正好遵循Apple的文档:https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Streams/Streams.html - 我无法让任何网络NSOutputStream 永远写入数据。它总是返回一个Apple的文档似乎不应该返回的数字(0 - Apple声称这是针对固定大小的流,而不是网络流?)。
所有Apple的示例代码都忽略了返回代码(似乎假设它是正面的 - 我在网上找到的很多样本都使用无符号类型!这是非常错误的:()。
我成功了:
...所有这些都有效,通过远程登录到IP地址+端口确认......
...但是,只要遵循Apple文档,就会出现可怕的错误:
void handleConnect (
CFSocketRef s,
CFSocketCallBackType callbackType,
CFDataRef address,
const void *data,
void *info
)
{
NSLog(@"handleConnect called with callbackType = %li", callbackType);
(myclass) server = (myclass*) info;
BOOL canAccept = callbackType & kCFSocketAcceptCallBack;
BOOL canWrite = callbackType & kCFSocketWriteCallBack;
BOOL canRead = callbackType & kCFSocketReadCallBack;
NSLog(@" ... acceptable? %@ .. readable? %@ .. writeable? %@", canAccept?@"yes":@"no", canRead?@"yes":@"no", canWrite?@"yes":@"no" );
if( canAccept)
{
NSLog(@"[%@] Accepted a socket connection from remote host. Address = %@", [server class], addressString );
/**
"which means that a new connection has been accepted. In this case, the data parameter of the callback is a pointer to a CFSocketNativeHandle value (an integer socket number) representing the socket.
To handle the new incoming connections, you can use the CFStream, NSStream, or CFSocket APIs. The stream-based APIs are strongly recommended."
*/
// "1. Create read and write streams for the socket with the CFStreamCreatePairWithSocket function."
CFReadStreamRef clientInput = NULL;
CFWriteStreamRef clientOutput = NULL;
// for an AcceptCallBack, the data parameter is a pointer to a CFSocketNativeHandle
CFSocketNativeHandle nativeSocketHandle = *(CFSocketNativeHandle *)data;
CFStreamCreatePairWithSocket(kCFAllocatorDefault, nativeSocketHandle, &clientInput, &clientOutput);
// "2. Cast the streams to an NSInputStream object and an NSOutputStream object if you are working in Cocoa."
// "3. Use the streams as described in “Writing a TCP-Based Client.”
self.outputBuffer = [NSMutableData dataWithData:[@"Hello" dataWithEncoding:NSUTF8StringEncoding]];
self.outputBytesWrittenRecently = 0;
((NSOutputStream*)output).delegate = self;
[((NSOutputStream*)output) scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[((NSOutputStream*)output) open]; // MUST go last, undocumented Apple bug
}
}
...和委托方法:
-(void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode
{
BOOL streamOpened = eventCode & NSStreamEventOpenCompleted;
BOOL streamReadyToWrite = eventCode & NSStreamEventHasSpaceAvailable;
BOOL streamReadyToRead = eventCode & NSStreamEventHasBytesAvailable;
BOOL streamEnded = eventCode & NSStreamEventEndEncountered;
BOOL streamErrored = eventCode & NSStreamEventErrorOccurred;
if( streamReadyToWrite )
#define C_BUFFER_IN_MEMORY_SIZE_WRITE ( 4096 ) // Apple vaguely recommends 4k, but I tried numbers down to 100 with no effect
uint8_t extraCBufferNSStreamSucks[ C_BUFFER_IN_MEMORY_SIZE_WRITE ];
NSRange rangeOfBytesToAttemptToWriteNext = { self.outputBytesWrittenRecently, MIN( C_BUFFER_IN_MEMORY_SIZE_WRITE, self.outputBuffer.length - self.outputBytesWrittenRecently) };
[self.outputBuffer getBytes:&extraCBufferNSStreamSucks range:rangeOfBytesToAttemptToWriteNext];
NSLog(@"About to write data to stream, this might block...");
NSInteger amountWritten = [self.outputS write:extraCBufferNSStreamSucks maxLength:C_BUFFER_IN_MEMORY_SIZE_WRITE];
NSLog(@"...finished write data to stream, it might have blocked");
if( amountWritten > 0 )
{
self.outputBytesWrittenRecently += amountWritten;
NSRange totalWrittenRange = { 0, self.outputBytesWrittenRecently };
NSLog(@"Written %i bytes: %@", amountWritten, [[[NSString alloc] initWithData:[self.outputBuffer subdataWithRange:totalWrittenRange] encoding:NSUTF8StringEncoding] autorelease] );
if( self.outputBytesWrittenRecently == self.outputBuffer.length )
{
NSLog(@"Finished writing data!");
}
}
else
NSLog(@"ERROR: failed to write bytes to stream (bytes written = %i)", amountWritten);
}
答案 0 :(得分:1)
啊!未记载,但是......如果您的NSStream实例变为nil,而不是返回错误,Apple会返回成功 - 但是然后返回0表示写入的字节数。
就我而言,init方法中的拼写错误意味着我用nil覆盖了新捕获的NSOutputStream和NSInputStream。
哎呀。