Install Strapi v5 in Sub-Path on Server not working

[JWandscheer]

Bug report

Required System information

• Node.js version: v18
• Strapi version: 5.0.0-rc.17
• Database: postgres
• Operating system: Linux
• Is your project Javascript or Typescript: Typescript

Describe the bug

Installing Strapi in a Sub-Path on a Server (f.e. https://rooturl.tld/backend) seems nearly unpossible. In a fresh install with server config url: https://rooturl.tld/backend/ and admin config admin-url: /admin (at build-time and runtime) the admin page generally loads (http 200) in /backend/admin, but the resources are loaded from the root path (https://rooturl.tld/strapi-BA4UeQmR.js). This leads to 404 and a blank page.

Steps to reproduce the behavior

1. Build Strapi with ENV URL=https:/rooturl.tld/backend/, ENV ADMIN_URL=/admin
2. Run Container
3. Admin Page is blank because js resources could not be loaded

Expected behavior

The resources should not ignore server-paths.

Code snippets

We are running strapi in a kubernetes cluster and have a rewrite in our virtual service:

- name: "backend-routes"
    match:
    - uri:
        prefix: "/backend/"
    rewrite:
      uri: "/"
    route:
    - destination:
        host: strapi-backend
        port:
          number: 1337

We already tried nearly all permutations in rewriting, ENV URL/ADMIN URL setting (like ADMIN_URL=/backend/admin) etc., but the initial javascript is always requested from the root url.

[alexandrebodin]

Can you please share full config in config/admin.js & config/server.js files .

[menflx]

We encountered the same problem when trying to host Strapi v5.0.3 under the subpath "/cms". Tried all possible combinations of absolute und relative URLs, but the admin page stays blank because the resources are still loaded from the root url.

config/admin.ts:

export default ({ env }) => ({
  auth: {
    secret: env('ADMIN_JWT_SECRET'),
  },
  apiToken: {
    salt: env('API_TOKEN_SALT'),
  },
  transfer: {
    token: {
      salt: env('TRANSFER_TOKEN_SALT'),
    },
  },
  url: env('ADMIN_URL'),
});

config/server.ts:

export default ({ env }) => ({
  host: env('HOST', '0.0.0.0'),
  port: env.int('PORT', 1337),
  app: {
    keys: env.array('APP_KEYS'),
  },
  url: env('PUBLIC_URL'),
  proxy: true,
  webhooks: {
    populateRelations: env.bool('WEBHOOKS_POPULATE_RELATIONS', false),
  },
});

For ADMIN_URL, we tried setting it to /admin, /admin/, http://localhost:1337/cms/admin, http://localhost:1337/cms/admin/.
For PUBLIC_URL, we tried setting it to http://localhost:1337/cms and http://localhost:1337/cms/.

[alexandrebodin]

Hi @menflx thanks for sharing your config I'll try to reproduce

[alexandrebodin]

We will review this community PR that seems to solve the issue #21507 as soon as we can