Hi all
I just tried something that I did not think had a snowball's chance of
working, but to my surprise it did. I thought I would share it, partly
for interest, and partly in case anyone can foresee any problems with it.
I use ReportLab to generate pdf files. I do not write them to disk, but
use BytesIO to store them in memory. There are two main scenarios - send
an email and attach a pdf (which I have not addressed yet), and stream a
pdf via HTTP for display in a browser (which is the subject of this post).
I use asyncio, which accepts a request from a client and passes a
client_reader and a client_writer to my handler. This is how I handle a
pdf request at present -
with io.BytesIO() as pdf_fd:
await pdf_handler(pdf_fd)
pdf_fd.seek(0) # rewind
client_writer.write(pdf_fd.read())
client_writer.write(b'\r\n')
I actually write it in 'chunks', but omitted that to keep it simple.
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?
Thanks
Frank Millman
--
https://mail.python.org/mailman/listinfo/python-list
