iOS：使用CFStreamCreatePairWithSocketToHost的套接字网络基础_app

概述用例我正在使用套接字使用CFStreamCreatePairWithSocketToHost()发送和接收数据,并试图在发送多组数据(即不仅仅是1个请求)时如何完成此 *** 作. 问题目前我可以发送数据并接收响应(即1次往返).但是,在我发送outputStream中的所有数据后,流被关闭(即接收NSStreamEventEndEncountered). 题所以问题是,当我想发送多个数据请求时会发用例

我正在使用套接字使用CFStreamCreatePairWithSocketToHost()发送和接收数据,并试图在发送多组数据(即不仅仅是1个请求)时如何完成此 *** 作.

问题

目前我可以发送数据并接收响应(即1次往返).但是,在我发送outputStream中的所有数据后,流被关闭(即接收NsstreamEventEndEncountered).

题

所以问题是,当我想发送多个数据请求时会发生什么？

>每次要发送新数据对象时,是否设置了新套接字？
>我是否必须重置outputStream并发送更多数据.

码

大部分代码来自Cocoa Streams Documentation：

- (voID)vIEwDIDLoad {    [super vIEwDIDLoad];    // Do any additional setup after loading the vIEw,typically from a nib.    _data = [[NSMutableData alloc] init];    [self initNetworkCommunication];    [self sendString:@"Hello World!"];}- (voID)initNetworkCommunication {    CFReadStreamRef readStream;    CFWriteStreamRef writeStream;    CFStreamCreatePairWithSocketToHost(NulL,(CFStringRef)@"123.456.0.0",1234,&readStream,&writeStream);    inputStream = (NSinputStream *)readStream; // ivar    [inputStream setDelegate:self];    [inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];    [inputStream open];    outputStream = (NSOutputStream *)writeStream; // ivar    [outputStream setDelegate:self];    [outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];    [outputStream open];}- (voID)sendString:(Nsstring *)string {    NSData *data = [[NSData alloc] initWithData:[string dataUsingEnCoding:NSASCIIStringEnCoding]];    [_data appendData:data];    [data release];}- (voID)stream:(Nsstream *)theStream handleEvent:(NsstreamEvent)streamEvent {    NSLog(@"stream event %u",streamEvent);    switch (streamEvent) {        case NsstreamEventopenCompleted:            NSLog(@"Stream opened");            break;        case NsstreamEventHasspaceAvailable: {            uint8_t *readBytes = (uint8_t *)[_data mutableBytes];            readBytes += byteIndex; // ivar            int data_len = [_data length];            unsigned int len = ((data_len - byteIndex >= 1024) ? 1024 : (data_len - byteIndex));            uint8_t buf[len];            (voID)memcpy(buf,readBytes,len);            len = [(NSOutputStream *)theStream write:(const uint8_t *)buf maxLength:len];            NSLog(@"Sending buffer of len: %d",len);            byteIndex += len;            break;        }        case NsstreamEventHasBytesAvailable:            if (theStream == inputStream) {                uint8_t buffer[1024];                int len;                while ([inputStream hasBytesAvailable]) {                    len = [inputStream read:buffer maxLength:sizeof(buffer)];                    if (len > 0) {                        Nsstring *output = [[Nsstring alloc] initWithBytes:buffer length:len enCoding:NSASCIIStringEnCoding];                        if (nil != output) {                            NSLog(@"server saID: %@",output);                        }                    }                }                [self sendString:@"Another Test"];            }            break;        case NsstreamEventErrorOccurred:            NSLog(@"Can not connect to the host!");            break;        case NsstreamEventEndEncountered:            NSLog(@"Closing stream...");            [theStream close];            [theStream removeFromrunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];            [theStream release];            theStream = nil;            break;        default:            NSLog(@"UnkNown event");    }}

响应：

2012-08-15 08:16:30.896 Sockets[34836:f803] Opened input stream.2012-08-15 08:16:30.898 Sockets[34836:f803] Opened output stream.2012-08-15 08:16:30.899 Sockets[34836:f803] Sending buffer of len: 122012-08-15 08:16:30.900 Sockets[34836:f803] Sending buffer of len: 02012-08-15 08:16:30.901 Sockets[34836:f803] Closing output stream.2012-08-15 08:16:30.939 Sockets[34836:f803] server saID: Hello World!

请注意,在发送数据后,outputStream流将关闭.我尝试在[self sendString：@“Another Test”]之前重新启动outputStream.我也试过了IDz的回答.

根据文档,我相信len：0的发送缓冲区是我的问题.

If the delegate receives an NsstreamEventHasspaceAvailable event and
does not write anything to the stream,it does not receive further
space-available events from the run loop until the NSOutputStream
object receives more bytes. When this happens,the run loop is
restarted for space-available events.

但是,文档没有说明在到达流末尾时关闭流.所以我很困惑……

解决方法套接字是连接两个程序的双向流,可能在两台不同的计算机上.它只是将您在一端写入的数据传输到另一端进行读取.它在数据中不强制执行任何结构,并且不了解有关请求或响应的任何信息.

CFStreamCreatePairWithSocketToHost API将单个连接拆分为两个独立的流 – 一个可以读取,另一个可以写入.这是一个很好的接触,底层套接字API只使用一个文件描述符进行读取和写入,这可能会让人非常困惑.

连接保持打开,直到一侧关闭插座.还有可能仅在一个方向上关闭插座.也可以仅在一个方向上关闭连接.如果遥控器关闭它的读取流,您的写入流将被关闭,反之亦然.