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lib/Amazon/PAApi5/Signature.pm  view on Meta::CPAN

}

sub _prepare_canonical_url {
    my ($self) = @_;

    my $canonical_url = $self->http_method . "\n";

    $canonical_url .= $self->resource_path . "\n\n";

    my $signed_headers = '';
    for my $key (grep { $_ !~ m!content-type! } sort keys %{$self->aws_headers}) {
        $signed_headers .=  lc($key) . ';';
        $canonical_url .= lc($key) . ':' . $self->aws_headers->{$key} . "\n";
    }

    $canonical_url .= "\n";

    $self->str_signed_header(substr($signed_headers, 0, -1)); # remove ';'
    $canonical_url .= $self->str_signed_header . "\n";

    $canonical_url .= sha256_hex($self->payload);

    return $canonical_url;
}

sub _prepare_string_to_sign {
    my ($self, $canonical_url) = @_;

    return join("\n",
        $self->hmac_algorithm,
        $self->x_amz_date,
        join('/', $self->current_date, $self->region, $self->service, $self->aws4_request),
        sha256_hex($canonical_url),
    );
}

sub _calculate_signature {
    my ($self, $string_to_sign) = @_;

    my $signature_key = $self->_get_signature_key;

    return lc(hmac_sha256_hex($string_to_sign, $signature_key));
}

sub _build_authorization_string {
    my ($self, $signature) = @_;

    return $self->hmac_algorithm . ' '
        . 'Credential=' . join('/', $self->access_key, $self->_get_date, $self->region, $self->service, $self->aws4_request)
        . ',SignedHeaders=' . $self->str_signed_header
        . ',Signature=' . $signature
    ;
}

sub headers {
    my ($self) = @_;

    my $aws_headers = $self->aws_headers;

    $aws_headers->{'content-encoding'} = 'amz-1.0';
    $aws_headers->{'content-type'}     = 'application/json; charset=UTF-8';
    $aws_headers->{'host'}             = $self->host;
    $aws_headers->{'x-amz-date'}       = $self->x_amz_date;
    $aws_headers->{'x-amz-target'}     = $self->_build_amz_target;

    my $canonical_url = $self->_prepare_canonical_url;

    my $string_to_sign = $self->_prepare_string_to_sign($canonical_url);

    my $signature = $self->_calculate_signature($string_to_sign);

    $aws_headers->{Authorization} = $self->_build_authorization_string($signature);

    $self->aws_headers($aws_headers);

    return %{$aws_headers};
}

sub headers_as_arrayref {
    return [shift->headers];
}

sub headers_as_hashref {
    return {shift->headers};
}

sub _get_signature_key {
    my ($self) = @_;

    my $k_date    = hmac_sha256($self->current_date, 'AWS4' . $self->secret_key);
    my $k_region  = hmac_sha256($self->region, $k_date);
    my $k_service = hmac_sha256($self->service, $k_region);
    my $k_signing = hmac_sha256($self->aws4_request, $k_service);

    return $k_signing;
}

sub _build_amz_target {
    return 'com.amazon.paapi5.v1.ProductAdvertisingAPIv1.' . shift->operation;
}

sub _get_time_stamp {
    return strftime("%Y%m%dT%H%M%SZ", gmtime()); # 20191128T235650Z
}

sub _get_date {
    return strftime("%Y%m%d", gmtime()); # 20191128
}

sub to_request {
    my ($self) = @_;

    return {
        method  => $self->http_method,
        uri     => $self->req_url,
        headers => $self->headers_as_hashref,
        content => $self->payload,
    };
}

1;