xcode iOS 中的 TCP 套接字编程。服务器客户端响应
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TCP Socket Programming in iOS. Server Client Response
提问by iPhany
I'm almost done with this task but i'm stuck a point due to which i'm getting partial result. I have server(linux or windows) and client(iOS) between which TCP IP socket connection exist. I have used form load in my iphone simulator where the connection between server and iphone happens automatically as the application opens. Server send the data back what ever I send on simulator and print it in log. But i'm not able to exactly receive the whole response. For "Innovations" I receive maybe just "in" or "Innova"etc.. Below are the code snippets.
我几乎完成了这项任务，但由于我得到了部分结果，我陷入了困境。我有服务器（linux 或 windows）和客户端（iOS），它们之间存在 TCP IP 套接字连接。我在我的 iphone 模拟器中使用了表单加载，其中服务器和 iphone 之间的连接在应用程序打开时自动发生。服务器将数据发回我在模拟器上发送的内容并将其打印在日志中。但我无法完全收到整个回复。对于“创新”，我收到的可能只是“in”或“Innova”等。下面是代码片段。
void TCPClient()
{
CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault, host, port, &readStream, &writeStream);
[NSThread sleepForTimeInterval:2]; //Delay
CFWriteStreamSetProperty(writeStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
if(!CFWriteStreamOpen(writeStream))
{
NSLog(@"Error Opening Socket");
}
else
{
UInt8 buf[] = "Innovations";
int bytesWritten = CFWriteStreamWrite(writeStream, buf, strlen((char*)buf));
NSLog(@"Written: %d", bytesWritten);
}
CFReadStreamSetProperty(readStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
if(!CFReadStreamOpen(readStream))
{
NSLog(@"Error reading");
}
else
{
UInt8 bufr[15];
int bytesRead = CFReadStreamRead(readStream, bufr,strlen((char*)bufr));
NSLog(@"Read: %d", bytesRead);
NSLog(@"buffer: %s", bufr);
}
}
Notice in the read I did change the array size. But I still get the error. Same in the case of IBAction of a button. Even in that for every click i'm sending a data and i'm not getting the response of the same data.
请注意，在读取中我确实更改了数组大小。但我仍然收到错误消息。按钮的 IBAction 也是如此。即使每次点击我都会发送数据，但我没有得到相同数据的响应。
Can valuable suggestion???
可以提出宝贵意见吗？？？
回答by Martin R
One error is that
一个错误是
int bytesRead = CFReadStreamRead(readStream, bufr,strlen((char*)bufr));
should be
应该
int bytesRead = CFReadStreamRead(readStream, bufr, sizeof(bufr));
The last parameter of CFReadStreamReadis the capacityof the read buffer and determines the maximum number of bytes read. strlen((char*)bufr)is the lengthof the string currently in the buffer. You should also NULL-terminat the string in bufrbefore printing it.
的最后一个参数CFReadStreamRead是读取缓冲区的容量，决定了读取的最大字节数。strlen((char*)bufr)是当前缓冲区中字符串的长度。您还应该bufr在打印之前以NULL 结尾的字符串。
With this modification, your program might work with short strings. But there will be problems as soon as you try to send/receive larger amounts of data.
通过这种修改，您的程序可能会使用短字符串。但是，一旦您尝试发送/接收大量数据，就会出现问题。
A socket write can write less bytes than you asked it to, and a socket read can return less bytes than you requested.
套接字写入可以写入比您要求的更少的字节，而套接字读取可以返回比您请求的更少的字节。
Have a look at the Stream Programming Guidewhich describes how to register the socket streams with the runloop and handle stream events asynchronously.
查看Stream Programming Guide，它描述了如何使用 runloop 注册套接字流并异步处理流事件。
