使用libcurl 通过表单方式上传图片

最新推荐文章于 2024-09-26 15:11:36 发布

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最新推荐文章于 2024-09-26 15:11:36 发布

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分类专栏： linux 嵌入式文章标签： libcurl 图片表单

本文链接：https://blog.youkuaiyun.com/rougker/article/details/103480889

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本文介绍如何使用libcurl库进行HTTP POST请求，具体演示了如何上传文件和设置表单字段，同时展示了如何禁用期望头（Expect header），避免100-continue响应导致的阻塞。

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

#include <curl/curl.h>

int main(int argc, char *argv[])
{
  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);

  /* Fill in the file upload field */
  curl_formadd(&formpost,
               &lastptr,
               CURLFORM_COPYNAME, "image",
               CURLFORM_FILE, "/home/leolaw/girl.jpg",
               CURLFORM_END);

  /* Fill in the submit field too, even if this is rarely needed */
  curl_formadd(&formpost,
               &lastptr,
               CURLFORM_COPYNAME, "submit",
               CURLFORM_COPYCONTENTS, "send",
               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://10.108.219.139:8081/api/upload/image");
    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);

    /* 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(formpost);
    /* free slist */
    curl_slist_free_all (headerlist);
  }
  return 0;
}

切忌：不可设置POST，否则会阻塞失败。curl_easy_setopt(curl, CURLOPT_POST, 1);