Laravel validation – how return back with errors from Request on fail?

On validation fail, I have 2 situations

• one when I display a new error page (this is how it was done before in the app)
• I have a form and I redirect back with input (my problem)

The app is catching the ValidationException in the exceptions Handler – so there is no back with errors for me if a request fails.
Now, I need to return back to the input with errors – from the request class, before it throws the standard ValidationException.

How do I do that from the request class pls?

The code is very basic

I have some rules…

I imagine I need a hook like – validationFailed().. in the request class?

Edit: – not API – regular monolithic PHP

<?php

namespace AppHttpRequests;

use IlluminateFoundationHttpFormRequest;
use Auth;

class LocationCodeRequest extends FormRequest
{
    /**
     * Determine if the user is authorized to make this request.
     *
     * @return bool
     */
    public function authorize()
    {
        return true;
    }

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules()
    {
        $user = Auth::user();

        return [
            'new_location_code' => 'required|string|max:255|exists:bars,code|not_in:' . $user->locationCode,
        ];
    }

    /**
     * Get the error messages for the defined validation rules.
     *
     * @return array
     */
    public function messages()
    {
        return [
            'new_location_code.not_in' => 'xxx',
            'new_location_code.exists' => 'yyy',
        ];
    }

    //I need something like this
    public function validationFailed()
    {
        return redirect()->back()->withErrors($this->validator)->withInput();;
    }
}