fn string_to_sign()

in src/aws/credential.rs [296:336]

• 33 lines of code
• 1 McCabe index (conditional complexity)

    fn string_to_sign(
        &self,
        date: DateTime<Utc>,
        scope: &str,
        request_method: &Method,
        url: &Url,
        canonical_headers: &str,
        signed_headers: &str,
        digest: &str,
    ) -> String {
        // Each path segment must be URI-encoded twice (except for Amazon S3 which only gets
        // URI-encoded once).
        // see https://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
        let canonical_uri = match self.service {
            "s3" => url.path().to_string(),
            _ => utf8_percent_encode(url.path(), &STRICT_PATH_ENCODE_SET).to_string(),
        };

        let canonical_query = canonicalize_query(url);

        // https://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
        let canonical_request = format!(
            "{}\n{}\n{}\n{}\n{}\n{}",
            request_method.as_str(),
            canonical_uri,
            canonical_query,
            canonical_headers,
            signed_headers,
            digest
        );

        let hashed_canonical_request = hex_digest(canonical_request.as_bytes());

        format!(
            "{}\n{}\n{}\n{}",
            ALGORITHM,
            date.format("%Y%m%dT%H%M%SZ"),
            scope,
            hashed_canonical_request
        )
    }