fn canonicalize_headers()

in src/aws/credential.rs [410:451]

• 36 lines of code
• 7 McCabe index (conditional complexity)

fn canonicalize_headers(header_map: &HeaderMap) -> (String, String) {
    let mut headers = BTreeMap::<&str, Vec<&str>>::new();
    let mut value_count = 0;
    let mut value_bytes = 0;
    let mut key_bytes = 0;

    for (key, value) in header_map {
        let key = key.as_str();
        if ["authorization", "content-length", "user-agent"].contains(&key) {
            continue;
        }

        let value = std::str::from_utf8(value.as_bytes()).unwrap();
        key_bytes += key.len();
        value_bytes += value.len();
        value_count += 1;
        headers.entry(key).or_default().push(value);
    }

    let mut signed_headers = String::with_capacity(key_bytes + headers.len());
    let mut canonical_headers =
        String::with_capacity(key_bytes + value_bytes + headers.len() + value_count);

    for (header_idx, (name, values)) in headers.into_iter().enumerate() {
        if header_idx != 0 {
            signed_headers.push(';');
        }

        signed_headers.push_str(name);
        canonical_headers.push_str(name);
        canonical_headers.push(':');
        for (value_idx, value) in values.into_iter().enumerate() {
            if value_idx != 0 {
                canonical_headers.push(',');
            }
            canonical_headers.push_str(value.trim());
        }
        canonical_headers.push('\n');
    }

    (signed_headers, canonical_headers)
}