[REBOL] Re: CGI: reading POST-method data with read-io
From: g:santilli:tiscalinet:it at: 24-Aug-2000 19:37
Hello [alex--pini--mclink--it]!
On 24-Ago-00, you wrote:
a> I've read the User's Guide, the old FAQs, the how-to and the
a> recent Networking chapter, but I still lack insight on the
a> inner workings of read-io. I can make conjectures, they may
a> even work, but I don't like that: in the long run, I could
a> accumulate all sorts of mistakes.
I hope I can help...
a> ---------- Buffer ----------
a> We need a buffer. If we need to read 2000 bytes, the buffer is
a> made 2002 bytes long with
a> data1: make string! 2002
(This is probably a bug. I think it was going to be fixed...)
a> I guess the extra 2 bytes are needed to store ancillary
a> information, but their content is not my concern, for now. Can
a> we make the buffer as in
a> data2: make string! 2000
You should be able to, but it creates problems if the length is a
multiple of 16. I had a lot of troubles because of this... :-)
a> or even
a> data3: copy ""
READ-IO is very low-level, and does not extend the string. Anyway,
since the new experimental release of core has asyncronous TCP
ports, READ-IO should no more be needed.
a> ---------- Correct buffer-length ----------
a> According to CGI quasi-official specs, once I've checked the
a> message body is in URL-encoded format, I must read no more
a> than CONTENT_LENGTH bytes from system/ports/input. So if I
a> want to go elegant and read *exactly* CONTENT_LENGTH bytes I
a> make my buffer exactly 2 bytes longer than that and use
a> read-io to read exactly CONTENT_LENGTH bytes, so I don't waste
a> memory in a prudent 128 MB buffer, right?
Yup.
a> ---------- Data readiness ----------
[...]
a> CONTENT_LENGTH is, say, 22000 bytes, what happens if I request
a> my 22000 bytes but only 1000 are available? Will read-io
a> return the 1000 bytes immediately (which means I have to do
Yes.
Regards,
Gabriele.
--
Gabriele Santilli <[giesse--writeme--com]> - Amigan - REBOL programmer
Amiga Group Italia sez. L'Aquila -- http://www.amyresource.it/AGI/
