feat: refactor auth middleware to handle required and optional cross service token scenarios (#612)

* wip: fix variable name

* wip: remove redundant middleware in auth

* fix: auth middleware refactor

* fix(auth): fetching user for key params

* fix(auth): specs

* fix(auth): registering session controller endpoints

packages/api-gateway/src/Controller/RequiredCrossServiceTokenMiddleware.ts

@@ -0,0 +1,57 @@
+import { TimerInterface } from '@standardnotes/time'
+import { NextFunction, Response } from 'express'
+import { inject, injectable } from 'inversify'
+import { Logger } from 'winston'
+
+import { TYPES } from '../Bootstrap/Types'
+import { CrossServiceTokenCacheInterface } from '../Service/Cache/CrossServiceTokenCacheInterface'
+import { ServiceProxyInterface } from '../Service/Http/ServiceProxyInterface'
+import { AuthMiddleware } from './AuthMiddleware'
+
+@injectable()
+export class RequiredCrossServiceTokenMiddleware extends AuthMiddleware {
+  constructor(
+    @inject(TYPES.ServiceProxy) serviceProxy: ServiceProxyInterface,
+    @inject(TYPES.AUTH_JWT_SECRET) jwtSecret: string,
+    @inject(TYPES.CROSS_SERVICE_TOKEN_CACHE_TTL) crossServiceTokenCacheTTL: number,
+    @inject(TYPES.CrossServiceTokenCache) crossServiceTokenCache: CrossServiceTokenCacheInterface,
+    @inject(TYPES.Timer) timer: TimerInterface,
+    @inject(TYPES.Logger) logger: Logger,
+  ) {
+    super(serviceProxy, jwtSecret, crossServiceTokenCacheTTL, crossServiceTokenCache, timer, logger)
+  }
+
+  protected override handleSessionValidationResponse(
+    authResponse: { status: number; data: unknown; headers: { contentType: string } },
+    response: Response,
+    _next: NextFunction,
+  ): boolean {
+    if (authResponse.status > 200) {
+      response.setHeader('content-type', authResponse.headers.contentType)
+      response.status(authResponse.status).send(authResponse.data)
+
+      return false
+    }
+
+    return true
+  }
+
+  protected override handleMissingAuthHeader(
+    authHeaderValue: string | undefined,
+    response: Response,
+    _next: NextFunction,
+  ): boolean {
+    if (!authHeaderValue) {
+      response.status(401).send({
+        error: {
+          tag: 'invalid-auth',
+          message: 'Invalid login credentials.',
+        },
+      })
+
+      return false
+    }
+
+    return true
+  }
+}