added empty_with validator

[willemo]

I've added an empty_with validator that checks if either the field under validation is empty or all of the other specified fields. With this validator you can make an either [this field] or [that field] validation.

[olivervogel]

Can you describe a use case for this?

[willemo]

Sure! I'm using it for manual or stored filters when doing a GET request to my API:

You can either make this request: GET /endpoint?foo=bar&baz=123

Or make this request: GET /endpoint?filter_id=321

If you'd do both in the same request, the validator would fail.

You can set it up like so:

$validator = Validator::make($request->all(), [
    'foo' => 'string|nullable|empty_with:filter_id',
    'baz' => 'integer|nullable|empty_with:filter_id',
    'filter_id' => 'integer|nullable|exists:filters,id',
]);

The filter_id field doesn't need an empty_with validator, since that's being covered by the other fields having it.

[olivervogel]

Sounds good.