md.viewer permalinks lost on GN4 migration

[fgravin]

Describe the bug

Some permalinks are lost during GN4 migration:

In GN3, there was a service md.viewer which meant to load a formatter in a dedicated page with full static resources (javascript, css etc...).

This service has been removed in GN4. I haven't found any migration step to migrate the old permalinks to this service.

Furthermore, we can't forward those links from the Web application (urlrewrite.xml) because the # is not interpreted by the server.

I think that even the actual permalinks are not meaningful because of the # and might cause a problem one day, but that's another story.

To Reproduce

Link on V3: https://www.geocat.ch/geonetwork/srv/eng/md.viewer#/full_view/8698bf0b-fceb-4f0f-989b-111e7c4af0a4 Link on V4: https://apps.titellus.net/geonetwork/srv/fre/md.viewer#/full_view/18da353f-82c6-47a1-be7a-d07e9220932e

Expected behavior

Those links are still valid on GN4.

[fxprunayre]

"A permalink or permanent link is a URL that is intended to remain unchanged for many years into the future" (https://en.wikipedia.org/wiki/Permalink) so it was not a good idea to use such URLs for permalinks (as you said because of the # mainly). Also geocat.ch has issue with SEO so even if it is probably not only related to this type of URLs, you should recommend them to use more stable URL for permalinks as advertised in their sitemap https://www.geocat.ch/geonetwork/srv/api/sitemap?format=html&doc=1.

Maybe we should also make this more configurable as proposed by @josegar74 here https://github.com/geonetwork/core-geonetwork/pull/5579 and be more careful on settings canonical URL like in https://github.com/geonetwork/core-geonetwork/blob/main/web/src/main/webapp/xslt/common/render-html.xsl#L79

I don't think it make sense to restore this if it is to be used for permalink purposes.