Re: [Opentnl-general] Problem with large data buffers ?

[Ben G. <be...@ga...>]

Ivan Vorobeychyk wrote:

>Hi.
>Thanks for this magic library - very impressive, especially RPCs.
>I'm new to OpenTNL, so please, correct me, if I'm wrong.
>I'm trying to send big data chunk, using ByteBufferPtr as parameter
>in one of RPCs. It works fine for buffers<1500 Bytes but fails for larger
>data buffers. I found that TNL uses PacketStream with internal
>buffer of 1500 Bytes to send data, but I was really wondered that TNL
>can't break large buffer to small packets.
>  
>
Hi Ivan,

As it happens, you have to break your own data into chunks. TNL doesn't 
try to hide the nature of the transport from you, so as a result it 
won't work behind the scenes to allow you to do things like span data 
over multiple packets. In general for a realtime network connection 
doing that is a bad idea - if you get half of an update and the other 
half gets stalled somewhere out in the internet, then you might be in a 
great deal of trouble till it gets resolved!

If you're trying to transfer large buffers in a non-realtime setting, 
then the easiest thing to do is cut the buffer up into, say, 300-400 
byte chunks and send it by a series of guaranteed RPC calls or events. 
I've implemented some file transfer apps this way; it's quick and easy. 
If it's a very large file you might want to only try to keep a dozen or 
so calls/events in flight, and wait till one has been received before 
sending the next.

Regards,
Ben Garney