First start to define what a self-healing URL is, a self-healing URL is like [medium. com](https://giorgiosaud.medium.com) posts a URL that has a unique identifier to allow redirect to a beauty URL path the structure of the URL normally is `https://giorgiosaud.medium.com/arquitectura-de-micro-frontend-trabaja-inteligentemente-no-m%C3%A1s-duro-8995417d821a` this structure is the ${baseUrl}/${post-name}-${id} this is the one which allows us to detect a malformed URL, if this is in the name will be replaced with the original one for example `https://giorgiosaud.medium.com/anything-8995417d821a` will redirect you to the self-healed original URL,

In other frameworks, it is easy to find information about it but in Astro, I can't find any doc related to it I made my implementation in which I use a self-healing ID in the content post, manually generated and I will add this ID to all my shareable links, and I made the implementation o a new [redirect] page inside /notebook path in pages folder:

```astro
---
import Container from "@components/container.astro";
import Layout from "@layouts/Layout.astro";
import { getCollection } from "astro:content";
export const prerender = false;
let path = Astro.url.pathname;
if (path.includes("/notebook/")) {
  const hashToHeal = path.match(/\/notebook\/.*?(\d{6})/)?.[1];
  if (hashToHeal) {
    const col = await getCollection("notes", (entry) => {
      return entry.data.selfHealing === hashToHeal;
    });

    if (col.length) {
      const redirect = "/notebook/" + col[0].slug;
      return Astro.redirect(redirect);
    }
  }
  return Astro.redirect("/404");
}
---
```

Before rendering my 404 page I will try to detect the self-healing ID and redirect to the collection available with this ID then in my normal URL I don't need to apply this but in the shareable link, I will include it because in other pages is common that the link is bad referenced.

For use this functionality we must me in hybrid mode.

> Thanks to [Tim Neubauer](https://timneubauer.dev/blog/copy-code-button-in-astro/) for the copy code button I use it only touching the css, and a little copilot refactor but it was great.