fix: trim whitespace from domain names before saving hosts

[addielaruee]

Why

Fixes #5654.

When a domain/host is entered with a leading or trailing space (easy to do via copy‑paste), NPM stores the space verbatim. The generated nginx config then contains an invalid server_name/upstream, so the host saves but never loads — the user sees a misleading 502 that looks like an upstream problem rather than bad input.

Fix

The proxy_host, dead_host and redirection_host models each sorted domain_names in their $beforeInsert/$beforeUpdate hooks but never trimmed them, and certificate.js carried its own near‑identical (also untrimmed) cleanDomainNames.

This adds a single shared cleanDomainNames helper in backend/lib/helpers.js that:

• drops null/undefined entries,
• trims surrounding whitespace,
• removes any entry left empty after trimming,
• sorts,

and uses it across all four models, replacing the ad‑hoc per‑model .sort() and removing the duplicated copy in certificate.js. Trimming now applies consistently to every host type (and certificates) at the persistence layer.

Behaviour is a superset of the previous logic (which already filtered null and sorted), so existing well‑formed input is unaffected.

Verification

• biome lint passes on all five changed files.

• Unit-style checks of the helper:

  Input	Output
  [" example.com ", "b.com"]	["b.com", "example.com"]
  [" spaced.test "]	["spaced.test"]
  ["z.com", "a.com", ""]	["a.com", "z.com"]
  ["keep.com", null, " ", " x.io"]	["keep.com", "x.io"]
  undefined	[]

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Code refactoring
• API changes
• Performance improvement
• Test addition or update

AI Usage

• AI was used to write this
• AI was used to review this

[nginxproxymanagerci]

Docker Image for build 2 is available on DockerHub:

nginxproxymanager/nginx-proxy-manager-dev:pr-5742

Note

Ensure you backup your NPM instance before testing this image! Especially if there are database changes.
This is a different docker image namespace than the official image.

Warning

Changes and additions to DNS Providers require verification by at least 2 members of the community!

[jc21]

Thanks for taking the time to fix this.

I found 2 issues. Both come from the trimming being done too late: it happens in the model save hooks, after the duplicate-host check and schema validation have already run on the untrimmed names.

• backend/models/proxy_host.js:42 — Duplicate hosts can get through. The "already in use" check (internalHost.isHostnameTaken) runs before the model trims. So if host A already has example.com and someone creates host B with example.com plus a trailing tab, the check finds no match. Host B is then saved as plain example.com, two hosts share one server_name, and nginx serves only one of them. The same applies to dead_host.js and redirection_host.js.
• backend/lib/helpers.js:68 — Trimming can undo what the schema guarantees. The schema requires at least one name and no repeats, but it checks before trimming. So ['a.com', 'a.com\t'] is saved as ['a.com', 'a.com']. And ['\t'] is saved as an empty list, which renders an empty server_name ;, so the nginx config fails to load and the host is broken again.

The regex pattern for domain_names in backend/schema/common.json already rejects a literal space. So the copy-pasted leading or trailing spaces from issue #5654 may already be refused by the API before these hooks run, and the new trimming would only ever act on other whitespace such as tabs. That's worth checking against the actual reproduction before merging.