feat: JwksHandler

src/index.ts

@@ -374,6 +374,7 @@ export * from './server/description/StorageLocationStrategy';
 export * from './server/middleware/AcpHeaderHandler';
 export * from './server/middleware/CorsHandler';
 export * from './server/middleware/HeaderHandler';
+export * from './server/middleware/JwksHandler';
 export * from './server/middleware/StaticAssetHandler';
 export * from './server/middleware/WebSocketAdvertiser';
 

src/server/middleware/JwksHandler.ts

@@ -0,0 +1,42 @@
+import { HttpHandler, type HttpHandlerInput } from '../HttpHandler';
+import type { JwkGenerator } from '../../identity/configuration/JwkGenerator';
+import { MethodNotAllowedHttpError } from '../../util/errors/MethodNotAllowedHttpError';
+import { NotImplementedHttpError } from '../../util/errors/NotImplementedHttpError';
+
+export class JwksHandler extends HttpHandler {
+  public constructor(
+    private readonly path: string,
+    private readonly generator: JwkGenerator,
+  ) {
+    super();
+  }
+
+  public async canHandle({ request }: HttpHandlerInput): Promise<void> {
+    const { method, url } = request;
+
+    if (![ 'GET', 'HEAD' ].includes(method ?? '')) {
+      throw new MethodNotAllowedHttpError(
+        method ? [ method ] : undefined,
+        `Only GET or HEAD requests can target the storage description.`,
+      );
+    }
+
+    if (url !== this.path) {
+      throw new NotImplementedHttpError(`This handler is not configured for ${url}`);
+    }
+  }
+
+  public async handle({ request, response }: HttpHandlerInput): Promise<void> {
+    const key = await this.generator.getPublicKey();
+
+    // eslint-disable-next-line ts/naming-convention -- HTTP header
+    response.writeHead(200, { 'content-type': 'application/json' });
+
+    if (request.method === 'HEAD') {
+      response.end();
+      return;
+    }
+
+    response.end(JSON.stringify({ keys: [ Object.assign(key, { kid: 'TODO' }) ]}));
+  }
+}