curl-library
Re: Differences between the buffer-oriented curl_fromadd() parameters
Date: Tue, 1 Oct 2002 20:12:11 +0200 (CEST)
Hi Daniel!
Thanks a lot for your quick reply!
What I'm actually trying to do is that I want to upload a buffer using
HTTP POST request. Basically, the buffer is similar to what's provided in
the example section of the man page:
char htmlbuffer[] = "<HTML>test buffer</HTML>";
but it's longer and contains XML instead of HTML data.
On Tue, 1 Oct 2002, Daniel Stenberg wrote:
> [...]
> I know the curl_formadd man page isn't very well structured. I'll welcome all
> kinds of improvements anyone can provide.
I would be willing to provide improvements, but first I've to understand
the matter myself ;-)
> [...]
> PTRCONTENTS means that you only pass the pointer to libcurl, and it'll refer
> to the same data you pointed to. COPYCONTENTS will make libcurl copy that
> data, and thus you can remove it immediately after having called
> curl_formadd(), if that's what you want.
Ok, so that covers the difference between PTRCONTENTS and COPYCONTENTS.
> Needless to say, PTRCONTENTS will be a lot faster and less resourse-hungry
> especially if you plan to send away large chunks of data.
Thanks a lot for that hint.
> [...]
> BUFFER sets a name for the buffer upload. This name is what the "filename"
> will be set to, as this is a "file upload" kind of form.
Why is there another CURLFORM_* option for this purpose? Why can't I just
CURLFORM_COPYNAME for that? I had the impression CURLFORM_COPYNAME is the
CURLFORM option used to set field names. Or am I wrong?
> [...]
> > curl_formadd(&post, &last,
> > CURLFORM_COPYNAME, "name",
> > CURLFORM_COPYCONTENTS, "data",
> > CURLFORM_END);
>
> The only difference here is that this COPYCONTENTS copies the data part too.
Ok. So, in contrast to the example using CURLFORM_PTRCONTENTS, this
example will contain a field name whose data is contained in a buffer
named "data", whereas in the example using CURLFORM_PTRCONTENTS, the field
data for the field named "name" is just the string "data". Right?
> > curl_formadd(&post, &last,
> > CURLFORM_COPYNAME, "name",
> > CURLFORM_BUFFERPTR, "data",
> > CURLFORM_END);
>
> This makes it a file upload part, as that's what BUFFERPTR implies. I believe
> this particular use of the function will return an error code, as you haven't
> provided a BUFFER to name the file in this faked file upload.
Ok. I now understand what's wrong with the example given above.
The reason why all of this seems pretty confusing to me is that different
CURLFORM_* options are used to set the values of certain field name. Why
wasn't something like a CURLFORM_COPYNAME/CURLFORM_COPYVALUE pair
introduced, allowing you to set CURLFORM_COPYNAME to "filename" and
CURLFORM_COPYVALUE to "blah.txt"? I admit that this would probably not be
as flexible as the current approach, but (at least in some cases) a bit
more obvious.
> I hope this mail has clarified it somewhat.
Partly, yes :-)
Thanks a lot for taking your time to answer my questions.
Kind regards,
Holger
-------------------------------------------------------
This sf.net email is sponsored by: DEDICATED SERVERS only $89!
Linux or FreeBSD, FREE setup, FAST network. Get your own server
today at http://www.ServePath.com/indexfm.htm
Received on 2002-10-01