Validation and precheck

Reject unsafe URLs when a user submits them. The rule passes when the guard lets the URL through (SafeFetch::allows()) and fails for anything that is not a string:

use RoundlyConsulting\SafeFetch\Rules\SafeUrl;

$request->validate(['feed' => ['required', 'string', 'max:2048', new SafeUrl]]);
$request->validate(['feed' => ['required', 'string', 'max:2048', 'safe_url']]);
$request->validate(['hook' => ['required', new SafeUrl(SafeFetch::policy()->allowHosts(['*.partner.example']))]]);
$request->validate(['hook' => ['required', SafeUrl::withoutLookup()]]);             // no DNS lookup
$request->validate(['dev_hook' => ['required', 'safe_url:http']]);                   // http as well

• One message whatever the reason — safe-fetch::validation.safe_url, “The :attribute must be a URL this application is allowed to fetch.” (Slovak too) — so the form never tells a user which internal names exist. A message you give the rule yourself wins.
• The string rule takes one parameter, http (safe_url:http → policy()->allowHttp()). Any other parameter throws InvalidArgumentException rather than being ignored.
• new SafeUrl(?DestinationPolicy $policy = null, bool $lookup = true) takes a policy of its own; call SafeFetch::vet() when you need the exact reason.
• The URL is judged again when it is fetched — DNS can change in between.

Without the DNS lookup

SafeUrl::withoutLookup(?DestinationPolicy $policy = null) judges through SafeFetch::precheck() instead: every rule except the lookup — the shape, scheme, port, blocked and app hosts, the allowlist, localhost, and an address literal in full. A form neither waits on DNS nor fails while a name does not resolve yet. Use it when a URL is stored now and called later:

$request->validate(['endpoint' => ['required', 'string', SafeUrl::withoutLookup($policy)]]);
$stored = SafeFetch::precheck($request->input('endpoint'), $policy)->toString();

precheck() returns the CanonicalUrl or throws DestinationRejected, and dispatches DestinationRefused with via precheck. A name it passes can still resolve privately — the guard judges it in full on every request. Use SafeFetch::vet() instead when the URL must resolve now.