一、创建表单验证自定义类

1) FormRequest「表单验证基类」

Create File: app/Http/Requests/FormRequest.php

# [可选] artisan 方式创建
php artisan make:request FormRequest

<?php
namespace App\Http\Requests;
use App\Http\Requests\SceneValidator;
use Illuminate\Foundation\Http\FormRequest as BaseFormRequest;
use Illuminate\Contracts\Validation\Validator;

class FormRequest extends BaseFormRequest
{
    use SceneValidator; // 此处见第二步

    /**
     * 判断用户是否有请求权限
     *
     * @return bool
     */
    public function authorize()
    {
        return true;
    }

    /**
     * 预设验证场景
     *
     * @return array
     */
    public function scene()
    {
        return [];
    }

	/**
     * [覆盖方法] 处理失败的验证
     *
     * @param  \Illuminate\Validation\Validator  $validator
     * @return void
     *
     * @throws \Illuminate\Validation\ValidationException
     */
    protected function failedValidation(Validator $validator)
    {
//        throw (new \Illuminate\Validation\ValidationException($validator))
//            ->errorBag($this->errorBag)
//            ->redirectTo($this->getRedirectUrl());
        abort(401, $validator->errors()->first());
    }
}

2) SceneValidator「表单场景验证Trait类」

Create File: app/Http/Requests/SceneValidator.php

# [可选] artisan 方式创建
php artisan make:request SceneValidator

<?php
namespace App\Http\Requests;
use Illuminate\Contracts\Validation\{Factory, Validator};

trait SceneValidator
{
    protected $scene = null;

    protected $onlyRule = [];

    protected $autoValidate = true;

    /**
     * Validate.
     *
     * @param string|array $scene
     */
    public function validate($scene = '')
    {
        if (!$this->autoValidate) {
            if (is_array($scene)) {
                $this->onlyRule = $scene;
            } else {
                $this->scene = $scene;
            }

            $this->handleValidate();
        }
    }

    /**
     * 覆盖 ValidatesWhenResolvedTrait->validateResolved
     */
    public function validateResolved()
    {
        if (method_exists($this, 'autoValidate')) {
            $this->autoValidate = $this->container->call([$this, 'autoValidate']);
        }

        if ($this->autoValidate) {
            $this->handleValidate();
        }
    }

    /**
     * Handle validate.
     */
    protected function handleValidate()
    {
        parent::validateResolved();
    }

    /**
     * 定义 FormRequest->getValidatorInstance 下 validator 验证器
     *
     * @param Factory $factory
     *
     * @return Validator
     */
    public function validator(Factory $factory)
    {
        $validationData = $this->isMethod('GET') ? $this->query() : $this->post();
        return $factory->make($validationData, $this->getRules(), $this->messages(), $this->attributes());
    }

    /**
     * Get rules.
     *
     * @return array
     */
    protected function getRules()
    {
        return $this->handleScene($this->container->call([$this, 'rules']));
    }

    /**
     * Handle scene.
     *
     * @param array $rules
     *
     * @return array
     */
    protected function handleScene(array $rules)
    {
        if ($this->onlyRule) {
            return $this->handleRules($this->onlyRule, $rules);
        }

        if (!empty($this->scene) && method_exists($this, 'scene')) {
            $scene = $this->container->call([$this, 'scene']);
            if (array_key_exists($this->scene, $scene)) {
                return $this->handleRules($scene[$this->scene], $rules);
            }
        }

        return $rules;
    }

    /**
     * Handle rules.
     *
     * @param array $sceneRules
     * @param array $rules
     *
     * @return array
     */
    protected function handleRules(array $sceneRules, array $rules)
    {
        $result = [];
        foreach ($sceneRules as $key => $value) {
            if (is_numeric($key) && array_key_exists($value, $rules)) {
                $result[$value] = $rules[$value];
            } else {
                $result[$key] = $value;
            }
        }

        return $result;
    }
}

3) UserRequest「示例，表单业务验证类」

Create File: app/Http/Requests/UserRequest.php

# [可选] artisan 方式创建
php artisan make:request UserRequest

<?php
namespace App\Http\Requests\User;
use App\Http\Requests\FormRequest;

class UserRequest extends FormRequest
{
    protected $autoValidate = false;

	/**
     * 应用于请求的验证规则
     *
     * @return array
     */
    public function rules()
    {
    	$_rules = [
            'account' => ['required','string'],
            'password' => 'required|string|min:6',
        ];
        if ($this->scene === 'register') {
        	// 注册时，增加账号重复验证
            $_rules['account'][] = 'unique:\App\Models\Users,account';
        }
        return $_rules;
    }

	/**
     * 获取验证错误的自定义属性
     *
     * @return array
     */
    public function attributes()
    {
        return [
            'account' => '用户账号',
            'password' => '用户密码',
        ];
    }

    /**
     * 获取已定义验证规则的错误消息
     *
     * @return array
     */
    public function messages()
    {
        return [
            'account.required' => ':attribute必填',
            'password.required'  => ':attribute必填',
        ];
    }

	/**
     * 预设验证场景
     *
     * @return array
     */
    public function scene()
    {
    	$_default = [
            'account',
            'password',
        ];
        return [
            'register' => $_default,
            'login' => $_default,
        ];
    }
}

二、创建控制器使用示例

Create File: app/Http/Controllers/UserController.php

# [可选] artisan 方式创建
php artisan make:controller UserController

//...
use App\Http\Requests\User\UserRequest;
//...
public function register(UserRequest $request)
{
    $params = $request->post();
    // 验证失败时，抛出异常\Illuminate\Validation\ValidationException
    $request->validate('register');
	// 获取验证通过数据：
	dump($request->validated());
	// 获取所有请求参数数据
    dd($params);
}
//...