使用libcurl发送post请求

C语言代码如下：

#include <stdio.h>
#include <string.h>

#include <curl/curl.h>

int main(int argc, char *argv[])
{
  CURL *curl;
  CURLcode res;

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

  curl_global_init(CURL_GLOBAL_ALL);

    curl_formadd(&post,
                 &last,
                 CURLFORM_COPYNAME, "Msg_ID",
                 CURLFORM_COPYCONTENTS, "1423638030.127737481@websense.com", CURLFORM_END);

    curl_formadd(&post, 
                 &last, 
                 CURLFORM_COPYNAME, "Url",
                 CURLFORM_COPYCONTENTS, "http://www.aaa.com\nhttp://www.bbb.com", CURLFORM_END);

    curl_formadd(&post, 
                 &last, 
                 CURLFORM_COPYNAME, "File",
                 CURLFORM_FILE, "attachment_1",
                 CURLFORM_FILE, "attachment_2", CURLFORM_END);


  curl = curl_easy_init();
  /* initalize custom header list (stating that Expect: 100-continue is not
     wanted */
  headerlist = curl_slist_append(headerlist, buf);
  if(curl) {
    /* what URL that receives this POST */
    curl_easy_setopt(curl, CURLOPT_URL, "http://10.236.5.128/cgi-bin/backup");
    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, post);

    /* 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);

    /* then cleanup the formpost chain */
    curl_formfree(post);
    /* free slist */
    curl_slist_free_all (headerlist);
  }
  return 0;
}

POST /cgi-bin/backup HTTP/1.1
Host: 10.236.5.128
Accept: */*
Content-Length: 875
Expect: 100-continue
Content-Type: multipart/form-data; boundary=----------------------------8ca239ff87fe

HTTP/1.1 100 Continue

------------------------------8ca239ff87fe
Content-Disposition: form-data; name="Msg_ID"

1423638030.127737481@websense.com
------------------------------8ca239ff87fe
Content-Disposition: form-data; name="Url"

http://www.aaa.com
http://www.bbb.com
------------------------------8ca239ff87fe
Content-Disposition: form-data; name="File"
Content-Type: multipart/mixed, boundary=----------------------------81da9bb1e39e

------------------------------81da9bb1e39e
Content-Disposition: attachment; filename="attachment_1"
Content-Type: application/octet-stream

hello 
I'm the first attachment

------------------------------81da9bb1e39e
Content-Disposition: attachment; filename="attachment_2"
Content-Type: application/octet-stream

hi
I'm the second attachment

------------------------------81da9bb1e39e--
------------------------------8ca239ff87fe--
HTTP/1.1 200 OK
Date: Thu, 12 Feb 2015 09:36:06 GMT
Server: Apache/2.2.15 (CentOS)
Content-Length: 0
Connection: close
Content-Type: text/plain; charset=UTF-8