URL object response type for Netlify edge functions

[Youhan]

Describe the feature

I was not sure if this goes to H3 or Nitro. Apologies if I am confused.

As per Netlify Edge functions documentation, the function can return a standard Response object or a URL object.
link: https://docs.netlify.com/edge-functions/api/#overview

The URL object is used for rewrites. For example, if you want to rewrite <username>.site.dev to www.side.dev/profile/<username>, they suggest using an edge function like this:

export default async (req : Request) => {
  const reqUrl = new URL(req.url)
  return new URL(`/profile/${reqUrl.hostname.split('.')[0]}/${reqUrl.pathname}`, 'https://www.site.dev/')
}

This function does not return a Response object, instead it returns a URL object. How that would be possible with Nitro/H3?

Here are links to Netlify example and docs:

• Docs: https://docs.netlify.com/edge-functions/api/#overview
• Rewrite example: https://github.com/netlify/edge-functions-examples/tree/main/pages/rewrite
• Rewrite Demo: https://edge-functions-examples.netlify.app/rewrite

Additional information

• Would you be willing to help implement this feature?

[serhalp]

@Youhan What are you trying to accomplish here? Nitro on Netlify will automatically turn configured redirects and rewrites into a configuration that Netlify understands, so they should work. Are you trying to return redirects/rewrites dynamically that can only be determined dynamically at runtime, hence needing to return a URL?

[Youhan]

Yes, that's correct. I am trying to rewrite the www.side.dev/profile/<username> to <username>.site.dev dynamically.

[pi0]

In an event handler you can use getRequestURL / sendRedirect

export default eventHandler(async (event) => {
  const reqUrl = getRequestURL(event);
  const newUrl = new URL(
    `/profile/${reqUrl.hostname.split(".")[0]}/${reqUrl.pathname}`,
    "https://www.site.dev/"
  );
  return sendRedirect(event, newUrl.href);
});

---

In h3 v2 / nitro v3:

• You can directly use event.url instead of getRequestURL(event)
• I made a feature request to investigate possibility of supporting return <URL> as redirect you can follow from here: Support URL as response unjs/h3#913

---