Creating libcurl http post form

Question

How do i create a curl_form e.g to do a post on stackoverflow?

If i look in source of question form page, I see

Nam         


        

Answer 1

From the libcurl sample: http://curl.haxx.se/libcurl/c/postit2.html

You don't manipulate curl_httppost directly. You'd write something like this to set the m-address field.

CURL *curl;
CURLcode res;

struct curl_httppost *formpost=NULL;
struct curl_httppost *lastptr=NULL;
struct curl_slist *headerlist=NULL;
static const char buf[] = "Expect:";

curl_global_init(CURL_GLOBAL_ALL);

curl_formadd(&formpost,
             &lastptr,
             CURLFORM_COPYNAME, "m-address",
             CURLFORM_COPYCONTENTS, "your@mail.com",
             CURLFORM_END);

curl = curl_easy_init();
headerlist = curl_slist_append(headerlist, buf);
if(curl) {
    /* what URL that receives this POST */ 
    curl_easy_setopt(curl, CURLOPT_URL, "http://stackoverflow.com/someurl");
    if ( (argc == 2) && (!strcmp(argv[1], "noexpectheader")) )
      /* only disable 100-continue header if explicitly requested */ 
      curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headerlist);
    curl_easy_setopt(curl, CURLOPT_HTTPPOST, formpost);
    res = curl_easy_perform(curl);

    /* always cleanup */ 
    curl_easy_cleanup(curl);

    /* then cleanup the formpost chain */ 
    curl_formfree(formpost);
    /* free slist */ 
    curl_slist_free_all (headerlist);

Answer 2

As this form isn't a multipart one, maybe you can simply use : http://curl.haxx.se/libcurl/c/http-post.html

CURL *curl;
CURLcode res;

/* In windows, this will init the winsock stuff */ 
curl_global_init(CURL_GLOBAL_ALL);

/* get a curl handle */ 
curl = curl_easy_init();
if(curl) {
  /* First set the URL that is about to receive our POST. This URL can
   just as well be a https:// URL if that is what should receive the
   data. */ 
  curl_easy_setopt(curl, CURLOPT_URL, "http://postit.example.com/moo.cgi");
  /* Now specify the POST data */ 
  curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "m-address=your@mail.com");

  /* Perform the request, res will get the return code */ 
  res = curl_easy_perform(curl);
  /* Check for errors */ 
  if(res != CURLE_OK)
    fprintf(stderr, "curl_easy_perform() failed: %s\n",
          curl_easy_strerror(res));

  /* always cleanup */ 
  curl_easy_cleanup(curl);
}
curl_global_cleanup();