Downloading a file via curl in c++ from dropbox - c++

Question

I want to download a file from a dropbox shared link using curl in a c++ program
I found a dropbox api pdf that showed me how to do it
#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: %s\n",
curl_easy_strerror(res));
/* always cleanup */
curl_easy_cleanup(curl);
printf ("\nFinished curl test.\n");
}
curl_global_cleanup();
printf ("Done!\n");
return 0;
}
However, the comments supplied don't offer much explanation for me, and I can't get it to work.
I don't understand these three lines of code:
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\"}");
I think I have to replace some stuff but I don't know what

Answer 1

"I think I have to replace some stuff but I don't know what" : Replace <ACCESS_TOKEN> with your actual access token.
You should also set the "Content-Type:" header to an appropriate value for the data you are fetching.
You must also change the value of the "Dropbox-API-Arg" header to match the file you are trying to get.

Answer 2

I finally found the solution to my problem.
Turns out I didn't have to use the Dropbox API
Here is the code
#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;
}
Thanks you guys for trying to help me. I appreciate