starting gateway

lib/Gateway.ts

@@ -0,0 +1,37 @@
+type AnyFunc = (...args: unknown) => unknown;
+type Gateway = (req: Request, res: Response, next: AnyFunc) => Promise<void>;
+
+interface GatewayOptions {
+  redirect_url: string;
+  use_stored_sessions?: boolean;
+}
+
+class GatewayClass {
+  private options: GatewayOptions;
+
+  public constructor (options: GatewayOptions) {
+    this.options = options;
+  }
+
+  private redirect (res): void {
+    res.statusCode = 302;
+    res.setHeader ('Location', this.options.redirect_url);
+    res.end ();
+  }
+
+  private async authenticate (req): Promise<boolean> {
+    return false;
+  }
+
+  public async process_request (req: Request, res: Response, next: AnyFunc): Promise<void> {
+    if (await this.authenticate (req))
+      next ();
+    else
+      this.redirect (res);
+  }
+}
+
+export default function create_gateway (options: GatewayOptions): Gateway {
+  const g = new GatewayClass (options);
+  return g.process_request;
+}