How to validate route parameters?

@erron you can create a route to /departments/delete/ and always return an error message that they need to pass the required parameter.

@erron it looks strange to me to expect route without required param. It this request comes from your application you should fix the reason - prevent the ability to send request without this param instead of trying to fix the result.

Or do you use it in api?

My thought

route:- Route::get('/departments/delete/{par1?}/{par2?}', 'TestController@testing');

Controller:

function testing($par1, $par2) {

if ($par1 == '') return back()->with('error', 'Please parameter');

// else

your code

I think https://laravel.com/docs/8.x/validation#quick-writing-the-validation-logic will solve your problem.