fromRequest.md

laravel FormRequest 验证注解说明

FormRequestServiceProvider的运行过程

• 运行流程
  

在这里注册的ValidatesWhenResolved,FormRequest 它们都是属于Request类

• 验证器的使用
  

该验证器作为控制器的方法的参数controller->method(fromRequest) 时，在控制器调度时
会进行反射【由Container类处理,具体看控制器的依赖注入反射】进行运行其方法

然后运行如下代码

调用验证方法validate

• 验证器的验证

protected function validateAttribute($attribute, $rule)
    {
        $this->currentRule = $rule;

        list($rule, $parameters) = ValidationRuleParser::parse($rule);

        if ($rule == '') {
            return;
        }

        // First we will get the correct keys for the given attribute in case the field is nested in
        // an array. Then we determine if the given rule accepts other field names as parameters.
        // If so, we will replace any asterisks found in the parameters with the correct keys.
        if (($keys = $this->getExplicitKeys($attribute)) &&
            $this->dependsOnOtherFields($rule)) {
            $parameters = $this->replaceAsterisksInParameters($parameters, $keys);
        }

        $value = $this->getValue($attribute);

        // If the attribute is a file, we will verify that the file upload was actually successful
        // and if it wasn't we will add a failure for the attribute. Files may not successfully
        // upload if they are too large based on PHP's settings so we will bail in this case.
        if ($value instanceof UploadedFile && ! $value->isValid() &&
            $this->hasRule($attribute, array_merge($this->fileRules, $this->implicitRules))
        ) {
            return $this->addFailure($attribute, 'uploaded', []);
        }

        // If we have made it this far we will make sure the attribute is validatable and if it is
        // we will call the validation method with the attribute. If a method returns false the
        // attribute is invalid and we will add a failure message for this failing attribute.
        $validatable = $this->isValidatable($rule, $attribute, $value);

        if ($rule instanceof RuleContract) {
            return $validatable
                    ? $this->validateUsingCustomRule($attribute, $value, $rule)
                    : null;
        }

        $method = "validate{$rule}";

        if ($validatable && ! $this->$method($attribute, $value, $parameters, $this)) {
            $this->addFailure($attribute, $rule, $parameters);
        }
    }

具体验证方法详情

• 验证失败后的一个流程
  

当验证失败后，throw 一个验证异常类，这个时候被异常【自定义的异常处理类，框架在启动的时候
注册好了】捕获到，然后判断异常类型

返回的验证异常类最终是读取验证失败时保存的错误信息

针对错误验证时的消息重写

验证的大体原理
1、我们编写的表单验证类实际上是继承了FromRequest，它又继承了Request，它又继承了Symfony的Request类
同时它又继承了ValidatesWhenResolved 通过use继承的trait啦
2、它由FromRequestService服务提供器进行注册
3、当控制器调度时，会进行依赖注入【此时会反射即实例化验证类的子类如UserRequest 】，此时触发
第二步注册的匿名函数啦会招待request[继承]->validate()
4、会实例化验证器类，会把当前的请求数据，子类的验证规则rules,子类的验证错误提示获取到
5、循环所有的rules得到要验证的字段，要验证的数据，要验证的规则【对应函数】，规则的参数
6、验证失败后会将错误信息放在验证器的Message方法里
7、同时自动throw 一个ValidateException异常类，自然会被框架自定义的异常处理类捕获到
8、捕获到验证异常后，会进行处理，读取错误信息的数据响应返回
9、同时用户可以在App/Exceptions/Handler.php里重写父类的验证异常处理机制的