allow immediate redirect on auth

lib/AuthHandler.ts

@@ -13,6 +13,7 @@ interface AccessSettings {
   access_token_expires_in: number
   include_refresh_token?: boolean
   refresh_token_expires_in?: number
+  redirect_to?: string
   data?: Record<string, unknown>
 }
 
@@ -62,19 +63,21 @@ class AuthRequest {
     this._cookie_name = cookie;
   }
 
-  private default_header () {
+  private default_header (set_content = true) {
     this.response.setHeader ('Cache-Control', 'no-store');
     this.response.setHeader ('Pragma', 'no-cache');
-    this.response.setHeader ('Content-Type', 'application/json');
+    if (set_content)
+      this.response.setHeader ('Content-Type', 'application/json');
   }
 
   public async allow_access ({
     access_token_expires_in,
     include_refresh_token,
     refresh_token_expires_in,
+    redirect_to,
     data
   }: AccessSettings): Promise<AccessResult> {
-    this.default_header ();
+    this.default_header (typeof redirect_to !== 'string');
 
     const at = await auth.sign (
       'access_token',
@@ -109,6 +112,14 @@ class AuthRequest {
       res.refresh_expires_in = refresh_token_expires_in;
       result.refresh_token_id = rt.id;
     }
+
+    if (typeof redirect_to === 'string') {
+      this.response.setHeader ('Location', redirect_to);
+      this.response.writeHead (302);
+      this.response.end ();
+      return result;
+    }
+
     this.response.writeHead (200);
     this.response.end (JSON.stringify (res));
 
@@ -156,7 +167,7 @@ class AuthRequest {
   }
 }
 
-type AuthRequestHandler = (req: AuthRequest) => void|Promise<void>;
+type AuthRequestHandler = (req: AuthRequest) => Promise<void> | void;
 
 interface CreateHandlerOptions {
   refresh?: AccessSettings;