在 Laravel 5.1 上进行验证之前修改输入

我正在尝试在验证成功之前修改用户提交的输入。我已经遵循了这个简单的说明，但是当我在Laravel 5.1上测试它时，它不起作用。我做错了什么吗？

这是我的请求类SSHAM\Http\Requests\UserCreateRequest.php

<?php

namespace SSHAM\Http\Requests;

use SSHAM\Http\Requests\Request;

class UserCreateRequest extends Request
{

    // Some stuff not related with this problem

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules()
    {
        // Only for debug
        $prova = $this->all();
        echo "<pre>Inside Request - Before sanitize\n[" . $prova['public_key'] . "]</pre>\n";

        // Call a function to sanitize user input
        $this->sanitize();

        // Only for debug    
        $prova = $this->all();
        echo "<pre>Inside Request - After sanitize\n[" . $prova['public_key'] . "]</pre>\n";

        return [
            'username' => 'required|max:255|unique:users',
            'public_key' => 'openssh_key:public',
        ];
    }

    /**
     * Sanitizes user input. In special 'public_key' to remove carriage returns
     */
    public function sanitize()
    {
        $input = $this->all();

        // Removes carriage returns from 'public_key' input
        $input['public_key'] = str_replace(["\n", "\t", "\r"], '', $input['public_key']);

        $this->replace($input);
    }

}

这是我的自定义验证规则SSHAM\Providers\OpenSSHKeyValidatorServiceProvider.php

<?php

namespace SSHAM\Providers;

use Illuminate\Support\ServiceProvider;

class OpenSSHKeyValidatorServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap the application services.
     *
     * @return void
     */
    public function boot()
    {
        // Registering the validator extension with the validator factory
        \Validator::extend('openssh_key', function ($attribute, $value, $parameters) {

            // Some stuff not related with this problem    

            // Only for debug
            echo "<pre>Inside Validator value\n[" . $value ."]</pre>\n";
            dd();

            return true;
        });

    }

    // Some stuff not related with this problem    
}

当我调用调试时，我得到这个输出：

Inside Request - Before sanitize
[blah 
second line 
third line]

Inside Request - After sanitize
[blah second line third line]

Inside Validator value
[blah 
second line 
third line]

似乎正在工作，但是当在验证类上处理值时，它尚未被清理。sanitize()