[Python-ideas] PEP 3156: Transport.sendfile

Fri Jan 25 21:04:24 CET 2013

On Fri, Jan 25, 2013 at 10:11 AM, Nikolay Kim <fafhrd91 at gmail.com> wrote:
>> On Jan 25, 2013, at 10:08 AM, Guido van Rossum <guido at python.org> wrote:
>> On Fri, Jan 25, 2013 at 10:03 AM, Nikolay Kim <fafhrd91 at gmail.com> wrote:
>>>>> I think Transport needs 'sendfile' api, something like:
>>>> @tasks.coroutine
>> def sendfile(self, fd, offset, nbytes):
>> ….
>>>> otherwise it is impossible to implement sendfile without breaking
>> transport encapsulation
>>> Really? Can't the user write this themselves? What's wrong with this:
>> while True:
> data = os.read(fd, 16*1024)
> if not data: break
> transport.write(data)
>> (Perhaps augmented with a way to respond to pause() requests.)
>>> i mean 'os.sendfile()', zero-copy sendfile.
>
I see (http://docs.python.org/dev/library/os.html#os.sendfile).
Hm, that function is so platform-specific that we might as well force users
to do it this way:
sock = transport.get_extra_info("socket")
if sock is not None:
 os.sendfile(sock.fileno(), ......)
else:
 <use write() like I suggested above>
-- 
--Guido van Rossum (python.org/~guido)
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