OIDC: register (#11727)

* update uses of ValidatedDelegatedAuthConfig to broader OidcClientConfig type

* add OIDC register flow to registration page

* pass prompt param to auth url creation

* update type

* lint

* test registration oidc button

* fix: reference state inside setState

* comment

src/utils/oidc/authorize.ts

@@ -35,11 +35,14 @@ export const startOidcLogin = async (
     clientId: string,
     homeserverUrl: string,
     identityServerUrl?: string,
+    isRegistration?: boolean,
 ): Promise<void> => {
     const redirectUri = window.location.origin;
 
     const nonce = randomString(10);
 
+    const prompt = isRegistration ? "create" : undefined;
+
     const authorizationUrl = await generateOidcAuthorizationUrl({
         metadata: delegatedAuthConfig.metadata,
         redirectUri,
@@ -47,6 +50,7 @@ export const startOidcLogin = async (
         homeserverUrl,
         identityServerUrl,
         nonce,
+        prompt,
     });
 
     window.location.href = authorizationUrl;

src/utils/oidc/isUserRegistrationSupported.ts

@@ -0,0 +1,30 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { OidcClientConfig } from "matrix-js-sdk/src/matrix";
+
+/**
+ * Check the create prompt is supported by the OP, if so, we can do a registration flow
+ * https://openid.net/specs/openid-connect-prompt-create-1_0.html
+ * @param delegatedAuthConfig config as returned from discovery
+ * @returns whether user registration is supported
+ */
+export const isUserRegistrationSupported = (delegatedAuthConfig: OidcClientConfig): boolean => {
+    // The OidcMetadata type from oidc-client-ts does not include `prompt_values_supported`
+    // even though it is part of the OIDC spec, so cheat TS here to access it
+    const supportedPrompts = (delegatedAuthConfig.metadata as Record<string, unknown>)["prompt_values_supported"];
+    return Array.isArray(supportedPrompts) && supportedPrompts?.includes("create");
+};