socket编程

• 前言
• AsyncSocket介绍
• AsyncSocket详解
• AsyncSocket示例

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一、前言

公司的项目用到了Socket编程，之前在学习的过程当中，用到的更多的还是http请求的方式。但是既然用到了就必须学习一下，所以就在网上找一些例子，然后想自己写一个demo。可是发现很多写iOS Socket的博客并没有很详细的说明，也可能是大神们觉得其他东西都浅显易懂。

自己专研了一下，将自己的一些理解总结出来，一方面整理自己的学习思路，另一方面，为一些和我有同样困惑的小伙伴们，稍做指引。

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二、 AsyncSocket介绍

iOS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。

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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。

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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