通过 c++ 中的 curl 从 Dropbox 下载文件

Question

我想在 c++ 程序中使用 curl 从保管箱共享链接下载文件

我找到了一个保管箱 api pdf，它向我展示了如何做到这一点

#include <stdio.h>
#include <curl/curl.h>
int main (int argc, char *argv[])
{
CURL *curl;
CURLcode res;
/* In windows, this will init the winsock stuff */
curl_global_init(CURL_GLOBAL_ALL);
/* get a curl handle */
curl = curl_easy_init();
if(curl) {
printf ("Running curl test.n");
struct curl_slist *headers=NULL; /* init to NULL is important */
headers = curl_slist_append(headers, "Authorization: Bearer 
<ACCESS_TOKEN>");
headers = curl_slist_append(headers, "Content-Type:");
headers = curl_slist_append(headers, "Dropbox-API-Arg: 
{"path":"/test.txt"}");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
curl_easy_setopt(curl, CURLOPT_URL,
"https://content.dropboxapi.com/2/files/download");
curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "");
/* 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: %sn",
curl_easy_strerror(res));
/* always cleanup */
curl_easy_cleanup(curl);
printf ("nFinished curl test.n");
}
curl_global_cleanup();
printf ("Done!n");
return 0;
}

但是，提供的评论并没有为我提供太多解释，我无法让它工作。

我不明白这三行代码：

headers = curl_slist_append(headers, "Authorization: Bearer <ACCESS_TOKEN>");
headers = curl_slist_append(headers, "Content-Type:");
headers = curl_slist_append(headers, "Dropbox-API-Arg:{"path":"/test.txt"}");

我想我必须更换一些东西，但我不知道是什么

Answer 1

"我想我必须替换一些东西，但我不知道是什么"：将<ACCESS_TOKEN>替换为实际的访问令牌。

您还应该将"内容类型："标头设置为要获取的数据的适当值。

您还必须更改"Dropbox-API-Arg"标头的值，以匹配您尝试获取的文件。

Answer 2

我终于找到了解决问题的方法。

事实证明，我不必使用 Dropbox API

这是代码

#include <iostream>
#include <curl/curl.h>
using namespace std;
size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream)
{
size_t written;
written = fwrite(ptr, size, nmemb, stream);
return written;
}
int main(int argc, char** argv) {
CURL *curl;
FILE *fp;
const char* destination = "D:\Desktop\test.exe";
fp = fopen(destination, "wb");
curl = curl_easy_init();
/* A long parameter set to 1 tells the library to follow any Location: header 
* that the server sends as part of an HTTP header in a 3xx response. The 
*Location: header can specify a relative or an absolute URL to follow.
*/
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L); 
curl_easy_setopt(curl, CURLOPT_URL, "https://www.dropbox.com/s/09nd26tdyto23yz/BankAccount.exe?dl=1"); // "dl=0"changed to "dl=1" to force download
// disabe the SSL peer certificate verification allowing the program to download the file from dropbox shared link
// in case it is not used it displays an error message stating "SSL peer certificate or SSH remote key was not OK"
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
CURLcode res;
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
fclose(fp);

if (res ==CURLE_OK)
cout << "OK";
else
cout << curl_easy_strerror(res);
return 0;
}

谢谢你们试图帮助我。我很感激