curl-library
Re: Problem posting large data using libcurl
Date: Thu, 15 Jan 2015 16:01:46 +0530
On Thu, Jan 15, 2015 at 2:59 PM, Dan Fandrich <dan_at_coneharvesters.com>
wrote:
> On Thu, Jan 15, 2015 at 10:55:12AM +0530, Heena Sirwani wrote:
> > I am using libcurl in C with the mutli socket interface along with
> libuv. I add
> > easy handles to the multi handle for each request and start the libuv
> event
> > loop together with adding sockets for polling for appropriate activity
> to libuv
> > poll interfaces.
> >
> > The problem is when I post data > 5k to the server. I don't seem to get
> any
>
> libcurl starts doing 100 Continue at about that threshold, IIRC, and some
> old
> servers don't handle that well.
>
Yes I read about that.
>
> > response. When I check this at the server side, the server seems to be
> sending
> > a 408 response meaning it did not receive the request body within the
> interval
> > it was prepared to wait. I tried increasing the request time out value
> to 100
> > seconds (I guess that should suffice). But the problem persists. I also
> don't
> > get any response at the client side ( I assume that the client keeps
> sending
> > data event when the server has closed the connection and the server
> sends the
> > reset flag to clear the input buffers at the client side that contains
> the
> > unacknowledged responses and they are cleared even before the client
> reads
> > them). I have also reset the Expect: 100 continue header.
>
> Ah, that would have been my suggestion. But how did you do that? Forcing a
> HTTP
> 1.0 connection would guarantee it, and is another thing to try if you
> haven't
> already.
>
I reset it using headers = curl_slist_append(headers, "Expect:");
I tried forcing the connection to http 1.0 but that also does not work.
>
> > Also when I do a post with the same amount of data using only easy
> handles
> > (blocking), I get the response within 3 seconds. The size of the data
> after
> > which I do not get any response also varies from machine to machine ( on
> > another machine I do not get a response for data > 3k). I am assuming
> that
> > libcurl with libuv is slowing down the process of writing data to send
> to the
> > server. Also the event loop runs in a separate thread from where I
> actually add
> > handles to the multi interface.
>
> That's a no-no. libcurl is thread safe only if any given handle is
> manipulated
> strictly within a single thread. Read the thread safety sections of the
> manual
> again.
>
I did read about it and hence I have implemented thread synchronization
when I add handles and when I perform action on the sockets i.e. when
libcurl is traversing the handle tree.
>
> >>> Dan
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Received on 2015-01-15