On Tue, Dec 28, 2010 at 5:08 PM, Daniel Stenberg <daniel_at_haxx.se> wrote:

> On Tue, 28 Dec 2010, amit paliwal wrote:
>
> I want to pass additional custom data on top of HTTP GET to the HTTP
>> Server, which means I need to build HTTP GET message including the payload
>> and send it to HTTP Server by saying curl_easy_perform().
>>
>> Do I need to use CURLOPT_READFUNCTION option and maintain one callback
>> function where i can append my custom data? But then how will the library
>> call my custom payload and send it on top of HTTP GET.
>>
>
> Make the request out to be a POST, like use CURLOPT_POSTFIELDS or
> CURLOPT_READFUNCTION or whatever you think is the best way.
>
> Then you alter the method to a GET with CURLOPT_CUSTOMREQUEST and you
> should be good to go. You may want to remove/alter the "Content-Type:" that
> a mere POST will make libcurl use by default (use CURLOPT_HTTPHEADER for
> that).
>
> -- Reply: I tried the above step but it did not work. I received HTTP
> response message from server and my callback got called with the payload. In
> my callback I forced to send another GET message and tried the gET to take
> data from my read callback, but it did nto happen that way.
>

sample code goes like this:

size_t write_data( void *buffer, size_t size, size_t nmemb, void *userp )
{
  int segsize = size * nmemb;

  /*TODO: we can think of making it a thread specific attribute as it will
be required for
   * individual session*/
  CURL *ctx = (CURL*)userp;
  printf("\nCurl object address is:%p",ctx);
  CURLcode ret;

  /*Prepare HTTP GET message here to send the response of the received DAPro
Message*/
  /* We need to pass the easy handle as User data to the write callback
   */
  curl_easy_setopt( ctx , CURLOPT_READDATA ,ctx);

  /* Set DAPro Parser's static function as write callback.
   */
  curl_easy_setopt( ctx , CURLOPT_READFUNCTION , readcb );

  /* Set the Request message to be a HTTP GET method
   */
  curl_easy_setopt(ctx, CURLOPT_CUSTOMREQUEST, "GET") ;

  ret = curl_easy_perform(ctx);
  if(CURLE_OK != ret)
  {
      printf("Error: %s\n", strerror(ret));
  }

  /* Return the number of bytes received, indicating to curl that all is
okay */
  return segsize;
}

size_t readcb(void *ptr, size_t size, size_t nitems, void *stream)
{
    printf("\nEntered inside read callback");

}

When write_data is executed and I send HTTP GET, I expect it to go in
readcb() function to take my custom data, but it is not happening.

> / daniel.haxx.se
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Received on 2010-12-30