转载文章，原地址：http://yimouleng.com/2015/02/04/Socket-AsyncSocket/
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。
二、AsyncSocket介绍
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:@” “];
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:@” %@“, 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:@”%@ “, 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:@”%@ “, 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:@”%@ “, 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
