData withTimeout:-1 tag:WELCOME_MSG]; // We could call readDataToData:withTimeout:tag: here - that would be perfectly fine. // If we did this, we'd want to add a check in onSocket:didWriteDataWithTag: and only // queue another read if tag != WELCOME_MSG.}- (void)onSocket:(AsyncSocket *)sock didWriteDataWithTag:(long)tag{ [sock readDataToData:[AsyncSocket CRLFData] withTimeout:-1 tag:0];}// 接收到数据- (void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag{ NSData *strData = [data subdataWithRange:NSMakeRange(0, [data length] - 2)]; NSString *recvMsg = [[[NSString alloc] initWithData:strData encoding:NSUTF8StringEncoding] autorelease]; if(recvMsg) { [self logMessage:recvMsg]; } else { [self logError:@"Error converting received data into UTF-8 String"]; } NSString *backStr = nil; for (AsyncSocket *socket in connectedSockets) { if ([sock isEqualTo:socket]) { backStr = [NSString stringWithFormat:@"我说: %@",recvMsg]; } else { backStr = [NSString stringWithFormat:@"他说: %@",recvMsg]; } } // 回发数据 NSData* backData = [backStr dataUsingEncoding:NSUTF8StringEncoding]; [sock writeData:backData withTimeout:-1 tag:ECHO_MSG];}- (void)onSocket:(AsyncSocket *)sock willDisconnectWithError:(NSError *)err{ [self logInfo:FORMAT(@"Client Disconnected: %@:%hu", [sock connectedHost], [sock connectedPort])];}- (void)onSocketDidDisconnect:(AsyncSocket *)sock{ [connectedSockets removeObject:sock];}@end 界面搭建
