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Re: libcurl, squid proxy, failing multipart post

From: Ralph Mitchell <>
Date: Mon, 2 May 2005 10:25:46 -0500

First off, would it be possible for you to update to the latest
version, which is 7.13.2?? The one you're using dates back to March
2004. Source is here:

The ChangeLog (linked in the Related box, top right of the above page)
shows a lot of changes. You may be tripping a bug that's already been

Ralph Mitchell

On 5/2/05, <> wrote:
> first, thanks for libcurl. i had been beating my head against libwww for a
> couple weeks, when i found libcurl. much easier to use, and it actually
> seems to work :)
> now, my problem:
> C app that multipart posts a memory buffer as if it were a file upload,
> along with a couple short (<20 chars) textual variables. i have installed
> a call-back for libcurl to write to, and i can post and receive the
> response into memory just fine. all is well, until i try to pass thru a
> squid proxy.
> the setup: the posting app (using libcurl 7.11.1) and the http server
> (apache 2.0.x/modperl 1.99.x) are both on my desktop machine. the squid
> proxy is another machine on the same subnet. if i use mozilla from the
> app/server machine to post the same data to the same url as my app, it
> works. if i use libcurl in my app, it times out.
> i take tcpdump on the proxy, for all packets from the app/server machine.
> what i see is:
> ******* working mozilla **************
> mozilla sends http headers and post contents to proxy in 4 sequential
> packets. (squid ACK after each). the http headers are split across the
> first two packets. it does not use the Expect: header. it is an http 1.1
> post.
> then, squid opens a connection back to port 80, and sends the request in
> three packets quickly, the 3 ACKs appear to come back from apache after
> the last. the headers are all in the first packet, the post body is in
> two, larger segments, but is otherwise the same. it is an http 1.0 post.
> apache returns 200 to squid, the connection is torn down. this is http 1.1
> squid returns 200 to the app, the connection is torn down. this is http
> 1.0
> ********** non-working my app **************
> app sends http headers in a single packet, gets an ACK. the post body is
> never sent. I do not use the Expect: header.
> squid opens a connection to post 80, sends the headers, gets an ack.
> then we wait. app times out, and tears down connection to squid.
> squid tears down connection to httpd. httpd returns 200 OK during the
> teardown, and squid sends RST.
> *********************
> ok, so i am sure this is something i am doing, but it looks like even
> though i have Expect: turned off, libcurl is still waiting instead of
> sending the post body. i have searched around quite a bit, but did not see
> any answers.
> things to try? suggestions?
> thanks for any help you can give.
> allan
Received on 2005-05-02