backend-{plugin,app}-api: add HttpAuthService + initial implementation

Co-authored-by: Fredrik Adelöw <freben@gmail.com>
Co-authored-by: Carl-Erik Bergström <cbergstrom@spotify.com>
Co-authored-by: blam <ben@blam.sh>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/backend-plugin-api/src/services/definitions/HttpAuthService.ts

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2024 The Backstage Authors
+ *
+ * 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 { Request, Response, Handler } from 'express';
+import {
+  BackstageUserCredentials,
+  BackstageServiceCredentials,
+  BackstageCredentials,
+} from './AuthService';
+
+/** @public */
+export type BackstageUnauthorizedCredentials = {
+  $$type: '@backstage/BackstageCredentials';
+
+  type: 'unauthorized';
+};
+
+/** @public */
+export type BackstageCredentialTypes = {
+  user: BackstageUserCredentials;
+  'user-cookie': BackstageUserCredentials;
+  service: BackstageServiceCredentials;
+  unauthorized: BackstageUnauthorizedCredentials;
+};
+
+/** @public */
+export interface HttpAuthService {
+  createHttpPluginRouterMiddleware(): Handler;
+
+  credentials<TAllowed extends keyof BackstageCredentialTypes>(
+    req: Request,
+    options: {
+      allow: Array<TAllowed>;
+    },
+  ): Promise<BackstageCredentialTypes[TAllowed]>;
+
+  // TODO: Keep an eye on this, might not be needed
+  requestHeaders(options?: {
+    forward?: BackstageCredentials;
+  }): Promise<Record<string, string>>;
+
+  issueUserCookie(res: Response): Promise<void>;
+}

packages/backend-plugin-api/src/services/definitions/coreServices.ts

@@ -67,6 +67,15 @@ export namespace coreServices {
     import('./DiscoveryService').DiscoveryService
   >({ id: 'core.discovery' });
 
+  /**
+   * The service reference for the plugin scoped {@link HttpAuthService}.
+   *
+   * @public
+   */
+  export const httpAuth = createServiceRef<
+    import('./HttpAuthService').HttpAuthService
+  >({ id: 'core.httpAuth' });
+
   /**
    * The service reference for the plugin scoped {@link HttpRouterService}.
    *

packages/backend-plugin-api/src/services/definitions/index.ts

@@ -30,6 +30,11 @@ export type { RootConfigService } from './RootConfigService';
 export type { DatabaseService } from './DatabaseService';
 export type { DiscoveryService } from './DiscoveryService';
 export type { HttpRouterService } from './HttpRouterService';
+export type {
+  HttpAuthService,
+  BackstageCredentialTypes,
+  BackstageUnauthorizedCredentials,
+} from './HttpAuthService';
 export type {
   LifecycleService,
   LifecycleServiceStartupHook,