Support next.config.js redirects, rewrites, headers

[scopsy]

First of all, thank you for the amazing work with this package!

Currently when defining experimental rewrites in next.config.js they are not respected in netlify and throw 404 error from netlify. Any chance they can be supported?

example of the config file:

module.exports = {
  target: 'serverless',
  experimental: {
    redirects() {
      const redirects = [
        {
          // Redirect root link with trailing slash to non-trailing slash, avoids 404 - See https://github.com/vercel/next.js/discussions/10651#discussioncomment-8270
          source: '/:locale/',
          destination: '/:locale',
          permanent: process.env.NEXT_PUBLIC_APP_STAGE !== 'development', // Do not use permanent redirect locally to avoid browser caching when working on it
        },
        {
          // Redirect link with trailing slash to non-trailing slash (any depth), avoids 404 - See https://github.com/vercel/next.js/discussions/10651#discussioncomment-8270
          source: '/:locale/:path*/',
          destination: '/:locale/:path*',
          permanent: true
        },
      ];

      return redirects;
    },
    rewrites() {
      const rewrites = [
        {
          source: '/',
          destination: '/api/autoRedirectToLocalisedPage',
        },
        {
          source: `/:locale((?!${noRedirectBasePaths.join('|')})[^/]+)(.*)`,
          destination: '/api/autoRedirectToLocalisedPage',
        },
      ];

      return rewrites;
    },
  },
};

[FinnWoelm]

Hey @scopsy,

Thank you for the kind words and for filing this issue to make next-on-netlify better 🙂

I had a closer look at the NextJS experimental syntax for redirects and rewrites as well as the limitations that apply to redirects on Netlify. There are a couple issues:

Netlify's redirect syntax is a lot more narrow than the one used by NextJS

Netlify only supports redirects with plain text, with parameter placeholders (/:id/:slug/:abc/...), and/or with match-all splats (/some/path/*). For example, the last rewrite you shared would not work on Netlify:

`/:locale((?!${noRedirectBasePaths.join('|')})[^/]+)(.*)`

There is no direct way to express that in a Netlify-compatible way. With Netlify, you would probably define it as a catch-all /* rewrite and position it after all other rewrites and redirects. Because Netlify only uses the first redirect/rewrite it finds and because of shadowing, Netlify would not apply the rewrite in any case where the user requests a page that actually exists.

So it's possible to express the same rewrite in Netlify, but I can't think of a way to automatically translate a redirect like the one you shared into the Netlify equivalent, correctly deciding if the rewrite should be at the very top or the very bottom of the list.

Netlify only redirects/rewrites once per request

I need to double check this, but my understanding is that Netlify only redirects or rewrites once per request. All server-side rendered pages and all pages with dynamic paths already require one redirect. For example, we may have a SSRed page called /users. That page gets turned into a serverless function and next-on-netlify creates a redirect for /users to /.netlify/functions/next_users . Now, if we try to add a redirect for /allusers to /users, Netlify will perform only that redirect, but not the /users -> /.netlify/functions/next_users one. It will try to serve users.html from the publish directory (out_public), not find it, and return 404.

One way to correct for that would be to evaluate the redirects at build-time. For example: next-on-netlify sees a redirect for /allusers to /users and next-on-netlify knows that we need to redirect /users to /.netlify/functions/next_users, so next-on-netlify writes the redirect as /allusers > /.netlify/functions/next_users. But that only works if the redirects are static. As soon as they are dyamic, using /:params or *-splat, this kind of evaluation becomes very difficult/impossible.

Next Steps

What do you think? Do you have ideas for how this could work? In your specific case, you could just work around it for now: The first two redirects are not needed for Netlify (because they normalize the URLs and trailing slashes anyway) and the last two rewrites you could manually add as one single rewrite in your netlify.toml:

[[redirects]]
  from = "/*"
  to = "/.netlify/functions/next_api_autoRedirectToLocalisedPage"
  status = 200

It would catch any unmatched path and call your API endpoint. Not what you were hoping for, I'm sure, but that's my best idea at the moment.

Let me know what you think!
- Finn

[joaogarin]

This is now fully supported (not experimental) in Nextjs. is this something that will be eventually added / supported? I would like to consider moving an app to netlify but currently it does use nextjs redirects and rewrites and so would be tricky not having those work anymore if I decide to move it =) thank you! happy netlify client ;)

[odenirdev]

i have the same problem of @scopsy

[odenirdev]

i need the rewrites next.config.js

[TimNZ]

To be clear: custom header in next.config.js are not supported?

headers: async () => {
	return [
		{
		source: "/(.*\\.(?:jpg|jpeg|png|gif))",
		headers: [
		{
			key: "Cache-Control",
			value: "public, max-age=3600",
		},
	],
	},
	]
	},