Essentially the problem that I am having is that my tcp/ip based server is randomly not receiving some of the packets I send. I'm sure that it's not actually random, but I have yet to figure out what is causing the issue. This exact code worked perfectly in the previous version of my app. Here is my code:
Initializing network connection:
- (void)initNetworkCommunication {
CFReadStreamRef readStream;
CFWriteStreamRef writeStream;
int randomPort = [self randomPort];
CFStreamCreatePairWithSocketToHost(NULL,(__bridge CFStringRef)kSERVER_ADDRESS, randomPort, &readStream, &writeStream);
inputStream = (__bridge NSInputStream *)readStream;
outputStream = (__bridge NSOutputStream *)writeStream;
[inputStream setDelegate:self];
[outputStream setDelegate:self];
[outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[outputStream open];
}
The function randomPort returns either 1244 or 1245 at random, which are port number references for the server. the constant kSERVER_ADDRESS is simply a string storing the server's address.
To send a packet I use this function:
- (void)sendPacket:(NSData *)packet {
[self initNetworkCommunication];
[outputStream write:[packet bytes] maxLength:[packet length]];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self performSelector:@selector(scheduleInThread:) onThread:[[self class] networkThread] withObject:nil waitUntilDone:YES];
});
}
Scheduling the input stream:
- (void)scheduleInThread:(id)sender {
[inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
[inputStream open];
}
And handling network events:
- (void)stream:(NSStream *)stream handleEvent:(NSStreamEvent)eventCode {
BOOL shouldClose = NO;
switch(eventCode) {
case NSStreamEventHasBytesAvailable:
{
NSLog(@"bytes available");
uint8_t *buffer = malloc(10000);
NSInteger len = [inputStream read:buffer maxLength:10000];
self.networkData = [[NSData alloc] initWithBytesNoCopy:buffer length:len];
NSString *dataString = [[NSString alloc] initWithData:self.networkData encoding:NSUTF8StringEncoding];
NSLog(@"%@", dataString);
NSLog(@"length: %li", len);
[self.delegate serverAgent:self didReceiveNetworkData:YES];
break;
}
case NSStreamEventNone:
{
break;
}
case NSStreamEventHasSpaceAvailable:
{
break;
}
case NSStreamEventEndEncountered:
{
shouldClose = YES;
[self closeThread];
break;
}
case NSStreamEventErrorOccurred:
{
isNetworkAvailable = NO;
shouldClose = YES;
[[NSNotificationCenter defaultCenter] postNotificationName:kNETWORK_UNAVAILABLE_NOTIFICATION object:nil];
break;
}
case NSStreamEventOpenCompleted: {
isNetworkAvailable = YES;
[[NSNotificationCenter defaultCenter] postNotificationName:kNETWORK_AVAILABLE_NOTIFICATION object:nil];
break;
}
}
if(shouldClose) {
[stream close];
}
}
I have verified that about 70% of the time the server does not receive the packet, and about 30% of the time the server receives the packet and everything works perfectly. I have also verified that it is not an issue of the port number, both ports are working fine. Additionally, no network error is occurring.Sometimes the server receives the packet after a long delay (15-20s) and sometimes the packet isn't received at all. If anyone could shed some light onto this issue it would be much appreciated. I definitely am a novice when it comes to using the tcp/ip protocol with iOS. Thank you in advance.
