用libcurl库POST上传图片用二进制流方式_libcurl如何上传文件-优快云博客

本文详细介绍了如何使用libcurl库实现文件的上传功能。通过具体的C语言代码示例，展示了设置HTTP头部信息、读取文件、初始化CURL句柄、设置URL、POST请求等关键步骤。同时，还涉及了文件大小的获取、错误处理及资源释放等内容。

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官网API：https://curl.haxx.se/libcurl/c/curl_easy_setopt.html

仔细阅读API。

int upload_file(char *ilimagePath)
{
   bool res = false;
   int ret = 0;

   printf ("line:%d upload_file start\n", __LINE__);

   if (!imagePath)
   {
       printf("argument can't be empty\n");
       return false;
   }

   FILE * file = fopen(imagePath, "rb");
   if (file == NULL)
   {
       printf("%s open file failed\n", imagePath);
       return false;
   }

   /* get file size */
   struct stat fstat;
   ret = stat(imagePath, &fstat);
   if (ret != 0)
   {
       fclose(file);
       printf (" %s stat file failed\n", imagePath);
       return false;
   }

   long filesize = fstat.st_size;
   struct curl_slist *headers=NULL;

   CURL *curl;
   char url[1024] = {0};

   curl = curl_easy_init();
   if (curl)
   {
       sprintf(url, "http://192.168.110.119:10086/image?name=%s","test");
   #if 1
       //设定自定义头
       //前往官网查看CURLOPT_HTTPHEADER>>
       headers = curl_slist_append(headers, "Host: 192.168.110.119");
       headers = curl_slist_append(headers, "Content-Type: image/jpeg");
       headers = curl_slist_append(headers, "Connection: Keep-Alive");
       headers = curl_slist_append(headers, "Cache-Control: no-cache");

       //set headers
       curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
   #endif

       curl_easy_setopt(curl, CURLOPT_URL, url);

       curl_easy_setopt(curl, CURLOPT_WRITEDATA, NULL);
       curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);

       curl_easy_setopt(curl, CURLOPT_READDATA, file);
       curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);

       curl_easy_setopt(curl, CURLOPT_POST, 1L);               //POST

       curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);           //开启/关闭打印调试详细信息模式

/* 指定图片大小，否则遇到'\0'就停止了*/
curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, filesize);

       printf("start send file to server\n");

       CURLcode code = curl_easy_perform(curl);
       if (code == CURLE_OK)
       {
           res = true;
       }
       else
       {
           printf("line:%d curl_easy_perform() failed: %s\n", __LINE__, curl_easy_strerror(code));
       }

       curl_easy_cleanup(curl);
       curl_slist_free_all(headers);
   }

   fclose(file);

   return res;
}