Creating a shared link for a Dropbox file using curl & C++ - c++

Question

I want to create a shared link for a dropbox file using curl & C++ on a windows 10 desktop.
I've already manage to upload the file to a dropbox folder using curl & C++.
When I try to create the link with command line it works with
curl -X POST https://api.dropboxapi.com/2/sharing/create_shared_link_with_settings --header "Authorization: Bearer <TOKEN>" --header "Content-Type: application/json" --data "{\"path\":\"path_of_the_file\"}"
but when I use this code to do the same in C++ it hangs at < HTTP/1.1 100 Continue
Here is my code :
CURL *curl;
CURLcode res;
curl = curl_easy_init();
if (curl) {
string readBuffer;
printf("Running curl test get shared link.\n");
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, FALSE); //no ssl
struct curl_slist *headers = NULL; // init to NULL is important
headers = curl_slist_append(headers, "Authorization: Bearer <TOKEN>");
headers = curl_slist_append(headers, "Content-Type: ");
headers = curl_slist_append(headers, "Dropbox-API-Arg: {\"path\":\"path_of_file\"}");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
curl_easy_setopt(curl, CURLOPT_POST, true);
curl_easy_setopt(curl, CURLOPT_VERBOSE, true);
curl_easy_setopt(curl, CURLOPT_URL, "https://api.dropboxapi.com/2/sharing/create_shared_link_with_settings");
// 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);
cout << readBuffer << endl;
printf("\nFinished curl test.\n");
}
curl_global_cleanup();
printf("Done get shared link!\n");
I've tried with content-type : application/json and adding fields but I can't reproduce what I'm doing with the command line

Answer 1

There are errors in the code, causing undefined behaviour.
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_easy_setopt(curl, CURLOPT_POST, true);
curl_easy_setopt(curl, CURLOPT_VERBOSE, true);
cUrl has a C API, C does not have overloads. Thus curl_easy_setopt is a multi-arg function, and the third argument type depends on the second argument value. CURLOPT_SSL_VERIFYPEER and CURLOPT_VERBOSE require long values, you pass the values as int. The size of the third argument is important exactly like this is in *printf functions. The proper calls must be
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
curl_easy_setopt(curl, CURLOPT_POST, 1L);
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
The second. 100 Continue means you have not passed the data for the POST request. The server received request and waits for further data. See
libcurl example - http-post.c.
I can't reproduce what I'm doing with the command line
Add the --libcurl to the command line for getting a C code performing the same actions as in the command line.

Answer 2

Thank you S.M. Here is the code that works
CURL *curl;
CURLcode res;
curl = curl_easy_init();
if (curl) {
string readBuffer;
printf("Running curl test get shared link.\n");
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L); //no ssl
struct curl_slist *headers = NULL; // init to NULL is important
headers = curl_slist_append(headers, "Authorization: Bearer <TOKEN>");
headers = curl_slist_append(headers, "Content-Type: application/json");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
curl_easy_setopt(curl, CURLOPT_POST, 1L);
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "{\"path\":\"path_to_the_file"}");
curl_easy_setopt(curl, CURLOPT_URL, "https://api.dropboxapi.com/2/sharing/create_shared_link_with_settings");
// 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);
cout << readBuffer << endl;
printf("\nFinished curl test.\n");
}
curl_global_cleanup();
printf("Done get shared link!\n");