NSFileHandle函数acceptConnectionInBackgroundAndNotify在第二次调用时不工作

Question

我正在使用可可，我试图为我正在编写的程序创建一个tcp套接字服务器，我使用NSFileHandle和方法acceptConnectionInBackgroundAndNotify。我一直在关注here的代码。

我遇到的问题是我可以连接我的客户端一次，但是当我尝试再次连接时，我得到一个连接拒绝错误。

之前，我连首次命令sudo lsof的-i -P返回以下信息：

RubyBeat 23964 pauljohnson 8u IPv4 0x0632c274  0t0 TCP *:1234 (LISTEN) 

在第一时间与客户端连接后，我得到这个：

RubyBeat 23964 pauljohnson 5u IPv4 0x06a30334  0t0 TCP localhost:1234->localhost:51579 (CLOSED) 

我的应用程序似乎没有重新打开套接字，以便在第一次连接之后侦听连接，并在第二次尝试连接时获取错误编号22。

我在可可中使用垃圾收集，并想知道是否会导致套接字问题？

我的代码是：

[self createSocket]; 
} 

-(void)createSocket 
{ 
    // create socket and wait for events to come in 
    NSSocketPort* serverSock = [[NSSocketPort alloc] initWithTCPPort: 1234]; 
    socketHandle = [[NSFileHandle alloc] initWithFileDescriptor: [serverSock socket] 
               closeOnDealloc: NO]; 

    [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(newConnection:) 
               name: NSFileHandleConnectionAcceptedNotification 
               object: socketHandle]; 

    [socketHandle acceptConnectionInBackgroundAndNotify]; 
} 

- (void)newConnection:(NSNotification*)notification 
{ 
    NSLog(@"connection accepted"); 

    NSDictionary* userInfo = [notification userInfo]; 
    NSFileHandle* remoteFileHandle = [userInfo objectForKey: 
             NSFileHandleNotificationFileHandleItem]; 

    if([[userInfo allKeys] containsObject:@"NSFileHandleError"]){ 
     NSNumber* errorNo = [userInfo objectForKey:@"NSFileHandleError"]; 
     if(errorNo) { 
      NSLog(@"NSFileHandle Error: %@", errorNo); 
      return; 
     } 
    } 

    [socketHandle acceptConnectionInBackgroundAndNotify]; 


    [[NSNotificationCenter defaultCenter] addObserver:self 
     selector: @selector(processSocketData:) 
      name: NSFileHandleReadCompletionNotification 
     object: remoteFileHandle]; 

    // Send a message to the client, acknowledging that the connection was accepted 
    [remoteFileHandle writeData: [@"OK" dataUsingEncoding: NSASCIIStringEncoding]]; 

    [remoteFileHandle readInBackgroundAndNotify]; 
} 

/* 
Handle client data 
*/ 
- (void)processSocketData:(NSNotification *)note 
{ 
    NSData *data = [[note userInfo] 
        objectForKey:NSFileHandleNotificationDataItem]; 

    NSNumber* errorNo = [[note userInfo] objectForKey:@"NSFileHandleError"]; 
    if(errorNo) { 
     NSLog(@"NSFileHandle Error: %@", errorNo); 
     return; 
    } 

    // Do something here with your data 

    // search string for \n\n that terminates event 
    NSString* stringData = [[NSString alloc] initWithData: data encoding: NSASCIIStringEncoding]; 
    NSLog(@"data received: %@", stringData); 

    NSDictionary* lastEvent = nil; 

    NSRange range = [stringData rangeOfString: @"\n\n"]; 

    if (range.location != NSNotFound) { 
     NSArray* subStrings = [stringData componentsSeparatedByString:@"\n\n"]; 

     NSMutableArray* events = [[NSMutableArray alloc] init]; 

     [eventBuffer appendString: [subStrings objectAtIndex: 0]]; 

     // handle first event - could be in parts 
     NSDictionary * json = (NSDictionary*)[eventBuffer JSONValue]; 

     [events addObject:json]; 

     for(int i = 1; i < [subStrings count]-1; i++){ 
      NSString* subString = [subStrings indexOfObject:i]; 

      NSDictionary * eventJson = (NSDictionary*)[subString JSONValue]; 

      [events addObject:eventJson]; 
     } 

     // we have at least one event to draw here 

     for(NSDictionary* event in events){ 
      NSLog(@"event: %@", [event objectForKey:@"type"]); 
     } 

     lastEvent = [events lastObject]; 

     // clear eventBuffer 
     [eventBuffer setString:@""]; 

     // add end of data to eventBuffer? 
    }else { 
     [eventBuffer appendString:stringData]; 

    } 

    // check event if it is a program exit event then stop receiving data 

    if([[lastEvent objectForKey: @"type"] compare: @"exit"] != NSOrderedSame){ 
     // Tell file handle to continue waiting for data 
     [[note object] readInBackgroundAndNotify]; 
    }else { 


     NSLog(@"exit received stopping receiving data"); 
    } 

} 

Answer 1

我以前见过这个问题。
一旦读取完所有数据后，再进行一次“在后台接受连接”以进行另一轮读取数据。