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.TH CURLOPT_AWS_SIGV4 3 "03 Jun 2020" libcurl libcurl
.SH NAME
CURLOPT_AWS_SIGV4 \- V4 signature
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_AWS_SIGV4, char *param);
.fi
.SH DESCRIPTION
Provides AWS V4 signature authentication on HTTP(S) header.
.PP
Pass a char * that is the collection of specific arguments are used for
creating outgoing authentication headers.  The format of the \fIparam\fP
option is:
.IP provider1[:provider2[:region[:service]]]
.IP provider1,\ provider2
The providers arguments are used for generating some authentication parameters
such as "Algorithm", "date", "request type" and "signed headers".
.IP region
The argument is a geographic area of a resources collection.
It is extracted from the host name specified in the URL if omitted.
.IP service
The argument is a function provided by a cloud.
It is extracted from the host name specified in the URL if omitted.
.PP
NOTE: This call set \fICURLOPT_HTTPAUTH(3)\fP to CURLAUTH_AWS_SIGV4.
Calling \fICURLOPT_HTTPAUTH(3)\fP with CURLAUTH_AWS_SIGV4 is the same
as calling this with \fB"aws:amz"\fP in parameter.
.PP
Example with "Test:Try", when curl uses the algorithm, it generates
\fB"TEST-HMAC-SHA256"\fP for "Algorithm", \fB"x-try-date"\fP and
\fB"X-Try-Date"\fP for "date", \fB"test4_request"\fP for "request type",
\fB"SignedHeaders=content-type;host;x-try-date"\fP for "signed headers"
.PP
If you use just "test", instead of "test:try", test is used for every
generated string.
.SH DEFAULT
By default, the value of this parameter is NULL.
Calling \fICURLOPT_HTTPAUTH(3)\fP with CURLAUTH_AWS_SIGV4 is the same
as calling this with \fB"aws:amz"\fP in parameter.
.SH PROTOCOLS
HTTP
.SH EXAMPLE
.nf
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);
  }
}
.fi
.SH AVAILABILITY
Added in 7.75.0
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH NOTES
This option overrides the other auth types you might have set in
\fICURLOPT_HTTPAUTH(3)\fP which should be highlighted as this makes this auth
method special.  This method cannot be combined with other auth types.
.PP
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
\fICURLOPT_POSTFIELDS(3)\fP.  Otherwise, it's the checksum of an empty buffer.
For requests like PUT, you can provide your own checksum in an HTTP header named
\fBx-provider2-content-sha256\fP.
.PP
For \fBaws:s3\fP, a \fBx-amz-content-sha256\fP header is added to every request
if not already present. For s3 requests with unknown payload, this header takes
the special value "UNSIGNED-PAYLOAD".
.SH "SEE ALSO"
.BR CURLOPT_HEADEROPT (3),
.BR CURLOPT_HTTPAUTH (3),
.BR CURLOPT_HTTPHEADER (3),
.BR CURLOPT_PROXYAUTH (3)