Communicate with middleware in pages via errors

[OliverSpeir]

Option 1: Error details

// page.astro
---
import type { APIContext } from "astro";
import type { AuthUser } from "../users";
import { login_path } from "./login_path";

const protected_route = <T extends AuthUser["role"] = "premium">(
  {
    locals: { auth },
    url,
    redirect,
  }: Pick<APIContext, "locals" | "url" | "redirect">,
  roles: Array<T> = ["premium"] as Array<T>
) => {
  if (!roles.includes(auth.user.role as T)) {
    throw Object.assign(redirect(login_path(url), 302), {
      __internal: true,
    });
  }
  return {
    user: auth.user as Extract<AuthUser, { role: T }>,
  };
};

const { user } = protected_route(Astro)
---

// middleware.ts
  try {
    return await next();
  } catch (e) {
    if (e instanceof Response && "__internal" in e && e.__internal === true) {
      return e;
    }
    // report error
}

Option 1 Discord message

Option2: Custom error class

export class ErrorWithResponse {
  constructor(message: string, private readonly builder: () => Response | Promise<Response>) {
    super(message);
  }
  
  render() {
    return this.builder();
  }
}

Option 2 Discord message

Example usecase:

Handle auth at page level