Yii源码阅读笔记（十五）

Model类，集中整个应用的数据和业务逻辑——验证

  /**
     * Returns the attribute labels.
     * 返回属性的标签
     *
     * Attribute labels are mainly used for display purpose. For example, given an attribute
     * `firstName`, we can declare a label `First Name` which is more user-friendly and can
     * be displayed to end users.
     * 属性标签主要用于显示目的，例如给属性'firstName'一个‘First Name’标签，能够更友好的显示给最终用户
     *
     * By default an attribute label is generated using [[generateAttributeLabel()]].
     * This method allows you to explicitly specify attribute labels.
     * 默认调用[[generateAttributeLabel()]]方法生成标签
     * Note, in order to inherit labels defined in the parent class, a child class needs to
     * merge the parent labels with child labels using functions such as `array_merge()`.
     * 注意，为了继承父类的标签，之类需要调用`array_merge()`合并父类的标签
     *
     * @return array attribute labels (name => label)
     * @see generateAttributeLabel()
     */
    public function attributeLabels()
    {
        return [];
    }

    /**
     * Returns the attribute hints.
     * 返回属性提示
     * Attribute hints are mainly used for display purpose. For example, given an attribute
     * `isPublic`, we can declare a hint `Whether the post should be visible for not logged in users`,
     * which provides user-friendly description of the attribute meaning and can be displayed to end users.
     * 属性提示主要用于显示目的，例如给一个属性`isPublic`，我们能够设置一个 `是否显示给最终用户` 的提示，
     * Unlike label hint will not be generated, if its explicit declaration is omitted.
     *
     * Note, in order to inherit hints defined in the parent class, a child class needs to
     * merge the parent hints with child hints using functions such as `array_merge()`.
     *
     * @return array attribute hints (name => hint)
     * @since 2.0.4
     */
    public function attributeHints()
    {
        return [];
    }

    /**
     * Performs the data validation.
     * 执行数据验证
     *
     * This method executes the validation rules applicable to the current [[scenario]].
     * 该方法执行指定场景下的数据验证
     * The following criteria are used to determine whether a rule is currently applicable:
     * 下面的标准来确定一个规则是否适用：
     *
     * - the rule must be associated with the attributes relevant to the current scenario;
     *   规则必须与当前场景相关的属性关联
     * - the rules must be effective for the current scenario.
     *   规则必须是有效的当前场景
     *
     * This method will call [[beforeValidate()]] and [[afterValidate()]] before and
     * after the actual validation, respectively. If [[beforeValidate()]] returns false,
     * the validation will be cancelled and [[afterValidate()]] will not be called.
     * 该方法会调用[[beforeValidate()]] 和[[afterValidate()]]方法
     *
     * Errors found during the validation can be retrieved via [[getErrors()]],
     * [[getFirstErrors()]] and [[getFirstError()]].
     * 验证的错误信息可以通过[[getErrors()]],[[getFirstErrors()]]和 [[getFirstError()]].方法获取
     *
     * @param array $attributeNames list of attribute names that should be validated.
     * If this parameter is empty, it means any attribute listed in the applicable
     * validation rules should be validated.
     * @param boolean $clearErrors whether to call [[clearErrors()]] before performing validation
     * @return boolean whether the validation is successful without any error.
     * @throws InvalidParamException if the current scenario is unknown.
     */
    public function validate($attributeNames = null, $clearErrors = true)
    {
        if ($clearErrors) {
            //清除所有的错误信息
            $this->clearErrors();
        }

        if (!$this->beforeValidate()) {
            //如果beforeValidate()返回false，则终止执行，返回false
            return false;
        }
        //取得所有场景及与之对应的 active 属性的列表
        $scenarios = $this->scenarios();
        //取得当前使用场景
        $scenario = $this->getScenario();
        if (!isset($scenarios[$scenario])) {
            //判断是否在场景列表中
            throw new InvalidParamException("Unknown scenario: $scenario");
        }

        if ($attributeNames === null) {
            //属性名为空，返回所有的active属性
            $attributeNames = $this->activeAttributes();
        }

        foreach ($this->getActiveValidators() as $validator) {
            //返回当前场景下的validator，然后遍历验证
            $validator->validateAttributes($this, $attributeNames);
        }
        //调用后置方法afterValidate();
        $this->afterValidate();

        return !$this->hasErrors();
    }

    /**
     * This method is invoked before validation starts.
     * 在验证方法前调用，触发`beforeValidate`事件，用于验证前的初步检查
     * The default implementation raises a `beforeValidate` event.
     * You may override this method to do preliminary checks before validation.
     * Make sure the parent implementation is invoked so that the event can be raised.
     * @return boolean whether the validation should be executed. Defaults to true.
     * If false is returned, the validation will stop and the model is considered invalid.
     */
    public function beforeValidate()
    {
        $event = new ModelEvent;
        $this->trigger(self::EVENT_BEFORE_VALIDATE, $event);

        return $event->isValid;
    }

    /**
     * This method is invoked after validation ends.
     * 在验证方法后调用，触发`afterValidate`事件，用于验证后的处理
     * The default implementation raises an `afterValidate` event.
     * You may override this method to do postprocessing after validation.
     * Make sure the parent implementation is invoked so that the event can be raised.
     */
    public function afterValidate()
    {
        $this->trigger(self::EVENT_AFTER_VALIDATE);
    }

    /**
     * Returns all the validators declared in [[rules()]].
     * 返回在[[rules()]]中定义的所有validators
     *
     * This method differs from [[getActiveValidators()]] in that the latter
     * only returns the validators applicable to the current [[scenario]].
     * 该方法不同于[[getActiveValidators()]] ，后者只返回当前场景下的validator
     *
     * Because this method returns an ArrayObject object, you may
     * manipulate it by inserting or removing validators (useful in model behaviors).
     * 该方法返回ArrayObject对象，可以进行添加或删除操作，例如：
     * For example,
     *
     * ```php
     * $model->validators[] = $newValidator;
     * ```
     *
     * @return ArrayObject|\yii\validators\Validator[] all the validators declared in the model.
     */
    public function getValidators()
    {
        if ($this->_validators === null) {
            //_validators中没有值，则调用createValidators()创建Validator
            $this->_validators = $this->createValidators();
        }
        return $this->_validators;
    }

    /**
     * Returns the validators applicable to the current [[scenario]].
     * 返回当前场景下的validator
     * @param string $attribute the name of the attribute whose applicable validators should be returned.
     * If this is null, the validators for ALL attributes in the model will be returned.
     * @return \yii\validators\Validator[] the validators applicable to the current [[scenario]].
     */
    public function getActiveValidators($attribute = null)
    {
        $validators = [];
        //获取当前模型的使用场景
        $scenario = $this->getScenario();
        foreach ($this->getValidators() as $validator) {
            if ($validator->isActive($scenario) && ($attribute === null || in_array($attribute, $validator->attributes, true))) {
                //获取当前场景下的validator
                $validators[] = $validator;
            }
        }
        return $validators;
    }

    /**
     * Creates validator objects based on the validation rules specified in [[rules()]].
     * 通过[[rules()]]中指定的验证规则生成验证对象
     * Unlike [[getValidators()]], each time this method is called, a new list of validators will be returned.
     * @return ArrayObject validators
     * @throws InvalidConfigException if any validation rule configuration is invalid
     */
    public function createValidators()
    {
        //创建ArrayObject实例
        $validators = new ArrayObject;
        foreach ($this->rules() as $rule) {
            //遍历[[rules()]]
            if ($rule instanceof Validator) {
                //如果$rule是Validator的实例，则直接写入$validators中
                $validators->append($rule);
            } elseif (is_array($rule) && isset($rule[0], $rule[1])) { // attributes属性, validator type验证类型
                //否则，调用Validator::createValidator生成Validator的实例
                $validator = Validator::createValidator($rule[1], $this, (array) $rule[0], array_slice($rule, 2));
                $validators->append($validator);
            } else {
                throw new InvalidConfigException('Invalid validation rule: a rule must specify both attribute names and validator type.');
            }
        }
        return $validators;
    }

    /**
     * Returns a value indicating whether the attribute is required.
     * 返回是否该属性值是required
     * This is determined by checking if the attribute is associated with a
     * [[\yii\validators\RequiredValidator|required]] validation rule in the
     * current [[scenario]].
     *
     * Note that when the validator has a conditional validation applied using
     * [[\yii\validators\RequiredValidator::$when|$when]] this method will return
     * `false` regardless of the `when` condition because it may be called be
     * before the model is loaded with data.
     *
     * @param string $attribute attribute name
     * @return boolean whether the attribute is required
     */
    public function isAttributeRequired($attribute)
    {
        foreach ($this->getActiveValidators($attribute) as $validator) {
            if ($validator instanceof RequiredValidator && $validator->when === null) {
                return true;
            }
        }
        return false;
    }

    /**
     * Returns a value indicating whether the attribute is safe for massive assignments.
     * 返回是否该属性值是批量操作安全的
     * @param string $attribute attribute name
     * @return boolean whether the attribute is safe for massive assignments
     * @see safeAttributes()
     */
    public function isAttributeSafe($attribute)
    {
        return in_array($attribute, $this->safeAttributes(), true);
    }

    /**
     * Returns a value indicating whether the attribute is active in the current scenario.
     * 返回是否该属性值是active
     * @param string $attribute attribute name
     * @return boolean whether the attribute is active in the current scenario
     * @see activeAttributes()
     */
    public function isAttributeActive($attribute)
    {
        return in_array($attribute, $this->activeAttributes(), true);
    }

    /**
     * Returns the text label for the specified attribute.
     * 返回指定属性的标签
     * @param string $attribute the attribute name
     * @return string the attribute label
     * @see generateAttributeLabel()
     * @see attributeLabels()
     */
    public function getAttributeLabel($attribute)
    {
        $labels = $this->attributeLabels();
        return isset($labels[$attribute]) ? $labels[$attribute] : $this->generateAttributeLabel($attribute);
    }

    /**
     * Returns the text hint for the specified attribute.
     * 返回指定属性的提示信息
     * @param string $attribute the attribute name
     * @return string the attribute hint
     * @see attributeHints()
     * @since 2.0.4
     */
    public function getAttributeHint($attribute)
    {
        $hints = $this->attributeHints();
        return isset($hints[$attribute]) ? $hints[$attribute] : '';
    }

    /**
     * Returns a value indicating whether there is any validation error.
     * 返回某个值是否有验证错误信息
     * @param string|null $attribute attribute name. Use null to check all attributes.
     * @return boolean whether there is any error.
     */
    public function hasErrors($attribute = null)
    {
        return $attribute === null ? !empty($this->_errors) : isset($this->_errors[$attribute]);
    }

    /**
     * Returns the errors for all attribute or a single attribute.
     * 返回全部或者某个属性的验证错误信息
     * @param string $attribute attribute name. Use null to retrieve errors for all attributes.
     * @property array An array of errors for all attributes. Empty array is returned if no error.
     * The result is a two-dimensional array. See [[getErrors()]] for detailed description.
     * @return array errors for all attributes or the specified attribute. Empty array is returned if no error.
     * Note that when returning errors for all attributes, the result is a two-dimensional array, like the following:
     * 错误信息的格式为二维数组，键名为属性值，键值为错误信息
     * ```php
     * [
     *     'username' => [
     *         'Username is required.',
     *         'Username must contain only word characters.',
     *     ],
     *     'email' => [
     *         'Email address is invalid.',
     *     ]
     * ]
     * ```
     *
     * @see getFirstErrors()
     * @see getFirstError()
     */
    public function getErrors($attribute = null)
    {
        if ($attribute === null) {
            return $this->_errors === null ? [] : $this->_errors;
        } else {
            return isset($this->_errors[$attribute]) ? $this->_errors[$attribute] : [];
        }
    }

    /**
     * Returns the first error of every attribute in the model.
     * 返回当前模型下每一个属性的第一条错误信息
     * @return array the first errors. The array keys are the attribute names, and the array
     * values are the corresponding error messages. An empty array will be returned if there is no error.
     * @see getErrors()
     * @see getFirstError()
     */
    public function getFirstErrors()
    {
        if (empty($this->_errors)) {
            return [];
        } else {
            $errors = [];
            foreach ($this->_errors as $name => $es) {
                if (!empty($es)) {
                    $errors[$name] = reset($es);
                }
            }

            return $errors;
        }
    }

    /**
     * Returns the first error of the specified attribute.
     * 返回指定属性的第一条错误信息
     * @param string $attribute attribute name.
     * @return string the error message. Null is returned if no error.
     * @see getErrors()
     * @see getFirstErrors()
     */
    public function getFirstError($attribute)
    {
        return isset($this->_errors[$attribute]) ? reset($this->_errors[$attribute]) : null;
    }

    /**
     * Adds a new error to the specified attribute.
     * 给指定的属性添加新的错误信息
     *
     * @param string $attribute attribute name
     * @param string $error new error message
     */
    public function addError($attribute, $error = '')
    {
        //将错误信息添加到errors数组中，键名为属性名[]，键值为错误信息
        $this->_errors[$attribute][] = $error;
    }

    /**
     * Adds a list of errors.
     * 添加错误信息列表
     * @param array $items a list of errors. The array keys must be attribute names.
     * The array values should be error messages. If an attribute has multiple errors,
     * these errors must be given in terms of an array.
     * You may use the result of [[getErrors()]] as the value for this parameter.
     * @since 2.0.2
     */
    public function addErrors(array $items)
    {
        foreach ($items as $attribute => $errors) {
            if (is_array($errors)) {
                foreach ($errors as $error) {
                    $this->addError($attribute, $error);
                }
            } else {
                $this->addError($attribute, $errors);
            }
        }
    }

    /**
     * Removes errors for all attributes or a single attribute.
     * 清除所有或者指定属性的错误信息
     * @param string $attribute attribute name. Use null to remove errors for all attribute.
     */
    public function clearErrors($attribute = null)
    {
        if ($attribute === null) {
            $this->_errors = [];
        } else {
            unset($this->_errors[$attribute]);
        }
    }