Validation

Validate a request inline with Laravel's rule strings, or with typed rule objects from Rules:

final data = await request.validate({
  'email': 'required|email|unique:users',
  'password': 'required|min:8|confirmed',
  'role': [Rules.required(), Rules.inList(['admin', 'editor'])],
  'tags.*': 'string|max:20',
});
data.string('email'); // typed access to validated input only

Failures throw ValidationException, rendered as Laravel's 422 body:

{
  "message": "The email field is required. (and 1 more error)",
  "errors": {
    "email": ["The email field is required."],
    "password": ["The password field must be at least 8 characters."]
  }
}

The default English messages are identical to Laravel 12's lang/en/validation.php (checked by the conformance suite against the upstream file). Indonesian ships as the second locale: set request.attributes['locale'] = 'id' (for example in a middleware).

Semantics locked to Laravel#

• nullable stops the remaining rules when the value is null.
• A field that is absent and not required skips non-implicit rules; sometimes validates only when the key is present.
• confirmed looks for {field}_confirmation.
• bail stops at the first failure of a field.
• Nested data uses dot paths and * wildcards.

Form requests#

final class StorePostRequest extends FormRequest {
  const StorePostRequest();

  @override
  Map<String, Object> rules(Request request) => {
    'title': 'required|string|max:120',
    'body': 'nullable|string',
    'published': [Rules.sometimes(), Rules.boolean()],
  };
}

await FormRequest.run(const StorePostRequest(), request) runs authorize() (403 when it returns false), then the rules, and returns the validated data. dart run bin/dartisan.dart make:request StorePostRequest creates one.

Declare it on the route with .validates(const StorePostRequest()) instead and read request.validated() in the handler; see Routing.