DangerousExtensions.php

<?php

namespace App\Rules;

use Illuminate\Contracts\Validation\Rule;

class DangerousExtensions implements Rule
{
    /**
     * @var array
     */
    public $extensions;

    /**
     * Array of common extensions that can be used to infect.
     *
     * @var array
     */
    protected $bad_extensions = [
        'exe',
        'sh',
        'jar',
        'dll',
        'tmp',
        'php',
        'py'
    ];

    /**
     * Create a new rule instance.
     *
     * @param array|null $extensions
     */
    public function __construct(?array $extensions = [])
    {
        $this->extensions = array_merge($this->bad_extensions, $extensions);
    }

    /**
     * Determine if the validation rule passes.
     *
     * @param  string  $attribute
     * @param  mixed  $value
     * @return bool
     */
    public function passes($attribute, $value)
    {
        return !in_array($value->getClientOriginalExtension(), $this->extensions);
    }

    /**
     * Get the validation error message.
     *
     * @return string
     */
    public function message()
    {
        return 'The :attribute file is a type that isn\'t allowed.';
    }
}