fix: Handle when required resource parameter is missing or empty

[joshtrichards]

• Resolves: Webfinger: Exception parse_str(): Argument #1 ($string) must be of type string, null given in file '/opt/nextcloud/apps/social/lib/WellKnown/WebfingerHandler.php' line [...] #1888
• Target version: master

Summary

resource is a required parameter. Avoid a 500 error when it's missing or empty. Instead generate a proper 400 bad request response.

Refs:

• https://datatracker.ietf.org/doc/html/rfc7033#section-4.2

P.S. Semi-related: Our default setup checks in server aren't compatible with social being enabled since they only check for 200 or 404 (neither of which are applicable when social is enabled and when querying /.well-known/webfinger without any parameterst):

https://github.com/nextcloud/server/blob/16812837157395c078a9689cd51530a6382e17d2/apps/settings/lib/SetupChecks/WellKnownUrls.php#L48

This PR doesn't impact those either way directly (since the prior 500 nor the 400 added via this PR would have ever passed). I'll try to take a closer look at those over in server. EDIT: nextcloud/server#49440

[cypress]

Social    Run #985

Run Properties:   Errored #985  •  4c35775a1f: fix: Handle when required `resource` parameter is missing or empty

Project	Social
Branch Review	fix-missing-resource-issue-1888
Run status	Errored #985
Run duration	01m 07s
Commit	4c35775a1f: fix: Handle when required `resource` parameter is missing or empty
Committer	Josh
View all properties for this run ↗︎

---

Test results
Failures	2
Flaky	0
Pending	0
Skipped	0
Passing	0
View all changes introduced in this branch ↗︎

[paulvt]

This did not help for me, the error I now get is:

[index] Error: parse_str(): Argument #1 ($string) must be of type string, null given in file '/var/www/html/custom_apps/social/lib/WellKnown/WebfingerHandler.php' line 228
	GET /index.php/.well-known/webfinger
	from [...] by -- at 21 Nov 2024, 21:03:53

[joshtrichards]

@paulvt Oops. Try now. :)

[paulvt]

Unfortunately still the same. And I see the static-psalm-analysis GitHub Action says that strings cannot be null too 😉

[joshtrichards]

Though I don't see how it should ever end up truly null. It should be ''. Even psalm agrees...

[oculos]

This did not help for me, the error I now get is:

[index] Error: parse_str(): Argument #1 ($string) must be of type string, null given in file '/var/www/html/custom_apps/social/lib/WellKnown/WebfingerHandler.php' line 228
	GET /index.php/.well-known/webfinger
	from [...] by -- at 21 Nov 2024, 21:03:53

Same for me.

[come-nc]

Suggested change

	$requestUri = $request->getRequestUri();
	if ($requestUri !== '') {
	parse_str(parse_url($requestUri, PHP_URL_QUERY) ?? '', $query);
	}
	parse_str(parse_url($request->getRequestUri(), PHP_URL_QUERY) ?? '', $query);

The if is not useful anymore, I think