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詳解iPhone 下AsyncSocket網絡庫編程是本文要介紹的內容，iphone的標准推薦CFNetwork C庫編程.但是編程比較煩躁。在其它OS往往用類來封裝的對Socket函數的處理。比如MFC的CAsysncSocket.在iphone也有類似於開源項目.cocoa AsyncSocket庫

官方網站:http://code.google.com/p/cocoaasyncsocket/

這裡只上例子，自己在項目中使用的，絕對能使用，如果有疑問，歡迎留言討論。

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注意，CAsysncSocket已經將tcp、udp的連接異步化處理，所以你只管在主線程調用即可

將AsyncSocket.h AsyncSocket.m 導入到你的工程中，

在自己建立的util中，加入一下代碼

[cpp] 
01.#pragma mark tcp  
02.- (void) connectToHost:(NSString*)host port:(int)port { 
03.    socket = [[AsyncSocket alloc] initWithDelegate:self]; //設置回調的delegate  
04.    //TODO 這裡需要在退出局域網模式下斷開  
05.    [socket disconnect];    //斷開tcp連接  
06.//    socket  
07.    NSLog(@"tcp connecting to host:%@,port:%d",host,port); 
08.    @try { 
09.        [socket connectToHost:host onPort:port error:nil]; 
10.        [socket readDataWithTimeout:-1 tag:1]; //這只超時，如果timeout為負數，則永遠不超時  
11.    } 
12.    @catch (NSException *exception) { //異常處理  
13.        NSLog(@"connect exception %@,%@", [exception name], [exception description]); 
14.    } 
15.} 
16.//相應的回調函數  
17.- (void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port{ 
18.    NSLog(@"did connect to host %@:%d", host, port); 
19.} 
20.- (void)sendMessage:(NSString*)msg { 
21.    NSLog(@"tcp send msg:%@",  msg); 
22.    [socket readDataWithTimeout:SOCKET_TIMEOUT tag:1]; 
23.    [socket writeData:[msg dataUsingEncoding:NSUTF8StringEncoding] withTimeout:SOCKET_TIMEOUT tag:1]; 
24.} 
25.- (void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag{ 
26.    NSString* message = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]autorelease]; 
27.    NSLog(@"%f receive ReadData is: %@",[[NSDate date] timeIntervalSince1970],message); 
28.    
29.} 
30.-(NSTimeInterval)onSocket:(AsyncSocket *)sock shouldTimeoutReadWithTag:(long)tag elapsed:(NSTimeInterval)elapsed bytesDone:(NSUInteger)length{ 
31.    NSLog(@"onSocket:shouldTimeout-ReadWithTag:-----------"); 
32.    return 0; 
33.} 
34.-(NSTimeInterval)onSocket:(AsyncSocket *)sock shouldTimeoutWriteWithTag:(long)tag elapsed:(NSTimeInterval)elapsed bytesDone:(NSUInteger)length{ 
35.    NSLog(@"onSocket:shouldTimeout-WriteWithTag:-----------"); 
36.    return 0; 
37.} 
38. 
39.-(void)onSocket:(AsyncSocket *)sock didWriteDataWithTag:(long)tag{ 
40.    NSLog(@"didWriteDataWithTag tag:%ld",tag); 
41.} 
42.-(void)onSocketDidDisconnect:(AsyncSocket *)sock{ 
43.    NSLog(@"onSocketDidDisconnect sock:%@",sock); 
44.    [viewController onLocalDisconnect:0]; 
45.     
46.} 
#pragma mark tcp
- (void) connectToHost:(NSString*)host port:(int)port {
    socket = [[AsyncSocket alloc] initWithDelegate:self]; //設置回調的delegate
    //TODO 這裡需要在退出局域網模式下斷開
    [socket disconnect];    //斷開tcp連接
//    socket
    NSLog(@"tcp connecting to host:%@,port:%d",host,port);
    @try {
        [socket connectToHost:host onPort:port error:nil];
        [socket readDataWithTimeout:-1 tag:1]; //這只超時，如果timeout為負數，則永遠不超時
    }
    @catch (NSException *exception) { //異常處理
        NSLog(@"connect exception %@,%@", [exception name], [exception description]);
    }
}
//相應的回調函數
- (void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port{
    NSLog(@"did connect to host %@:%d", host, port);
}
- (void)sendMessage:(NSString*)msg {
    NSLog(@"tcp send msg:%@",  msg);
    [socket readDataWithTimeout:SOCKET_TIMEOUT tag:1];
    [socket writeData:[msg dataUsingEncoding:NSUTF8StringEncoding] withTimeout:SOCKET_TIMEOUT tag:1];
}
- (void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag{
    NSString* message = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]autorelease];
    NSLog(@"%f receive ReadData is: %@",[[NSDate date] timeIntervalSince1970],message);
  
}
-(NSTimeInterval)onSocket:(AsyncSocket *)sock shouldTimeoutReadWithTag:(long)tag elapsed:(NSTimeInterval)elapsed bytesDone:(NSUInteger)length{
    NSLog(@"onSocket:shouldTimeout-ReadWithTag:-----------");
    return 0;
}
-(NSTimeInterval)onSocket:(AsyncSocket *)sock shouldTimeoutWriteWithTag:(long)tag elapsed:(NSTimeInterval)elapsed bytesDone:(NSUInteger)length{
    NSLog(@"onSocket:shouldTimeout-WriteWithTag:-----------");
    return 0;
}

-(void)onSocket:(AsyncSocket *)sock didWriteDataWithTag:(long)tag{
    NSLog(@"didWriteDataWithTag tag:%ld",tag);
}
-(void)onSocketDidDisconnect:(AsyncSocket *)sock{
    NSLog(@"onSocketDidDisconnect sock:%@",sock);
    [viewController onLocalDisconnect:0];
   
}