On 28 September 2014 00:00, Antoine Pitrou <anto...@python.org> wrote: > > Hi, > > Robert Collins <robertc@...> writes: >> >> https://github.com/python-web-sig/wsgi-ng/issues/5 >> >> tl;dr - we don't specify whether read(size) has to return size bytes >> or just not more than size, today. the IO library is clear that >> read(n) returns up to n, and also offers read1 that guarantees only >> one read call. > > I think you've got things mixed up. There are two different things in > "the IO library" (which is really the 3.x IO stack): > > * buffered binary I/O has read(n) and read1(n): > - read(n) will block until n bytes are received (except for non-blocking > fds) > - read1(n) will issue at most one system call and can return fewer than > n bytes > > * raw binary I/O only has read(n): > - read(n) will issue at most one system call and can return fewer than > n bytes > > So, depending on which layer you are placing yourself on, one or the > other of your statements is wrong.
Ugh. Thanks! > That said, it would be reasonable for WSGI to expose the raw I/O layer, > IMHO. "Prettifying" libraries can wrap it inside a BufferedReader if > they like. We often can't expose the real underlying socket, but having the semantics of raw binary I/O for the file-like things we do expose makes more sense to me. > Note that I once proposed generalized prefetching on I/O streams, but > it was rejected: > https://mail.python.org/pipermail/python-ideas/2010-September/008179.html > (skip to the prefetch() proposal) > > It was in the context of improving streamed unpickling, which is > a problem a bit similar - but less horrible - to JSON unserializing; > since then, the problem was solved in a different way by adding a > framing layer to pickle protocol 4 :-). BufferedReader solves this well though, doesn't it? -Rob -- Robert Collins <rbtcoll...@hp.com> Distinguished Technologist HP Converged Cloud _______________________________________________ Web-SIG mailing list Web-SIG@python.org Web SIG: http://www.python.org/sigs/web-sig Unsubscribe: https://mail.python.org/mailman/options/web-sig/archive%40mail-archive.com
