Make file-system based routes optional for custom servers

[gcpantazis]

Related to #913, and making a custom routing setup more generally:

If you're using a custom server per the README and examples, you may not want to keep the file-system based routes. This commit simply puts that behind a configuration setting, so that you could turn those routes off by the following config.next.js:

module.exports = {
    useFileSystemPageRoutes: false,
}

If this is an acceptable solution I can expand the tests to cover it — let me know if that's worth doing. Thanks again for all the hard work!

[timneutkens]

Think we can remove the !== false and add the default here https://github.com/zeit/next.js/blob/master/server/config.js#L6

[gcpantazis]

Done!

[timneutkens]

Awesome 🔥

[rauchg]

Some people might even be interested in customizing the name of the directory, for example:

"pagesDirectory": "screens"

i wonder if pagesDirectory: null could then accomplish this? Or do you think it's too obscure? That way we have fewer settings ;)

[timneutkens]

@rauchg that's interesting. pagesDirectory: null would be obscure. Though pagesDirectory: false might just be what we want in this situation 👍

[arunoda]

I really like #913. But when you add a custom route it'll get the priority over the page based old routing. So, I don't think, we need a special flag to disable it.

[gcpantazis]

@rauchg I dig the direction on using this to also customize pagesDirectory, agreed with @timneutkens on false as the value. I'll hook this up and update the tests.

@arunoda Hm, perhaps I'm misunderstanding but it seems like the custom server code needs to implement handle(req, res) to preserve the router's plumbing, which would persist all the file-system-based routes.

[arunoda]

Since we do handle(req, res) at the end this is fine.
Also, it's legit for users to both types of routing at the same time.

[nkzawa]

I think the pagesDirectory option is not suitable for this purpose, since you might want to change the directory and want to disable file-system based routes at the same time.

As @arunoda mentioned, you don't need the flag if you define customs routes over file-system based ones, though it would be inconvenient.

Another way is to set the option as an argument of handle like:

handle(req, res, { fileSystemRoutes: false })

[gcpantazis]

I think the pagesDirectory option is not suitable for this purpose, since you might want to change the directory and want to disable file-system based routes at the same time.

Ah, of course, that makes sense @nkzawa. I'm less sure if we want to add a secondary configuration into handle()'s arguments when we could just centralize it into next.config. (The need for it at all is probably a smell that the server router API needs to be expanded to allow for removing routes directly).

For now though, I'll proceed with adding the two options into next.config:

{
  pagesDirectory: 'foo', // default 'pages'
  useFileSystemPublicRoutes: false // default true
}

(Using the key useFileSystemPublicRoutes just since those routes would still exist for internal plumbing / your custom server routing code, they just wouldn't be exposed to users).

[nkzawa]

Let's not include pagesDirectory on this PR. I think it's a different feature and we should discuss it anyway.

[gcpantazis]

Sounds good @nkzawa, I'll split it into a separate PR and move that part of the discussion over there 👍

[timneutkens]

Looks good 👍

[timneutkens]

@nkzawa @arunoda leaving it to you to merge 👍

[timneutkens]

@arunoda can you check this one and merge if you want to take it 👍

[arunoda]

Okay. I'm good with this.

[sedubois]

Should documentation be added?

[arunoda]

@sedubois yeah! We can add it here in the options: https://github.com/zeit/next.js#custom-server-and-routing