basePath option is not working

[vitorbal]

Describe the bug
If you set up a very simple nextjs app with the basePath option configured, the deployed website will 404 a bunch of static asset paths. Here's an example for a basePath of /cats-of-zapier:

To Reproduce
Steps to reproduce the behavior:

1. Create a new next.js app
2. Add basePath: '/foo' to next.config.js
3. Deploy the app to netlify
4. Navigate to the deployment and notice how all of the prefixed assets 404

Expected behavior
For the app to be served correctly, with no 404s.

Versions

• Next.js: 10.0.7
• plugin (if installed at fixed version): latest, I guess? Enabled from the Netlify UI

[jlengstorf]

hey, @vitorbal! do you have a reproduction available for us to review? and/or the build logs for the failing deploy? that helps us track things down much more quickly

thank you!

[jdeal]

@vitorbal does this forum post help?

[vitorbal]

@jlengstorf thanks!

• reproduction case: https://github.com/vitorbal/netlify-next-basepath
• app deployed on netlify: https://604defe6294def94d336b2a7--hungry-chandrasekhar-0c40c1.netlify.app/
• build logs: https://gist.github.com/vitorbal/4cf9edbaa6e205eb0c8707a3e956d753

as you can see / is serving what should be served by /foo, and all the static assets 404. If you try navigating to /foo, it 404s, so something is wrong with the runtime there.

[vitorbal]

@jdeal thanks for sharing that forum post! It sort of helps, but in their case, they are deploying an app via next export. I'm interested in deploying a next app in serverless mode, so this plugin can be leveraged to support SSRd pages, etc.

[jlengstorf]

hey, @vitorbal — I think I know the issue here. with basePath, the assumption is that the site will be served from https://example.com/foo/, so you'd redirect to your app like so:

/foo/*  https://604defe6294def94d336b2a7--hungry-chandrasekhar-0c40c1.netlify.app/:splat  200

I set up an example of this:

• parent site (redirects to the next site at /foo): https://keen-hamilton-aebe60.netlify.app/foo
• Next site: https://adoring-bardeen-d8f372.netlify.app/

source code:

• parent site: https://github.com/jlengstorf/next-basepath-poc
• Next site is a fork of your repro

let me know if this makes sense. thanks!

[lindsaylevine]

hey @vitorbal! did jason's comment solve your issue? let us know so we can close the issue or continue to try to help! :D

[vitorbal]

Howdy folks! Apologies for the lul.

@jlengstorf I checked out your app and even though it solves the problem, I would expect a standalone next.js app to work without those redirects.

If you run your next app locally, the basePath config works without a problem, so I would expect it to work once deployed too. Similarly, if you deploy your next app to a node server instead of a serverless platform like Netlify, the basePath config also works without any redirects.

If it helps, I deployed the reproduction case to Vercel and it also works as expected there: https://next-basepath.vercel.app/foo

[lunelson]

@vitorbal @jlengstorf I've just run in to this too. I don't think redirecting from root to a subpath is the right solution. When I run next build and then next start on my site locally, it serves the built site under the subpath (in my case /blog), and that's the way it should work here too. Also: please verify the solution with the trailingSlash: true setting as well

[lindsaylevine]

@vitorbal @lunelson hello! i'll explore how we might solve this within the plugin. will let you know!!!

[vitorbal]

@lindsaylevine @jlengstorf sounds good, thank you both for being so responsive!