On 2020-01-21 6:17 PM, Maxime S wrote:
Hi,
Le ven. 17 janv. 2020 à 20:11, Frank Millman <fr...@chagford.com> a écrit :
It works perfectly. However, some pdf's can be large, and there could be
concurrent requests, so I wanted to minimise the memory footprint. So I
tried passing the client_writer directly to the handler -
await pdf_handler(client_writer)
client_writer.write(b'\r\n')
It works! ReportLab accepts client_writer as a file-like object, and
writes to it directly. I cannot use chunking, so I just let it do its
thing.
Can anyone see any problem with this?
If the socket is slower than the PDF generation (which is probably always
the case, unless you have a very fast network), it will still have to be
buffered in memory (in this case in the writer buffer). Since writer.write
is non-blocking but is not a coroutine, it has to buffer. There is an
interesting blog post about that here that I recommend reading:
https://lucumr.pocoo.org/2020/1/1/async-pressure/
Thanks for the comments and for the link - very interesting.
Following the link led me to another essay -
https://github.com/guevara/read-it-later/issues/4558
I only understood a portion of it, but it forces you to question your
assumptions, which is always a good thing.
Frank
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