使用curl库进行HTTP上传

//重写把数据读入上传数据流函数
size_t read_file(void* buff, size_t size, size_t nmemb, void* userp)
{
size_t sizes = fread(buff, size, nmemb, (FILE *)userp);
return sizes;
}

int HTTP_file::upload_file(const char* url, const char* file_name)
{
if ("" == url || "" == file_name)
{
std::cout << "url地址或文件名为空,操作失败!" << std::endl;
return -1;
}
CURLcode res;	//easy_handle定义的一些错误码

//初始化libcurl
res = curl_global_init(CURL_GLOBAL_ALL);
if (res != CURLE_OK)
{
std::cerr << "init libcurl failed." << std::endl;
return -1;
}

//获取要上传的文件指针
FILE* r_file = fopen(file_name, "rb");
if (0 == r_file)
{
std::cerr << "the file /" " << file_name << " /"that you will read is not exist" << std::endl;
return -1;
}

CURL* easy_handle;

easy_handle = curl_easy_init();
if (0 == easy_handle)
{
std::cout << "get a easy_handle handle fail!" << std::endl;
fclose(r_file);
curl_global_cleanup();
curl_easy_cleanup(easy_handle);
return -1;
}

// 获取文件大小
fseek(r_file, 0, 2);
int file_size = ftell(r_file);
rewind(r_file);

curl_easy_setopt(easy_handle, CURLOPT_URL, url);		//获取URL地址
curl_easy_setopt(easy_handle, CURLOPT_UPLOAD, TRUE);	//告诉easy_handle是做上传操作
curl_easy_setopt(easy_handle, CURLOPT_READFUNCTION, &read_file);	//调用重写的读文件流函数
curl_easy_setopt(easy_handle, CURLOPT_READDATA, r_file);	//往read_file()函数中传入用户自定义的数据类型
curl_easy_setopt(easy_handle, CURLOPT_INFILE, r_file);		//定位作为上传的输入文件
curl_easy_setopt(easy_handle, CURLOPT_INFILESIZE, file_size);	//上传的字节数

//执行设置好的操作
res = curl_easy_perform(easy_handle);

//获取HTTP错误码
int HTTP_flag = 0;
curl_easy_getinfo(easy_handle, CURLINFO_RESPONSE_CODE , &HTTP_flag);

//一般清理动作
fclose(r_file);
curl_global_cleanup();
curl_easy_cleanup(easy_handle);

std::cout << "操作本地文件:" << file_name << "; url:" << url << ".";
//检测HTTP错误码和执行操作结果
if ((0 != check_error(HTTP_flag)) || (CURLE_OK != res))
{
std::cout << "失败!" << std::endl;
return -1;
}
else
{
std::cout << "成功!" << std::endl;
return 0;
}
}