curl/docs/libcurl/opts/CURLOPT_AWS_SIGV4.md

---

c: Copyright (C) Daniel Stenberg, daniel@haxx.se, et al. SPDX-License-Identifier: curl Title: CURLOPT_AWS_SIGV4 Section: 3 Source: libcurl See-also:

• CURLOPT_HEADEROPT (3)
• CURLOPT_HTTPAUTH (3)
• CURLOPT_HTTPHEADER (3)
• CURLOPT_PROXYAUTH (3) Protocol:
• HTTP Added-in: 7.75.0 ---

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.

DEFAULT

NULL

%PROTOCOLS%

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%

RETURN VALUE

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.