RFC: Support getStaticPaths fallback: 'blocking'

[strozw]

Is your feature request related to a problem? Please describe.

next.js 10 add support fallback blocking.
https://nextjs.org/blog/next-10#blocking-fallback-for-getstaticpaths

This feature is useful for SEO & OGP support.

Describe the solution you'd like

I want html response like existing ssg fallback.

Describe alternatives you've considered

We are considering whether to support it with SSR.
However, from a performance standpoint, I plan to give up OGP support and use SSG fallback for the time being.

Additional context

I'm trying this feature in following repository.
https://github.com/strozw/sample-serverless-nextjs

[arelaxend]

@danielcondemarin @dphang any updates for the next stable release ?
https://github.com/serverless-nextjs/serverless-next.js/projects/1

[dphang]

@arelaxend sorry I haven't had as much time this month but if you want to work on it, I'd be happy to review the PR. If not I can probably work on it once I have more time (maybe end of month or next month). Though fallback logic is a bit interesting since we are using origin request + origin response handler (actually we were thinking of trying to simplify to one handler).

For blocking fallback, I think we should check if fallback:blocking is enabled in origin request handler and render + save the response in S3, then return it.

[sinuheshinbr]

The implementation of this feature would be much appreciated!

[evangow]

@dphang I wrote some pseudocode to address { fallback: "blocking } along with setting a revalidation parameter in the issue here #804 (comment)