Question

I have the following code written in Objective-C that writes data to a socket. The server is running node.js on top of Ubuntu:

NSString *url = @"anIPAddress";        
CFReadStreamRef readStream;
CFWriteStreamRef writeStream;            
CFStreamCreatePairWithSocketToHost(NULL, (CFStringRef)url, 9000, &readStream, &writeStream);
self.inputStream = (NSInputStream *)readStream;            
self.outputStream = (NSOutputStream *)writeStream;
[self.inputStream setDelegate:self];            
[self.outputStream setDelegate:self];            
[self.inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];            
[self.outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];            
[self.inputStream open];            
[self.outputStream open];

I am able to connect to the server and send information. However I noticed the connection times out after a few minutes (I think 5 minutes or so?). How can I keep this connection alive? I know there is a disconnect because the same thing happens if I connect to the server under Terminal, I have to keep that connection alive. I imagine the same thing is happening in my code. Thanks for your help!

Answer 1

I found how to do this. Since the server is running node.js, I used

socket.setKeepAlive(true, 2000);

And in this way node keeps each socket open. The default is false, so this is why it was timing out. I hope this is useful to other people. Thank your for your responses, I think keeping a heartbeat (keep-alive) is also a good idea, but with this native approach node takes care of it.