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Re: CURLOPT_WRITEFUNCTION function getting called multiple time even the complete http response body is only 2155 bytes

From: ( \\/\\/|||\ <>
Date: Sat, 20 Jun 2015 16:05:28 -0300

Libcurl is just a wrapper around OpenSSL, and forgive me if I'm wrong, but
it looks like the only original functionality libcurl has is to verify
certificates (which doesn't work that well either... try verifying yahoo's

I had this same problem using libcurl and their awkward, over complicated
callback scheme.

OpenSSL has sockets more or less identical to send()/recv() API, so you can
read data directly from a socket, and no need to deal with header callback,
body callback, write callback, blah blah etc.

IMHO - while correct to libcurl's functions Ray Satiro's answer highlights
how incredibly over complicated such simple tasks are w/libcurl.

This code has faults but is enough to get you started. You can get size,
etc straight from the socket.

If you want to roll code yourself to verify certs, you can find a lot of
info/links to various code samples on OpenSSL's site.

On Fri, Jun 19, 2015 at 8:12 PM, Daniel Stenberg <> wrote:

> On Fri, 19 Jun 2015, Ganesh Nikam wrote:
> 1. What do you mean by "as much as possible" here ? how libcurl decides
>> it ?
> It depends completley on what it receives. For every recv() call (and some
> other details Jay mentioned), libcurl will call the callback to deliver
> data.
> 2. In my case, my complete http response boby is of 2155 bytes. For such
>> small response also libcurl breaks the message in two callbacks. First with
>> 1295 byte and other is 860 byte. What could be the reasons for
>> calling callback two times for such small message size?
> Most probably libcurl received the data in two different recv() calls.
> 3. I want to get the complete http response in single write_callbck
>> function.
> libcurl doesn't work like that.
> is there is any way to get the complete size of the http response ?
> Sure, for example like this:
> My http server sends response in chunked encoding. is there a way to
>> get the chunked response size ?
> You can switch off transfer-encoding in libcurl, and then you get all the
> chunked data to deal with - but then you also have to do the entire chunked
> decoding yourself.
> --
> /
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Received on 2015-06-20