Create Custom request to apply validation

CsvImportRequest.php

create file in App/Http/Requests/CsvImportRequest.php
<?php

namespace App\Http\Requests;

use Illuminate\Foundation\Http\FormRequest;

class CsvImportRequest 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()
    {
        return [
            'csv_file' => 'required|mimes:xlsx,xls,csv'
        ];
    }
}

in controller:
use App\Http\Requests\CsvImportRequest;
public function parseImport(CsvImportRequest $request)