Function deref_did_url 

pub fn deref_did_url<'a>(
    url: &DidUrl,
    doc: &'a DidDocument,
) -> Option<DereferencedResource<'a>>

Dereference a DID URL against an already-resolved DID Document.

This is the “secondary” dereference step from W3C DID Core §7.2 — the document has already been resolved; this function extracts the specific resource identified by the URL’s fragment.

Rules

• No fragment → returns the full document.
• Fragment matches a verificationMethod[].id → returns that VM.
• Fragment matches a service[].id → returns that service.
• Fragment matches nothing → returns None.

Fragment comparison strips any leading # and is exact-string. Per DID Core, fragment comparison is case-sensitive.

Example

let url = DidUrl::parse("did:ndn:com:acme:alice#key-0").unwrap();
match deref_did_url(&url, doc) {
    Some(ndn_security::did::url::DereferencedResource::VerificationMethod(vm)) => {
        println!("Found key: {}", vm.id);
    }
    _ => {}
}