Summary

urlsrc is taken verbatim from Collabora's cached WOPI discovery document and used directly as the editor iframe's src. Because that value is an absolute URL, a Nextcloud instance reachable at more than one address can only ever open documents on one of them.

The chain

1. Service/DiscoveryService::getDiscoveryEndpoint() fetches /hosting/discovery from the single configured wopi_url, and the response is cached (CachedRequestService).
2. WOPI/Parser::getUrlSrcValue() returns the urlsrc attribute verbatim — the only transformation is str_replace('\.', '.', …).
3. That value reaches the front end as Config.get('urlsrc'), and src/helpers/url.js::getWopiUrl() concatenates it with the query parameters to form the iframe URL.
4. coolwsd emits an absolute URL in urlsrc, derived from the Host of the discovery request (or from server_name when set).

So the origin baked into step 4 is fixed for every user and every session, regardless of which address they actually reached Nextcloud on.

public_wopi_url does not help: Service/ConnectivityService::autoConfigurePublicUrl() derives it from urlsrc (domainOnly($determinedUrl)) to feed the CSP. It is an output of discovery, not an override of it.

Impact

Any deployment where Nextcloud is reachable at more than one origin — a LAN address and a public domain, a .onion, split-horizon DNS — gets a working editor on exactly one of them and a blank frame on the rest. Self-hosted setups hit this routinely.

Expected

A way to have the editor load same-origin, for deployments that reverse-proxy Collabora underneath the Nextcloud origin (/browser, /cool, /hosting). Either:

• an option to strip the scheme+host from urlsrc, leaving a root-relative URL the browser resolves against the current origin; or
• treat a configured public_wopi_url as an override applied to urlsrc, rather than a value derived from it.

Notes

A root-relative urlsrc appears to work with no other change: nothing in the path validates it as absolute, and AddContentSecurityPolicyListener already adds 'self' as a frame domain. domainOnly('/browser/…') returns '', which getDomainList()'s array_filter drops, so no stale CSP origin is added either.

I have this working by rewriting the discovery response in the reverse proxy (Apache mod_substitute, stripping the origin from urlsrc and favIconUrl) — documents open and edit correctly on every address simultaneously. That works, but it is a workaround for something that seems like it should be configurable.

Versions: richdocuments 11.1.0, Nextcloud 34.0.3, Collabora Online Development Edition 26.04.3.2.