CURLOPT_AWS_SIGV4(3)

NAME
CURLOPT_AWS_SIGV4 - V4 signature

SYNOPSIS
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_AWS_SIGV4, char *param);

DESCRIPTION
Provides AWS V4 signature authentication on HTTP(S) header.

Pass a char pointer that is the collection of specific arguments are used for creating outgoing authentication headers. The format of the param option is:

provider1[:provider2[:region[:service]]]

provider1, provider2
    The providers arguments are used for generating some authentication parameters such as "Algorithm", "date", "request type" and "signed headers".

region
    The argument is a geographic area of a resources collection. It is extracted from the hostname specified in the URL if omitted.

service
    The argument is a function provided by a cloud. It is extracted from the hostname specified in the URL if omitted.

NOTE: This call set CURLOPT_HTTPAUTH(3) to CURLAUTH_AWS_SIGV4. Calling CURLOPT_HTTPAUTH(3) with CURLAUTH_AWS_SIGV4 is the same as calling this with "aws:amz" in parameter.

Example with "Test:Try", when curl uses the algorithm, it generates "TEST-HMAC-SHA256" for "Algorithm", "x-try-date" and "X-Try-Date" for "date", "test4_request" for "request type", "SignedHeaders=content-type;host;x-try-date" for "signed headers"

If you use just "test", instead of "test:try", test is used for every generated string.

Setting CURLOPT_HTTPAUTH(3) with the CURLAUTH_AWS_SIGV4 bit set is the same as setting this option with a "aws:amz" parameter.

The application does not have to keep the string around after setting this option.

Using this option multiple times makes the last set string override the previous ones. Set it to NULL to disable its use again.

DEFAULT
NULL

PROTOCOLS
This functionality affects http only

EXAMPLE
int main(void)
{
  CURL *curl = curl_easy_init();

  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL,
                    "https://service.region.example.com/uri");
    curl_easy_setopt(curl, CURLOPT_AWS_SIGV4, "provider1:provider2");

    /* service and region can also be set in CURLOPT_AWS_SIGV4 */
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/uri");
    curl_easy_setopt(curl, CURLOPT_AWS_SIGV4,
                     "provider1:provider2:region:service");

    curl_easy_setopt(curl, CURLOPT_USERPWD, "MY_ACCESS_KEY:MY_SECRET_KEY");
    curl_easy_perform(curl);
  }
}

NOTES
This option overrides the other auth types you might have set in CURLOPT_HTTPAUTH(3) which should be highlighted as this makes this auth method special. This method cannot be combined with other auth types.

A sha256 checksum of the request payload is used as input to the signature calculation. For POST requests, this is a checksum of the provided CURLOPT_POSTFIELDS(3). Otherwise, it is the checksum of an empty buffer. For requests like PUT, you can provide your own checksum in an HTTP header named x-provider2-content-sha256.

For aws:s3, a x-amz-content-sha256 header is added to every request if not already present. For s3 requests with unknown payload, this header takes the special value "UNSIGNED-PAYLOAD".

AVAILABILITY
Added in curl 7.75.0

RETURN VALUE
curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).

SEE ALSO
CURLOPT_HEADEROPT(3), CURLOPT_HTTPAUTH(3), CURLOPT_HTTPHEADER(3), CURLOPT_PROXYAUTH(3)