Hi, Oscar,

On Thu, Jul 12, 2012 at 10:33 PM, Oscar Koeroo <okoeroo_at_nikhef.nl> wrote:
> Hi Igor,
>
> Your approach breaks the fact that POST is typically a form-post. I recently
> had a problem with that breakage when I tried to POST data in JSON as raw
> data. libcurl can do this, but consider the incompatibility with something
> like Django.

The server code is written in ASP.
The code has a form behind.

The approach for the ASP code is as follows:
1. Send the boundary string.
2. Now post some arbitrary data about the file we are posting (like
the name and id).
3. Tell server we are posting the file in the image/bitmap format.
4. Send the file by chunks
5. Send the same boundary string again to indicate the transfer is done.

I didn't write the server code and I see only VB client code that I
need to translate.
Now in VB steps 2 and 3 are done in one write() call.

It is a multiform POST as the file is read and send out by chunks.
And so I have to follow a protocol to communicate with the server.

Any help on libcurl implementation?

It looks like I can upload the file with libcurl using the read
function approach, but
then I need to post it somehow.

I guess I need to look at the asp code in order to upload and post, right?

Thank you.

>
> Here's an example in C:
>
> [code]
> static size_t
> _curl_memread (void *ptr, size_t size, size_t nmemb, void *userp) {
> size_t read_size = 0;
> if (!userp) {
> return 0;
> }
> read_size = evbuffer_copyout((struct evbuffer *)userp, ptr, size * nmemb);
> return read_size;
> }
>
> /* POST */
> curl_easy_setopt(curl_handle, CURLOPT_POSTFIELDS,
> (char *)evpull(hc->out));
> curl_easy_setopt(curl_handle, CURLOPT_POSTFIELDSIZE,
> (long)evbuffer_get_length(hc->out));
> curl_easy_setopt(curl_handle, CURLOPT_URL, hc->url_query);
> curl_easy_setopt(curl_handle, CURLOPT_READFUNCTION, _curl_memread);
> curl_easy_setopt(curl_handle, CURLOPT_READDATA, (void *)hc->out);
>
> curl_easy_perform(curl_handle);
> [/code]
>
>
> cheers,
>
> Oscar
>
>
>
> On 13-07-12 07:01, Igor Korot wrote:
>> Guenter,
>>
>> On Thu, Jul 12, 2012 at 7:41 PM, Guenter <lists_at_gknw.net> wrote:
>>> Hi Igor,
>>> Am 13.07.2012 01:49, schrieb Igor Korot:
>>>
>>>> I'm transferring the code from VB to C/C++ to make it cross-platform.
>>>> In VB, there is following code:
>>>>
>>>> [code]
>>>> Dim boundary As String = "---------------------------"&
>>>> DateTime.Now.Ticks.ToString("x")
>>>> Dim newLine As String = System.Environment.NewLine
>>>> Dim boundaryBytes As Byte() =
>>>> System.Text.Encoding.ASCII.GetBytes(newLine& "--"& boundary&
>>>> newLine)
>>>> Dim request As Net.HttpWebRequest = Net.WebRequest.Create(uri)
>>>>
>>>> request.ContentType = "multipart/form-data; boundary="& boundary
>>>> request.Method = "POST"
>>>> request.KeepAlive = True
>>>> request.Credentials = Net.CredentialCache.DefaultCredentials
>>>>
>>>> Using requestStream As IO.Stream = request.GetRequestStream()
>>>> requestStream.Write(boundaryBytes, 0, boundaryBytes.Length)
>>>> End Using
>>>> [/code]
>>>>
>>>> AFAIU, it just simply writes boundary bytes to the socket as an ASCII
>>>> bytes sequence.
>>>> There is post-ing involved, no form submittal
>>>> Is it possible to do the same with libcurl?
>>>
>>> although this might be possible with libcurl - if I were you I would use
>>> Perl for this task; you have then a simple script which runs on almost every
>>> platform, no hassle with IDEs, compilers and MS dotnet redistributables
>>> install which you most likely need if you compile with MSVC 2010, and
>>> finally easy to write with your favourite text editor ...
>>
>> If it was that easy... ;-)
>> The program has GUI and it should be cross-platform, therefore I chose
>> wxWidgets/C++.
>> And I need the file to be transferred in addition to this simple
>> string for processing
>> and get the result of this processing back.
>>
>> Thank you.
>>
>>>
>>> libcurl is more meant for high-level tasks which you dont want ...
>>>
>>> Gün.
>>>
>>>
>>>
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>
>
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Received on 2012-07-13