从CFReadStream读取数据并将其转换为NSString

Question

我正在构建我的iPhone应用程序的问题。该应用程序向python服务器发送JSON请求，然后从服务器读取JSON响应。我有以下函数将数据发送到服务器并获取响应并将其放入NSData。 （我拿出了帖子的服务器地址）

+(NSData *)accessServer:(NSMutableDictionary *) dic needResponse:(BOOL) response
{
    // Conect to the server
    CFReadStreamRef readStream;
    CFWriteStreamRef writeStream;
    CFStringRef remoteHost = CFSTR("");
    CFStreamCreatePairWithSocketToHost(NULL, remoteHost, 5687, &readStream, &writeStream);
    CFWriteStreamOpen(writeStream);
    CFReadStreamOpen(readStream);

    // send data
    NSData *json = [NSJSONSerialization dataWithJSONObject:dic options:0 error:nil];
    NSString *jsonString = [[NSString alloc]initWithData:json encoding:NSUTF8StringEncoding];
    jsonString = [NSString stringWithFormat:@"%@%@", jsonString, @"\r\n\r\n"];
    UInt8 *writeBuf = (UInt8 *)[jsonString UTF8String];
    int writtenBytes = 0;
    int bytesToSend = (int)[jsonString lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
    while(writtenBytes < bytesToSend)
    {
        writtenBytes += CFWriteStreamWrite(writeStream, writeBuf, bytesToSend-writtenBytes);
    }
    NSLog(@"Done sending, Sent :%d Total: %d",writtenBytes,bytesToSend);
    CFWriteStreamClose(writeStream);
    if(response)
    {
        // get the return data
        uint8_t readData[10000];
        int readBytes = 1;
        int totalRead = 0;
        while(readBytes > 0)
        {
            readBytes = (int)CFReadStreamRead(readStream, readData, 10000);
            totalRead += readBytes;
        }
        CFReadStreamClose(readStream);
        return [[NSData alloc]initWithBytes:readData length:totalRead];
    }
    else
    {
        CFReadStreamClose(readStream);
        return nil;
    }
}

问题在于，当我尝试获取NSData并将其转换为NSString时，它的长度为0，NSData的长度为＆gt; 0.以下代码是我如何获取NSData并将其转换为NSString。

NSData *t = [Globals accessServer:getLocationData needResponse:TRUE];
NSString *tempString = [[NSString alloc]initWithData:t encoding:NSUTF8StringEncoding];

这个问题似乎发生在大约10％的时间。有时它不会发生一个小时，有时它会连续发生10次。任何帮助表示赞赏，如果您需要我可能忘记了的更多信息，请告诉我。