Add Source::KeyAndPattern and DIDMethods::generate

Allow passing an additional string to a DID method in the generate
function.

Implement generate on DIDMethods to allow generating a DID from a set of
DID methods given a DID method name and optional additional string,
separated by a colon (':').

The additional string may be a prefix or pattern for the DID's
method-specific ID, according to the DID method.

CHANGELOG.md

@@ -35,6 +35,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Support HTTP(S) requests in WASM and on Android.
 - Support relative DID URLs in DID documents.
 - Support [publicKeyBase58][] for Ed25519.
+- Added `DIDMethods::generate` function.
 
 ### Changed
 - Make `ResolutionResult` struct public.
@@ -56,6 +57,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Make `jws::sign_bytes` return bytes instead of string.
 - Allow multiple proofs and multiple verification methods in a DID document
 - Bundle `json-ld` crate, for `crates.io` release.
+- Added `Source::KeyAndPattern` enum variant.
 
 ### Fixed
 - Fix `tz1` hashing.

did-ethr/src/lib.rs

@@ -138,6 +138,13 @@ impl DIDMethod for DIDEthr {
     fn generate(&self, source: &Source) -> Option<String> {
         let jwk = match source {
             Source::Key(jwk) => jwk,
+            Source::KeyAndPattern(jwk, pattern) => {
+                if !pattern.is_empty() {
+                    // TODO: support pattern
+                    return None;
+                }
+                jwk
+            }
             _ => return None,
         };
         let hash = match ssi::keccak_hash::hash_public_key(jwk) {

did-key/src/lib.rs

@@ -193,6 +193,13 @@ impl DIDMethod for DIDKey {
     fn generate(&self, source: &Source) -> Option<String> {
         let jwk = match source {
             Source::Key(jwk) => jwk,
+            Source::KeyAndPattern(jwk, pattern) => {
+                if !pattern.is_empty() {
+                    // pattern not supported
+                    return None;
+                }
+                jwk
+            }
             _ => return None,
         };
         let did = match jwk.params {

did-sol/src/lib.rs

@@ -140,6 +140,13 @@ impl DIDMethod for DIDSol {
     fn generate(&self, source: &Source) -> Option<String> {
         let jwk = match source {
             Source::Key(jwk) => jwk,
+            Source::KeyAndPattern(jwk, pattern) => {
+                if !pattern.is_empty() {
+                    // pattern not supported
+                    return None;
+                }
+                jwk
+            }
             _ => return None,
         };
         let did = match jwk.params {

did-tezos/src/lib.rs

@@ -265,6 +265,13 @@ impl DIDMethod for DIDTz {
     fn generate(&self, source: &Source) -> Option<String> {
         let jwk = match source {
             Source::Key(jwk) => jwk,
+            Source::KeyAndPattern(jwk, pattern) => {
+                if !pattern.is_empty() {
+                    // TODO: support pattern
+                    return None;
+                }
+                jwk
+            }
             _ => return None,
         };
         let hash = match hash_public_key(jwk) {

src/did.rs

@@ -206,7 +206,10 @@ pub enum Resource {
 #[derive(Debug, Clone, PartialEq)]
 #[non_exhaustive]
 pub enum Source<'a> {
+    /// Public key
     Key(&'a JWK),
+    /// Public key and additional pattern
+    KeyAndPattern(&'a JWK, &'a str),
 }
 
 #[derive(Debug, Serialize, Deserialize, Clone, Default)]
@@ -292,6 +295,30 @@ impl<'a> DIDMethods<'a> {
         };
         Ok(method)
     }
+
+    /// Generate a DID given some input
+    pub fn generate(&self, source: &Source) -> Option<String> {
+        let (jwk, pattern) = match source {
+            Source::Key(_) => {
+                // Need name/pattern to select DID method
+                return None;
+            }
+            Source::KeyAndPattern(jwk, pattern) => (jwk, pattern),
+        };
+        let mut parts = pattern.splitn(2, ':');
+        let method_name = parts.next().unwrap();
+        let method = match self.methods.get(method_name) {
+            Some(method) => method,
+            None => return None,
+        };
+        if let Some(method_pattern) = parts.next() {
+            let source = Source::KeyAndPattern(jwk, method_pattern);
+            method.generate(&source)
+        } else {
+            let source = Source::Key(jwk);
+            method.generate(&source)
+        }
+    }
 }
 
 #[cfg_attr(target_arch = "wasm32", async_trait(?Send))]