Optimized assets hashing policy (netlify)

[Rigo-m]

As stated in many discussions in netlify forums (https://answers.netlify.com/t/support-guide-why-do-i-see-uncaught-syntaxerror-unexpected-token-errors-how-can-i-use-chunking-or-versioning-for-my-assets-at-netlify/124 for example), netlify handles cache busting on assets on it's own via the ETAG/if-none-match headers combo.
Meaning it will respond with a 304 or a 200 with the new asset based on the hash sent.
Although build-time-assets-cache-busting via build hash in the filename works most of the times, it becomes a kind of a problem with lazy components/dynamic imports. This, in nuxt, is already handled via the chunk-error plugin that reloads the application whenever a chunk error appears.
But: respecting netlify proposal for the assets cache handling seems a more sane approach to me (especially when a website has a high "build-rate" e.g. 4/5 builds a day)
We found that removing hash in filenames via vite:

vite: {
  build: {
      rollupOptions: {
        output: {
          chunkFileNames: '_nuxt/[name].js',
          entryFileNames: '_nuxt/[name].js',
          assetFileNames: '_nuxt/[name].[ext]',
        },
      },
 }

and changing nitro's default headers via netlify.toml

[[headers]]
  for = "_nuxt/*"
  [headers.values]
    cache-control = "public, max-age=0, must-revalidate"

[[headers]]
  for = "_scripts/*"
  [headers.values]
    cache-control = "public, max-age=0, must-revalidate"

worked best in our case.

I'm keen to know what would be the best approach going forward for the netlify preset.
@pi0 @serhalp

[pi0]

Currently, it is possible to generatethe same _headers file using this config:

export default defineNitroConfig({
  publicAssets: [
    {
      baseURL: "_nuxt",
      // autoHeaders: true, // (proposal below)
    },
  ],
  routeRules: {
    "/_nuxt/**": {
      headers: {
        "cache-control": "public, max-age=0, must-revalidate",
      },
    },
  },
});

Since these kinds of headers are also related to the frontend build (nuxt/vite), Nitro itself cannot directly modify behavior without any hints.

I think we can introduce autoHeaders: true for publicAssets dirs that can set maxAge automatically:

• Avoid header for fallthorough dirs
• Use a long TTL by default
• Override with max-age=0, must-revalidate in netlify preset

Nuxt can itself today also achieve behavior above without involving Nitro but this would allow it to avoid having vendor-specific logic and let nitro smartly decide about dirs. (and enables same benefit for all other frameworks based on nitro for netlify preset)

We might also enable autoHeaders flag by default in next major version.

[Rigo-m]

This seems interesting.
What are your thoughts on the removal of name hashing in atomic-deploys environments presets?

[pi0]

Nitro does not emit/configure hashes for public assets do you mean to force rename them?

[Rigo-m]

Nuxt does, I guess it's in framework-land configuration then.
So nuxt would be in charge of, eventually, removing assets hashing based on nitro's preset?
Also, would love to know what's your take on that, since you're so knowledgeable about deploy environments: do you think the best practice would be to hash assets anyway in atomic-deployments environments or hashing assets is anyway the way to go?
More thoughts by rich harris here: sveltejs/kit#3130
Thank in advance Pooya for your precious time

[pi0]

Hmm, that's a good point we can also give that hint to nuxt for example so it knows if, in the next step, hashes can be safely removed.

TBH I haven't tried Netlify/Vercel solutions, it seems they provide completely different ways (Skew Protection in vercel vs cache-control in Netlify) so kinda tricky to jump onto decision without experimenting end-to-end. But thanks for initiating it, I think it is now clear what we need from the Nitro side in the first step:

• A utility to expose vendor feature flags (used by Nuxt in the first step of building client)
• A shorthand flag for nitro public assets with smart (preset-aware) headers

[Rigo-m]

As always: let me know how/if I can be of any help!