using libcurl to call Amazon s3 RESTful service - c++

Question

I am writing a piece of c++ code with libcurl to call Amazon s3 RESTful service as follows:
void SampleOfS3Get()
{
//Init curl
curl_global_init(CURL_GLOBAL_ALL);
CURL* curlHandle = curl_easy_init();
//Init var
char* curlErrStr = (char*)malloc(CURL_ERROR_SIZE);
curl_slist* httpHeaders = NULL;
const char* date = getDateForHeader();
httpHeaders = curl_slist_append(httpHeaders, "Host: s3.amazonaws.com");//Set Host
httpHeaders = curl_slist_append(httpHeaders, date);//Set Date
httpHeaders = curl_slist_append(httpHeaders, getAuthorizationForHeader("AKIAISZALBSY-----XGQ","tIzCC----------/Jsn5KqTfuCAWyD1eyeOKStx0",date));//Set authorization
//Execute
if(curlHandle)
{
curl_easy_setopt(curlHandle, CURLOPT_VERBOSE, CURLOPT_STDERR);//Set verbose mode
curl_easy_setopt(curlHandle, CURLOPT_FOLLOWLOCATION,1);//Set automaticallly redirection
curl_easy_setopt(curlHandle, CURLOPT_MAXREDIRS,1);//Set max redirection times
curl_easy_setopt(curlHandle, CURLOPT_ERRORBUFFER, curlErrStr);//Set error buffer
curl_easy_setopt(curlHandle, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);//Set http version 1.1
curl_easy_setopt(curlHandle, CURLOPT_HEADER, httpHeaders);//Set headers
curl_easy_setopt(curlHandle, CURLOPT_URL, "http://s3.amazonaws.com/");//Set URL
CURLcode curlErr = curl_easy_perform(curlHandle);//Perform
if(curlErr)
{
cout<<curl_easy_strerror(curlErr)<<endl;
}
//Output redirection url
if(CURLE_OK == curlErr)
{
char *url;
curlErr = curl_easy_getinfo(curlHandle, CURLINFO_EFFECTIVE_URL, &url);
if((CURLE_OK == curlErr) && url)
cout<<"CURLINFO_EFFECTIVE_URL: "<<url<<endl;
}
/* Clean-up libcurl */
curl_global_cleanup();
}
}
This function calls the "GET SERVICE" to get the list of all buckets for a specified user.But the HTTP response of this HTTP request turns out to be "a temporary redirect to http://aws.amazon.com/s3" with http state code 307.
Then I find it in the official document which implies that caller should handle the redirection himself,so I add CURLOPT_FOLLOWLOCATION attribute as well.Then the result turns out to be a webpage content of amazon s3.
More details:http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html?r=1821
When I use the example accessID and accessKey in the above link,i get the right signature as "Example List All My Buckets" shows.It confused me that the server redirect my request instead of returning the expected all bucket list of my own(using my own accessID and accessKey).
Somebody encounter the similar problem like mine?SOS...

Answer 1

You should really start by reading http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAPI.html first, as your current code contains many issues. Especially make sure you fully understand how Signing and Authenticating REST Requests work.

Answer 2

This small C++ project seems to do cURL based File PUTs to AWS S3.
with CMake, one can generate VC++ Project/solutions and build it into .LIB static library, or, use it as source code, in your VC++ Solution.
I used it in a VC++ 2013 MFC Project.
Hope it helps.
https://github.com/cedricve/AWS-S3-Cpp-REST-API