feat: Support purpose claim

Author: joachimvh

packages/uma/config/credentials/verifiers/default.json

@@ -8,6 +8,13 @@
       "@type": "TypedVerifier",
       "metaType": "urn:solidlab:uma:claims:formats:meta",
       "verifiers": [
+        {
+          "TypedVerifier:_verifiers_key": "http://www.w3.org/ns/odrl/2/purpose",
+          "TypedVerifier:_verifiers_value": {
+            "@id": "urn:uma:default:KeyValueVerifier",
+            "@type": "KeyValueVerifier"
+          }
+        },
         {
           "TypedVerifier:_verifiers_key": "urn:solidlab:uma:claims:formats:webid",
           "TypedVerifier:_verifiers_value": {

packages/uma/src/credentials/verify/KeyValueVerifier.ts

@@ -0,0 +1,21 @@
+import { getLoggerFor } from '@solid/community-server';
+import { ClaimSet } from '../ClaimSet';
+import { Credential } from '../Credential';
+import { Verifier } from './Verifier';
+
+/**
+ * A verifier that assigns the credential token value as claims value, with the format being used as claims key.
+ */
+export class KeyValueVerifier implements Verifier {
+  protected readonly logger = getLoggerFor(this);
+
+  constructor() {
+    this.logger.warn("You are using an KeyValueVerifier. DO NOT USE THIS IN PRODUCTION !!!");
+  }
+
+  public async verify(credential: Credential): Promise<ClaimSet> {
+    return {
+      [credential.format]: credential.token
+    }
+  }
+}

packages/uma/src/credentials/verify/TypedVerifier.ts

@@ -23,9 +23,13 @@ export class TypedVerifier implements Verifier {
     // Recursively verify in case of a meta credential token
     if (credential.format === this.metaType) {
       const metaClaims = {};
-      for (const [ format, token ] of Object.entries(credential.token)) {
-        Object.assign(metaClaims, await this.verify({ format, token }));
+      const metaToken = JSON.parse(credential.token);
+      for (const [ format, token ] of Object.entries(metaToken)) {
+        Object.assign(metaClaims, await this.verify({ format, token: token as string }));
       }
+
+      this.logger.info(`Combined verified claims into ${JSON.stringify(metaClaims)}`);
+
       return metaClaims;
     }
 

packages/uma/src/index.ts

@@ -10,6 +10,7 @@ export * from './credentials/verify/TypedVerifier';
 export * from './credentials/verify/UnsecureVerifier';
 export * from './credentials/verify/SolidOidcVerifier';
 export * from './credentials/verify/JwtVerifier';
+export * from './credentials/verify/KeyValueVerifier';
 
 // Dialog
 export * from './dialog/Input';