NSOutputStream 发送旧值 - Objective C

Posted 2023-03-08

【中文标题】NSOutputStream 发送旧值 - Objective C

【英文标题】：NSOuputStream sends Old Value - Objective C

【发布时间】：2014-08-18 07:16:41

【问题描述】：

我创建了用于发送/接收值的套接字的代码。我都做了。第一次效果很好。我面临的问题是每当我第二次发送新值时，旧值都会被传递。就像，我第一次向套接字发送 0 值时，套接字端的日志文件在日志文件中接收为“0”，并且我从服务器接收到数据，它运行良好。但是当我将另一个值（如“2”）发送到套接字时，但服务器套接字在日志文件中接收先前的值作为“0”。我无法发送新值。

我的代码是

Appdelegate.h

@property (strong) NSInputStream *inputStream;
@property (strong) NSOutputStream *outputStream;

- (void) applicationDdifinishLaunching....
[self initNetworkCommunication:@"192.168.1.38"];

Appdelegate.m

- (void) initNetworkCommunication:(NSString *) getIp 
NSLog(@"GETIP = %@",getIp);
CFStringRef aCFString = (__bridge CFStringRef)getIp;

CFReadStreamRef readStream;
CFWriteStreamRef writeStream;
CFStreamCreatePairWithSocketToHost(NULL, aCFString, 1500, &readStream, &writeStream);
CFReadStreamSetProperty(readStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
CFWriteStreamSetProperty(writeStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);

NSInputStream *inStream = (__bridge NSInputStream *) readStream;
NSOutputStream *outStream = (__bridge NSOutputStream *) writeStream;

[inStream setDelegate:self];
[outStream setDelegate:self];
[inStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[outStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[inStream open];
[outStream open];

self.inputStream = inStream;
self.outputStream = outStream;
[self performSelectorInBackground:@selector(StartDatatoServer:) withObject:@"0"];




- (void) StartDatatoServer:(id) get

NSString *command = [NSString stringWithFormat:@"%@",get];
//NSData *datafixed = [[command stringByAppendingString:@"\r\n"] dataUsingEncoding:NSUTF8StringEncoding];
NSMutableData *data = (NSMutableData *)[[command stringByAppendingString:@"\r\n"] dataUsingEncoding:NSUTF8StringEncoding];
unsigned long length = [data length];

uint8_t *readBytes = (uint8_t *) [data bytes];
uint8_t buffer[length];
(void)memcpy(buffer, readBytes, length);
length = [outputStream write:(const uint8_t *)buffer maxLength:length];
if (-1 == length) 
        NSLog(@"Error writing to stream %@: %@", outputStream, [outputStream streamError]);
 else 
        NSLog(@"Wrote %ld bytes to stream %@.", (long)length, outputStream);

[self writeLogFile:command TypeName:@"ServerStart"];





- (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent  
switch (streamEvent) 
    case NSStreamEventOpenCompleted:
    
        if ([theStream isKindOfClass:[inputStream class]]) 
            NSLog(@"Input stream opened");
         else 
            NSLog(@"output stream opened");
        
        break;
    
    case NSStreamEventHasSpaceAvailable:
        NSLog(@"NSEvethaspcape");
        break;
    case NSStreamEventHasBytesAvailable:
        // Listening Server Acknowledgement
        NSLog(@"NSStreamEventHasBytesAvailable");
        if (theStream == inputStream) 
        
        break;
    case NSStreamEventErrorOccurred:
         NSLog(@"NSStreamEventErrorOccurred");
        // When disconnect or Error occured between socket & server
        break;
    case NSStreamEventEndEncountered:
        // Occur when Server is Closed
        NSLog(@"NSStreamEventEndEncountered");
        [theStream close];
        [theStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
        theStream = nil;
        break;
    default:
        NSLog(@"Unknown event");

在Windowcontroller.h中

anObject = @"2";

-(void) LoginConnectionProcess:(id)anObject


AppDelegate *appDelegate = (AppDelegate *)[[NSApplication sharedApplication] delegate];
appDelegate.inputStream.delegate = self;
appDelegate.outputStream.delegate = self;

NSString *command = [NSString stringWithFormat:@"%@",anObject];
NSMutableData *data = (NSMutableData *)[[command stringByAppendingString:@"\r\n"] dataUsingEncoding:NSUTF8StringEncoding];
unsigned long length =
[data length];
NSLog(@"anOjbe= %@",command);
uint8_t *readBytes = (uint8_t *) [data bytes];
uint8_t buffer[length];
(void)memcpy(buffer, readBytes, length);
length = [appDelegate.outputStream write:(const uint8_t *)buffer maxLength:length];
if (-1 == length) 
    NSLog(@"Errors writing to stream %@: %@", appDelegate.outputStream, [appDelegate.outputStream streamError]);
 else 
    NSLog(@"Wrotes %ld bytes to stream %@.", (long)length, appDelegate.outputStream);




- (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent

switch (streamEvent) 
    case NSStreamEventOpenCompleted:
        NSLog(@"ConnectionOpened");
        break;
    case NSStreamEventHasSpaceAvailable:
        NSLog(@"NSStreamEventHasSpaceAvailable");
        break;
    case NSStreamEventHasBytesAvailable:
    
        NSLog(@"NSStreamEventHasBytesAvailable");
        if (theStream == appDelegate.inputStream) 

        
        break;
    
    case NSStreamEventErrorOccurred:
        break;
    case NSStreamEventEndEncountered:
        [theStream close];
        [theStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
        theStream = nil;
        break;
    default:
        NSLog(@"Unknown Events");

每当我第二次调用时，流“NSStreamEventHasSpaceAvailable”函数只会触发。但从未调用过“NSStreamEventHasBytesAvailable”函数。我在这里缺少/问题。 等待您的回复。 任何帮助。提前致谢。

【问题讨论】：

代码看起来很烂。为什么要重置流代表？为什么第二个代码片段不使用StartDatatoServer:？当您可以直接在 NSData 对象中轻松访问字节时，为什么要将 NSData 对象复制到缓冲区？

@***foe 那么我如何访问 NSOuputstream 来发送数据，并且需要在打开套接字时立即发送数据

任何想要发送数据的代码都可以调用StartDataToServer: 并与流交互。

@***foe 好的。我将数据作为“0”发送到服务器，当连接打开时，我将该代码替换为“NSStreamEventOpenCompleted”函数。还是一样的工作。我只是第一次打电话。我有一个疑问。你能澄清一下，那个函数经常再次调用吗？

@***foe 我再次使用相同的代码，输出相同。 Here

【参考方案1】：

我刚刚调用了下面的代码，它会被刷新

NSString *command = [NSString stringWithFormat:@"%@\r",username.StringValue];
NSData *data = [command dataUsingEncoding:NSUTF8StringEncoding];
[outputStream write:[data bytes] maxLength:[data length]];