Better source code documentation - Questions about how it works

[Vadorequest]

I've read https://zeit.co/blog/serverless-pre-rendering and I'm interested by SPR, but I don't fully understand how it works.

AFAIU, everything is done there https://github.com/zeit/spr-landing/blob/master/pages/index.js#L177-L180

  if (res) {
    res.setHeader("Cache-Control", "s-maxage=1, stale-while-revalidate");
    res.setHeader("X-version", etag);
  }

Few questions:

• What's the goal of X-version here? What happens if I don't define it?
• How does this cache implementation works? I don't understand how defining a 1s cache can change anything performance-wise.
• Basically, considering I have a Next.js app which does SSR (fetching content from a headless CMS in _app:getInitialProps), what would happen if I just add those two lines in _app/getInitialProps?

[timneutkens]

You can read more about it here: https://zeit.co/blog/serverless-pre-rendering

[Vadorequest]

Yeah, I saw, this link is how I heard of this project (as I stated in my post), but I still don't understand the technicals at hand.

[Siilwyn]

Just dug into this, the cache control header just signals the CDN to cache the whole page as stated in the blog post. The X-version header & etag are not needed unless you want to refresh the page client-side when the displayed page is out of date.

[ijjk]

Hey folks! We have upgraded this repo to take advantage of incremental static site generation (iSSG). In short:

• There’s never a cold boot anymore when accessing the page
• The page gets incrementally re-built asynchronously
• Always fast & available

This is thanks to Next.js' new hooks for static site generation, see the RFC here, where you can learn more about how this works.

I’m closing this issue for now as it’s no longer applicable. Feel free to ping me with any questions.