C++使用curl下载文件（post请求）

使用curl经过post请求下载，代码如下：

#include<iostream>
#include<string>
#include<curl\curl.h>
using namespace std;

//下载文件数据接收函数
size_t dl_req_reply(void *buffer, size_t size, size_t nmemb, void *user_p)
{
	FILE *fp = (FILE *)user_p;
	size_t return_size = fwrite(buffer, size, nmemb, fp);
	//cout << (char *)buffer << endl;
	return return_size;
}

//http POST请求文件下载  
CURLcode dl_curl_post_req(const string &url, const string &postParams, string filename)
{
	//int len = filename.length();
	//char* file_name = new char(len + 1);//char*最后有一个结束字符\0
	//strcpy_s(file_name, len + 1, filename.c_str());
	//FILE *fp = fopen(file_name, "wb");

	const char* file_name = filename.c_str();
	char* pc = new char[1024];//足够长
	strcpy(pc, file_name);

	FILE *fp = fopen(pc, "wb");

	// curl初始化  
	CURL *curl = curl_easy_init();
	// curl返回值 
	CURLcode res;
	if (curl)
	{
		// set params
		//设置curl的请求头
		struct curl_slist* header_list = NULL;
		header_list = curl_slist_append(header_list, "User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko Core/1.63.6788.400 QQBrowser/10.3.2843.400");
		header_list = curl_slist_append(header_list, "Content-Type: application/x-www-form-urlencoded; charset=UTF-8");
		curl_easy_setopt(curl, CURLOPT_HTTPHEADER, header_list);

		//不接收响应头数据0代表不接收 1代表接收
		curl_easy_setopt(curl, CURLOPT_HEADER, 0);

		//设置请求为post请求
		curl_easy_setopt(curl, CURLOPT_POST, 1);


		//设置请求的URL地址
		curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
		//设置post请求的参数
		curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postParams.c_str());

		//设置ssl验证
		curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, false);
		curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, false);

		//CURLOPT_VERBOSE的值为1时，会显示详细的调试信息
		curl_easy_setopt(curl, CURLOPT_VERBOSE, 0);

		curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL);

		//设置数据接收和写入函数
		curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &dl_req_reply);
		curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);

		curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);

		//设置超时时间
		//curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 6);
		//curl_easy_setopt(curl, CURLOPT_TIMEOUT, 6);

		// 开启post请求
		res = curl_easy_perform(curl);
	}
	//释放curl 
	curl_easy_cleanup(curl);
	//释放文件资源
	fclose(fp);
	return res;
}
int main()
{
	string dl_url = "post请求下载文件地址";
	string postParams = "post请求下载参数";
	string filename = "文件存储名称";
	auto res3 = dl_curl_post_req(dl_url, "", filename);
	if (res3 == CURLE_OK)
	{
		cout << "下载成功！" << endl;
	}

	getchar();
	return 0;
}

将代码中的下载地址，请求参数和文件名替换成自己的，就可以直接下载了。