27.07.2009, в 12:35, Maciej Stachowiak написал(а):
However, I do not think that raising an exception is an appropriate
answer. Often, the TCP implementation takes a part of data given to
it, and asks to resubmit the rest later. So, just returning an
integer result from send() would be best in my opinion.
With WebSocket, another possibility is for the implementation to
buffer pending data that could not yet be sent to the TCP layer, so
that the client of WebSocket doesn't have to be exposed to system
limitations. At that point, an exception is only needed if the
implementation runs out of memory for buffering. With a system TCP
implementation, the buffering would be in kernel space, which is a
scarce resource, but user space memory inside the implementation is
no more scarce than user space memory held by the Web application
waiting to send to the WebSocket.
I agree that this will help if the application sends data in burst
mode, but what if it just constantly sends more than the network can
transmit? It will never learn that it's misbehaving, and will just
take more and more memory.
An example where adapting to network bandwidth is needed is of course
file uploading, but even if we dismiss it as a special case that can
be served with custom code, there's also e.g. captured video or audio
that can be downgraded in quality for slow connections.
- WBR, Alexey Proskuryakov
