Client registration using a "store" interface

src/server/auth/clients.ts

@@ -0,0 +1,20 @@
+import { OAuthClientInformationFull } from "../../shared/auth.js";
+
+/**
+ * Stores information about registered OAuth clients for this server.
+ */
+export interface OAuthRegisteredClientsStore {
+  /**
+   * Returns information about a registered client, based on its ID.
+   */
+  getClient(clientId: string): OAuthClientInformationFull | undefined | Promise<OAuthClientInformationFull | undefined>;
+
+  /**
+   * Registers a new client with the server. The client ID and secret will be automatically generated by the library. A modified version of the client information can be returned to reflect specific values enforced by the server.
+   * 
+   * NOTE: Implements must ensure that client secrets, if present, are expired in accordance with the `client_secret_expires_at` field.
+   * 
+   * If unimplemented, dynamic client registration is unsupported.
+   */
+  registerClient?(client: OAuthClientInformationFull): OAuthClientInformationFull | Promise<OAuthClientInformationFull>;
+}

src/server/auth/handlers/clientRegistration.ts

@@ -2,46 +2,69 @@ import { Request, Response } from "express";
 import { OAuthClientInformationFull, OAuthClientMetadataSchema, OAuthClientRegistrationError } from "../../../shared/auth.js";
 import crypto from 'node:crypto';
 import bodyParser from 'body-parser';
+import { OAuthRegisteredClientsStore } from "../clients.js";
 
-async function handler(requestBody: unknown): Promise<OAuthClientInformationFull | OAuthClientRegistrationError> {
-  let clientMetadata;
-  try {
-    clientMetadata = OAuthClientMetadataSchema.parse(requestBody);
-  } catch (error) {
-    return { error: "invalid_client_metadata", error_description: String(error) };
+export type ClientRegistrationHandlerOptions = {
+  /**
+   * A store used to save information about dynamically registered OAuth clients.
+   */
+  store: OAuthRegisteredClientsStore;
+
+  /**
+   * The number of seconds after which to expire issued client secrets, or 0 to prevent expiration of client secrets (not recommended).
+   * 
+   * If not set, defaults to 30 days.
+   */
+  clientSecretExpirySeconds?: number;
+};
+
+const DEFAULT_CLIENT_SECRET_EXPIRY_SECONDS = 30 * 24 * 60 * 60; // 30 days
+
+export function clientRegistrationHandler({ store, clientSecretExpirySeconds = DEFAULT_CLIENT_SECRET_EXPIRY_SECONDS }: ClientRegistrationHandlerOptions) {
+  if (!store.registerClient) {
+    throw new Error("Client registration store does not support registering clients");
   }
 
-  // Implement RFC 7591 dynamic client registration
-  const clientId = crypto.randomUUID();
-  const clientSecret = clientMetadata.token_endpoint_auth_method !== 'none'
-    ? crypto.randomBytes(32).toString('hex')
-    : undefined;
-  const clientIdIssuedAt = Math.floor(Date.now() / 1000);
+  async function register(requestBody: unknown): Promise<OAuthClientInformationFull | OAuthClientRegistrationError> {
+    let clientMetadata;
+    try {
+      clientMetadata = OAuthClientMetadataSchema.parse(requestBody);
+    } catch (error) {
+      return { error: "invalid_client_metadata", error_description: String(error) };
+    }
 
-  const clientInfo: OAuthClientInformationFull = {
-    ...clientMetadata,
-    client_id: clientId,
-    client_secret: clientSecret,
-    client_id_issued_at: clientIdIssuedAt,
-    client_secret_expires_at: 0 // Set to 0 for non-expiring secret
-  };
+    // Implement RFC 7591 dynamic client registration
+    const clientId = crypto.randomUUID();
+    const clientSecret = clientMetadata.token_endpoint_auth_method !== 'none'
+      ? crypto.randomBytes(32).toString('hex')
+      : undefined;
+    const clientIdIssuedAt = Math.floor(Date.now() / 1000);
 
-  // TODO: Store client information securely
+    let clientInfo: OAuthClientInformationFull = {
+      ...clientMetadata,
+      client_id: clientId,
+      client_secret: clientSecret,
+      client_id_issued_at: clientIdIssuedAt,
+      client_secret_expires_at: clientSecretExpirySeconds > 0 ? clientIdIssuedAt + clientSecretExpirySeconds : 0
+    };
 
-  return clientInfo;
-}
-
-export const clientRegistrationHandler = (req: Request, res: Response) => bodyParser.json()(req, res, (err) => {
-  if (err === undefined) {
-    handler(req.body).then((result) => {
-      if ("error" in result) {
-        res.status(400).json(result);
-      } else {
-        res.status(201).json(result);
-      }
-    }, (error) => {
-      console.error("Uncaught error in client registration handler:", error);
-      res.status(500).end("Internal Server Error");
-    });
+    clientInfo = await store.registerClient!(clientInfo);
+    return clientInfo;
   }
-});
+
+  // Actual request handler
+  return (req: Request, res: Response) => bodyParser.json()(req, res, (err) => {
+    if (err === undefined) {
+      register(req.body).then((result) => {
+        if ("error" in result) {
+          res.status(400).json(result);
+        } else {
+          res.status(201).json(result);
+        }
+      }, (error) => {
+        console.error("Uncaught error in client registration handler:", error);
+        res.status(500).end("Internal Server Error");
+      });
+    }
+  });
+}

src/shared/auth.ts

@@ -76,7 +76,7 @@ export const OAuthClientMetadataSchema = z.object({
   jwks: z.any().optional(),
   software_id: z.string().optional(),
   software_version: z.string().optional(),
-}).passthrough();
+}).strip();
 
 /**
  * RFC 7591 OAuth 2.0 Dynamic Client Registration client information
@@ -86,7 +86,7 @@ export const OAuthClientInformationSchema = z.object({
   client_secret: z.string().optional(),
   client_id_issued_at: z.number().optional(),
   client_secret_expires_at: z.number().optional(),
-}).passthrough();
+}).strip();
 
 /**
  * RFC 7591 OAuth 2.0 Dynamic Client Registration full response (client information plus metadata)