vaadin-boot-example-gradle doesn't work without trailing slash in the URL

[mvysny]

• http://localhost/vaadin-boot-example-gradle/ - works and the app works properly.
• http://localhost/vaadin-boot-example-gradle - doesn't work and an empty page is shown

[mvysny]

Network traffic from app with the trailing slash:

Network traffic from app without the trailing slash:

[mvysny]

The problem is that in the latter case, the request for indexhtml.js goes to http://localhost/VAADIN/build/indexhtml.2ae6b87b.js while it should go to http://localhost/vaadin-boot-example-gradle/VAADIN/build/indexhtml.2ae6b87b.js

[mvysny]

Easiest workaround is to redirect to the URL with the trailing /

[mvysny]

Upstream ticket: vaadin/flow#15399

[mvysny]

The problem is that the index.html file links to vaadin js bootstrap via ./VAADIN/ relative URL which resolves to http://localhost/VAADIN/build/indexhtml.2ae6b87b.js when the request URL is
http://localhost/vaadin-boot-example-gradle (no trailing slash).

Possible solutions:

1. Vaadin redirects to url with trailing slash
2. The relative URL is generated in a different way when the url doesn't end with slash.
3. Something else :)
4. Modify reverse proxy to perform the redirect

[mvysny]

Workaround is to add a reverse-proxy rule which redirects to a path ending with a slash /: kubernetes/ingress-nginx#646 (comment)