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Merge pull request #5330 from yii2-chinesization/master

New Chinese translations and new enhancement for old docs
parents 5866178b d339ab8d
Showing with 2542 additions and 81 deletions
docs/guide-zh-CN/README.md
......@@ -28,7 +28,7 @@ Yii 2.0 权威指南
应用结构
--------
* **已定稿** [结构总览](structure-overview.md)
* **已定稿** [结构概述](structure-overview.md)
* **已定稿** [入口脚本](structure-entry-scripts.md)
* **已定稿** [应用](structure-applications.md)
* **已定稿** [应用组件](structure-application-components.md)
......@@ -44,11 +44,12 @@ Yii 2.0 权威指南
请求处理
--------
* **待定中** [引导（Bootstrapping）](runtime-bootstrapping.md)
* **待定中** [路由（Routing）](runtime-routing.md)
* **待定中** [请求（Request）](runtime-requests.md)
* **待定中** [响应（Response）](runtime-responses.md)
* **待定中** [Sessions（会话）和 Cookies](runtime-sessions-cookies.md)
* **已定稿** [运行概述](runtime-overview.md)
* **已定稿** [引导（Bootstrapping）](runtime-bootstrapping.md)
* **已定稿** [路由（Routing）](runtime-routing.md)
* **已定稿** [请求（Request）](runtime-requests.md)
* **已定稿** [响应（Response）](runtime-responses.md)
* **已定稿** [Sessions（会话）和 Cookies](runtime-sessions-cookies.md)
* **编撰中** [URL 解析和生成](runtime-url-handling.md)
* **编撰中** [错误处理](runtime-handling-errors.md)
* **编撰中** [日志](runtime-logging.md)
......@@ -89,7 +90,7 @@ Yii 2.0 权威指南
显示数据
--------
* **待定中** [格式化输出数据](output-formatting.md)
* **待定中** [格式化输出数据](output-formatter.md)
* **待定中** [分页（Pagination）](output-pagination.md)
* **待定中** [排序（Sorting）](output-sorting.md)
* **编撰中** [数据提供器](output-data-providers.md)
......
docs/guide-zh-CN/intro-upgrade-from-v1.md
......@@ -11,7 +11,7 @@
安装
------------
Yii 2.0 完全拥抱 [Composer](https://getcomposer.org/)，它是PHP中的一个依赖管理工具。核心框架以及扩展的安装都通过 Composer 来处理。想要了解更多如何安装 Yii 2.0 请参阅本指南的 [安装 Yii](start-installation.md) 章节。如果你想创建新扩展，或者把你已有的 Yii 1.1 的扩展改写成兼容 2.0 的版本，你可以参考 [创建扩展](extend-creating-extensions.md) 章节。
Yii 2.0 完全拥抱 [Composer](https://getcomposer.org/)，它是事实上的 PHP 依赖管理工具。核心框架以及扩展的安装都通过 Composer 来处理。想要了解更多如何安装 Yii 2.0 请参阅本指南的 [安装 Yii](start-installation.md) 章节。如果你想创建新扩展，或者把你已有的 Yii 1.1 的扩展改写成兼容 2.0 的版本，你可以参考 [创建扩展](extend-creating-extensions.md) 章节。
PHP 需求
......@@ -33,17 +33,17 @@ Yii 2.0 需要 PHP 5.4 或更高版本，该版本相对于 Yii 1.1 所需求的
命名空间
---------
Yii 2.0 里最明显的改动就数命名空间的使用了。几乎每一个核心类都引入了命名空间，比如 `yii\web\Request`。1.1 版用于类名前的字母 “C” 已经不再使用。当前的命名规范与目录结构相吻合。例如，`yii\web\Request` 就表明对应的类文件是 Yii 框架文件夹下的 `web/Request.php` 文件。
Yii 2.0 里最明显的改动就数命名空间的使用了。几乎每一个核心类都引入了命名空间，比如 `yii\web\Request`。1.1 版类名前缀 “C” 已经不再使用。当前的命名方案与目录结构相吻合。例如，`yii\web\Request` 就表明对应的类文件是 Yii 框架文件夹下的 `web/Request.php` 文件。
（有了 Yii 的类自动加载器，你可以直接使用全部核心类而不需要显式包含具体文件。）
有了 Yii 的类自动加载器，你可以直接使用全部核心类而不需要显式包含具体文件。
组件（Component）与对象（Object）
--------------------
Yii 2.0 把 1.1 里的 `CComponent` 类拆分成了两个类：[[yii\base\Object]] 和 [[yii\base\Component]]。[[yii\base\Object|Object]] 类是一个轻量级的基类，你可以通过 getters 和 setters 来定义 [object 的属性](concept-properties.md)。[[yii\base\Component|Component]] 类继承自 [[yii\base\Object|Object]]，同时进一步支持 [事件](concept-events.md) 和 [行为](concept-behaviors.md)。
Yii 2.0 把 1.1 中的 `CComponent` 类拆分成了两个类：[[yii\base\Object]] 和 [[yii\base\Component]]。[[yii\base\Object|Object]] 类是一个轻量级的基类，你可以通过 getters 和 setters 来定义[对象的属性](concept-properties.md)。[[yii\base\Component|Component]] 类继承自 [[yii\base\Object|Object]]，同时进一步支持 [事件](concept-events.md) 和 [行为](concept-behaviors.md)。
如果你不需要用到事件或行为，应该考虑使用 [[yii\base\Object|Object]] 类作为基类。这通常是表示基本数据结构的类。
如果你不需要用到事件或行为，应该考虑使用 [[yii\base\Object|Object]] 类作为基类。这种类通常用来表示基本的数据结构。
对象的配置
......@@ -65,12 +65,12 @@ class MyClass extends \yii\base\Object
{
parent::init();
// ...配置生效后的初始化过程
// ... 配置生效后的初始化过程
}
}
```
在上面的例子里，构造方法的最后一个参数必须输入一个配置数组，包含一系列用于在方法结尾初始化相关属性的键值对。你可以重写 [[yii\base\Object::init()|init()]] 方法来执行一些需要在配置生效后进行的初始化工作。
在上面的例子里，构造方法的最后一个参数必须传入一个配置数组，包含一系列用于在方法结尾初始化相关属性的键值对。你可以重写 [[yii\base\Object::init()|init()]] 方法来执行一些需要在配置生效后进行的初始化工作。
你可以通过遵循以下约定俗成的编码习惯，来使用配置数组创建并配置新的对象：
......@@ -95,11 +95,11 @@ $event = new \yii\base\Event;
$component->trigger($eventName, $event);
```
要给事件附加一个事件句柄（Event Handler 或者叫事件处理器），需要使用 [[yii\base\Component::on()|on()]] 方法：
要给事件附加一个事件事件处理器，需要使用 [[yii\base\Component::on()|on()]] 方法：
```php
$component->on($eventName, $handler);
// 要解除相关句柄，使用 off 方法：
// 解除事件处理器，使用 off 方法：
// $component->off($eventName, $handler);
```
......@@ -174,7 +174,7 @@ public function actionView($id)
}
```
请查看 [控制器（Controller）](structure-controllers.md) 章节了解有关控制器的更多细节。
请查看[控制器（Controller）](structure-controllers.md)章节了解有关控制器的更多细节。
小部件（Widget）
......@@ -283,7 +283,7 @@ Yii 2.0 很多常用的静态助手类，包括：
表单
-----
Yii 2.0 引进了**表单栏（field）**的概念，用来创建一个基于 [[yii\widgets\ActiveForm]]的表单。一个表单栏是一个由标签、输入框、错误消息（可能还有提示文字）组成的容器，被表示为 [[yii\widgets\ActiveField|ActiveField]] 对象。使用表单栏建立表单的过程比以前更整洁利落：
Yii 2.0 引进了**表单栏（field）**的概念，用来创建一个基于 [[yii\widgets\ActiveForm]] 的表单。一个表单栏是一个由标签、输入框、错误消息（可能还有提示文字）组成的容器，被表示为一个 [[yii\widgets\ActiveField|ActiveField]] 对象。使用表单栏建立表单的过程比以前更整洁利落：
```php
<?php $form = yii\widgets\ActiveForm::begin(); ?>
......@@ -327,14 +327,14 @@ Yii 2.0 的[活动记录](db-active-record.md)改动了很多。两个最显而
1.1 中的 `CDbCriteria` 类在 Yii 2 中被 [[yii\db\ActiveQuery]] 所替代。这个类是继承自 [[yii\db\Query]]，因此也继承了所有查询生成方法。开始拼装一个查询可以调用 [[yii\db\ActiveRecord::find()]] 方法进行：
```php
// 检索所有 *活动的* 客户和订单，并以 ID 排序：
// 检索所有“活动的”客户和订单，并以 ID 排序：
$customers = Customer::find()
->where(['status' => $active])
->orderBy('id')
->all();
```
要声明一个关联关系，只需简单地定义一个 getter 方法来返回一个 [[yii\db\ActiveQuery|ActiveQuery]] 对象。getter 方法定义的属性名（译者注：即 getOrders() 中的 orders）表示关联关系名。如，以下代码声明了一个名为 `orders` 的关系（1.1 中必须在 `relations()` 方法内声明关系）：
要声明一个关联关系，只需简单地定义一个 getter 方法来返回一个 [[yii\db\ActiveQuery|ActiveQuery]] 对象。getter 方法定义的属性名代表关联表名称。如，以下代码声明了一个名为 `orders` 的关系（1.1 中必须在 `relations()` 方法内声明关系）：
```php
class Customer extends \yii\db\ActiveRecord
......@@ -360,7 +360,7 @@ $orders = $customer->getOrders()->andWhere('status=1')->all();
$customers = Customer::find()->asArray()->all();
```
另一个改变是你不能再通过公共数据定属性（Attribute）的默认值了。如果你需要这么做的话，可以在你的记录类的 `init` 方法中设置它们。
另一个改变是你不能再通过公共变量定义属性（Attribute）的默认值了。如果你需要这么做的话，可以在你的记录类的 `init` 方法中设置它们。
```php
public function init()
......@@ -370,11 +370,41 @@ public function init()
}
```
曾几何时，在 1.1 中重写一个活动记录类的构造方法（Constructor）会导致一些问题。它们不会在 2.0 中出现了。需要注意的是，如果你需要在构造方法中添加一些参数，恐怕必须重写 [[yii\db\ActiveRecord::instantiate()]] 方法。
曾几何时，在 1.1 中重写一个活动记录类的构造方法会导致一些问题。它们不会在 2.0 中出现了。需要注意的是，如果你需要在构造方法中添加一些参数，恐怕必须重写 [[yii\db\ActiveRecord::instantiate()]] 方法。
活动记录方面还有很多其他的变化与改进，请参考[活动记录](db-active-record.md)章节以了解更多细节。
活动记录行为（Active Record Behaviors）
------------------------------------
在 2.0 中遗弃了活动记录行为基类 `CActiveRecordBehavior`。如果你想创建活动记录行为，需要直接继承 `yii\base\Behavior`。如果行为类中需要表示一些事件，需要像这样覆写 `events()` 方法：
```php
namespace app\components;
use yii\db\ActiveRecord;
use yii\base\Behavior;
class MyBehavior extends Behavior
{
// ...
public function events()
{
return [
ActiveRecord::EVENT_BEFORE_VALIDATE => 'beforeValidate',
];
}
public function beforeValidate($event)
{
// ...
}
}
```
用户及身份验证接口（IdentityInterface）
-------------------------------------
......@@ -401,4 +431,4 @@ Yii 2.0 的 URL 管理跟 1.1 中很像。一个主要的改进是现在的 URL
同时使用 Yii 1.1 和 2.x
----------------------
如果你有一些遗留的 Yii 1.1 代码，需要跟 Yii 2.0 一起使用，可以参考 [1.1 和 2.0 共用](extend-using-v1-v2.md)章节。
如果你有一些遗留的 Yii 1.1 代码，需要跟 Yii 2.0 一起使用，可以参考 [1.1 和 2.0 共用](tutorial-yii-integration.md)章节。
docs/guide-zh-CN/intro-yii.md
Yii 是什么
===========
Yii 是一个高性能，基于组件的 PHP 框架，用于快速开发现代 Web 应用程序。名字 Yii （读作 `易`）在中文里有 “极致简单与不断演变” 两重含义，也可看作 **Yes It Is**! 的缩写。
Yii 是一个高性能，基于组件的 PHP 框架，用于快速开发现代 Web 应用程序。名字 Yii （读作 `易`）在中文里有“极致简单与不断演变”两重含义，也可看作 **Yes It Is**! 的缩写。
Yii 最适合做什么？
---------------------
Yii 是一个通用的 Web 编程框架，即可以用于开发各种基于 PHP 的 Web 应用。因为基于组件的框架结构和设计精巧的缓存支持，Yii 特别适合开发大型应用，如门户网站、论坛、内容管理系统（CMS）、电子商务项目和 RESTful Web 服务等。
Yii 是一个通用的 Web 编程框架，即可以用于开发各种基于 PHP 的 Web 应用。因为基于组件的框架结构和设计精巧的缓存支持，它特别适合开发大型应用，如门户网站、社区、内容管理系统（CMS）、电子商务项目和 RESTful Web 服务等。
Yii 和其他框架相比呢？
-------------------------------------------
如果你有其它框架使用经验，那么你会很开心看到 Yii 所做的努力：
- 和其他 PHP 框架类似，Yii 实现了 MVC（Model-View-Controller）设计模式并基于该模式组织代码。
- Yii 的代码简洁优雅，这是 Yii 的编程哲学。它永远不会为了要迎合某个设计模式而对代码进行过度的设计。
- Yii 是一个全栈框架，提供了大量久经考验，开箱即用的特性，例如：对关系型和 NoSQL 数据库都提供了查询生成器（QueryBuilders）和 ActiveRecord；RESTful API 的开发支持；多层缓存支持，等等。
- Yii 的代码简洁优雅，这是它的编程哲学。它永远不会为了严格遵照某种设计模式而对代码进行过度的设计。
- Yii 是一个全栈框架，提供了大量久经考验，开箱即用的特性：对关系型和 NoSQL 数据库都提供了查询生成器和 ActiveRecord；RESTful API 的开发支持；多层缓存支持，等等。
- Yii 非常易于扩展。你可以自定义或替换几乎任何一处核心代码。你还会受益于它坚实可靠的扩展架构，使用、再开发或再发布扩展。
- 高性能始终是 Yii 的首要目标之一。
Yii 不是一场独角戏，它由一个[强大的开发者团队](http://www.yiiframework.com/about/)提供支持，也有一个庞大的专家社区，持续不断地对 Yii 的开发作出贡献。Yii 开发者团队始终对 Web 开发最新潮流和其他框架及项目中的最佳实践和特性保持密切关注，那些有意义的最佳实践及特性会被不定期的整合进核心框架中，并提供简单优雅的接口。
Yii 不是一场独角戏，它由一个[强大的开发者团队](http://www.yiiframework.com/about/)提供支持，也有一个庞大的专家社区，持续不断地对 Yii 的开发作出贡献。Yii 开发者团队始终对 Web 开发趋势和其他框架及项目中的最佳实践和特性保持密切关注，那些有意义的最佳实践及特性会被不定期的整合进核心框架中，并提供简单优雅的接口。
Yii 版本
------------
Yii 当前有两个主要版本：1.1 和 2.0。 1.1 版是上代的老版本，现在处于维护状态。2.0 版是一个完全重写的版本，采用了最新的技术和协议，包括依赖包管理器（Composer）、PHP 代码规范（PSR）、命名空间、Traits（特质）等等。 2.0 版代表了最新一代框架，是未来几年中我们的主要开发版本。本指南主要基于 2.0 版编写。
Yii 当前有两个主要版本：1.1 和 2.0。 1.1 版是上代的老版本，现在处于维护状态。2.0 版是一个完全重写的版本，采用了最新的技术和协议，包括依赖包管理器 Composer、PHP 代码规范 PSR、命名空间、Traits（特质）等等。 2.0 版代表新一代框架，是未来几年中我们的主要开发版本。本指南主要基于 2.0 版编写。
系统要求和先决条件
......@@ -32,5 +34,5 @@ Yii 当前有两个主要版本：1.1 和 2.0。 1.1 版是上代的老版本，
Yii 2.0 需要 PHP 5.4.0 或以上版本支持。你可以通过运行任何 Yii 发行包中附带的系统要求检查器查看每个具体特性所需的 PHP 配置。
使用 Yii 需要对面向对象编程（OOP）有基本了解，因为 Yii 是一个纯面向对象的框架。Yii 2.0 还使用了 PHP 的最新特性，例如 [命名空间](http://www.php.net/manual/en/language.namespaces.php) 和 [Trait（特质）](http://www.php.net/manual/en/language.oop5.traits.php)。理解这些概念将有助于你更快地掌握 Yii 2.0。
使用 Yii 需要对面向对象编程（OOP）有基本了解，因为 Yii 是一个纯面向对象的框架。Yii 2.0 还使用了 PHP 的最新特性，例如[命名空间](http://www.php.net/manual/en/language.namespaces.php)和[Trait（特质）](http://www.php.net/manual/en/language.oop5.traits.php)。理解这些概念将有助于你更快地掌握 Yii 2.0。
docs/guide-zh-CN/start-databases.md
使用数据库
======================
本章节将介绍如何如何创建一个从数据表 `country` 中获取国家数据并显示出来的页面。为了实现这个目标，你将会配置一个数据库连接，创建一个[活动记录](db-active-record.md)类，并且创建一个[操作](structure-controllers.md)及一个[视图](structure-views.md)。
本章节将介绍如何如何创建一个从数据表 `country` 中读取国家数据并显示出来的页面。为了实现这个目标，你将会配置一个数据库连接，创建一个[活动记录](db-active-record.md)类，并且创建一个[操作](structure-controllers.md)及一个[视图](structure-views.md)。
贯穿整个章节，你将会学到：
......@@ -16,7 +16,7 @@
准备数据库 <a name="preparing-database"></a>
--------------------
首先创建一个名为 `yii2basic` 的数据库，应用将从这个数据库中获取数据。你可以创建 SQLite，MySQL，PostregSQL，MSSQL 或 Oracle 数据库，Yii 内置多种数据库支持。简单起见后面的内容将以 MySQL 为例做演示。
首先创建一个名为 `yii2basic` 的数据库，应用将从这个数据库中读取数据。你可以创建 SQLite，MySQL，PostregSQL，MSSQL 或 Oracle 数据库，Yii 内置多种数据库支持。简单起见，后面的内容将以 MySQL 为例做演示。
然后在数据库中创建一个名为 `country` 的表并插入简单的数据。可以执行下面的语句：
......@@ -39,7 +39,7 @@ INSERT INTO `country` VALUES ('RU','Russia',146934000);
INSERT INTO `country` VALUES ('US','United States',278357000);
```
于是便有了一个名为 `yii2basic` 的数据库，在这个数据库中有一个包含三个字段的数据表 `country`，表中有十行数据。
此时便有了一个名为 `yii2basic` 的数据库，在这个数据库中有一个包含三个字段的数据表 `country`，表中有十行数据。
配置数据库连接 <a name="configuring-db-connection"></a>
---------------------------
......@@ -62,7 +62,7 @@ return [
`config/db/php` 是一个典型的基于文件的[配置](concept-configurations.md)工具。这个文件配置了数据库连接 [[yii\db\Connection]] 的创建和初始化参数，应用的 SQL 查询正是基于这个数据库。
上面配置的数据库连接可以在应用中通过 `Yii::$app->db` 访问。
上面配置的数据库连接可以在应用中通过 `Yii::$app->db` 表达式访问。
> 补充：`config/db.php` 将被包含在应用配置文件 `config/web.php` 中，后者指定了整个[应用](structure-applications.md)如何初始化。请参考[配置](concept-configurations.md)章节了解更多信息。
......@@ -70,7 +70,7 @@ return [
创建活动记录 <a name="creating-active-record"></a>
-------------------------
创建一个继承自[活动记录](db-active-record.md)类的类 `Country`，把它放在 `models/Country.php`，去表示和获取 `country` 表的数据。
创建一个继承自[活动记录](db-active-record.md)类的类 `Country`，把它放在 `models/Country.php` 文件，去代表和读取 `country` 表的数据。
```php
<?php
......@@ -86,7 +86,7 @@ class Country extends ActiveRecord
这个 `Country` 类继承自 [[yii\db\ActiveRecord]]。你不用在里面写任何代码。只需要像现在这样，Yii 就能根据类名去猜测对应的数据表名。
> 补充：如果类名和数据表名不能直接对应，可以重写 [[yii\db\ActiveRecord::tableName()|tableName()]] 方法去显式指定相关表名。
> 补充：如果类名和数据表名不能直接对应，可以覆写 [[yii\db\ActiveRecord::tableName()|tableName()]] 方法去显式指定相关表名。
使用 `Country` 类可以很容易地操作 `country` 表数据，就像这段代码：
......@@ -107,7 +107,7 @@ $country->name = 'U.S.A.';
$country->save();
```
> 补充：活动记录是面向对象、功能强大的访问和操作数据库数据的方式。你可以在[活动记录](db-active-record.md)章节了解更多信息。除此之外你还可以使用另一种更原生的称做[数据访问对象](db-dao)的方法操作数据库数据。
> 补充：活动记录是面向对象、功能强大的访问和操作数据库数据的方式。你可以在[活动记录](db-active-record.md)章节了解更多信息。除此之外你还可以使用另一种更原生的被称做[数据访问对象](db-dao)的方法操作数据库数据。
创建操作 <a name="creating-action"></a>
......@@ -148,7 +148,7 @@ class CountryController extends Controller
}
```
把上面的代码保存在 `controllers/CountryController.php`。
把上面的代码保存在 `controllers/CountryController.php` 文件中。
`index` 操作调用了活动记录 `Country::find()` 方法，去生成查询语句并从 `country` 表中取回所有数据。为了限定每个请求所返回的国家数量，查询在 [[yii\data\Pagination]] 对象的帮助下进行分页。 `Pagination` 对象的使命主要有两点：
......@@ -184,7 +184,7 @@ use yii\widgets\LinkPager;
这个视图包含两部分用以显示国家数据。第一部分遍历国家数据并以无序 HTML 列表渲染出来。第二部分使用 [[yii\widgets\LinkPager]] 去渲染从操作中传来的分页信息。小部件 `LinkPager` 显示一个分页按钮的列表。点击任何一个按钮都会跳转到对应的分页。
尝试下 <a name="trying-it-out"></a>
试运行 <a name="trying-it-out"></a>
-------------
浏览器访问下面的 URL 看看能否工作：
......
docs/guide-zh-CN/start-forms.md
使用表单
==================
本章节将介绍如何创建一个从用户那搜集数据的表单页。该页将显示一个包含 name 输入框和 email 输入框的表单。当搜集完这两部分信息后，页面将会显示用户输入的信息。
本章将介绍如何创建一个从用户那搜集数据的表单页。该页将显示一个包含 name 输入框和 email 输入框的表单。当搜集完这两部分信息后，页面将会显示用户输入的信息。
为了实现这个目标，除了创建一个[操作](structure-controllers.md)和两个[视图](structure-views)外，还需要创建一个[模型](structure-models.md)。
......@@ -39,11 +39,11 @@ class EntryForm extends Model
}
```
该类继承自 [[yii\base\Model]]，Yii 提供的一个基类，通常用来表示数据。
该类继承自 [[yii\base\Model]]，Yii 提供的一个基类，通常用来代表表单数据。
> 补充：[[yii\base\Model]] 被用于普通模型类的父类并与数据表**无关**。[[yii\db\ActiveRecord]] 通常是普通模型类的父类但与数据表有关联（译者注：[[yii\db\ActiveRecord]] 类其实也是继承自 [[yii\base\Model]]，增加了数据库处理）。
> 补充：[[yii\base\Model]] 被用于普通模型类的父类并与数据表**无关**。[[yii\db\ActiveRecord]] 通常是普通模型类的父类但与数据表有关联。
`EntryForm` 类包含 `name` 和 `email` 两个公共成员，用来储存用户输入的数据。它还包含一个名为 `rules()` 的方法，用来返回数据验证规则的集合。上面声明的验证规则表示：
`EntryForm` 类包含 `name` 和 `email` 两个公共变量，用来储存用户输入的数据。它还包含一个名为 `rules()` 的方法，用来返回数据验证规则的集合。上面声明的验证规则表示：
* `name` 和 `email` 值都是必须的
* `mail` 的值必须满足 email 地址验证
......@@ -67,7 +67,7 @@ if ($model->validate()) {
创建操作 <a name="creating-action"></a>
------------------
下面你得在 `site` 控制器中创建一个 `entry` 操作用于新建的模型。操作的创建和使用已经在[说一声你好](start-hello.md)小节中解释了。
接下来你需要在 `site` 控制器中创建一个 `entry` 操作用于新建的模型。操作的创建和使用已经在[说一声你好](start-hello.md)小节中解释了。
```php
<?php
......@@ -104,7 +104,7 @@ class SiteController extends Controller
> 补充：表达式 `Yii::$app` 代表[应用](structure-applications.md)实例，它是一个全局可访问的单例。同时它也是一个[服务定位器](concept-service-locator.md)，能提供 `request`，`response`，`db` 等等特定功能的组件。在上面的代码里就是使用 `request` 组件来访问应用实例收到的 `$_POST` 数据。
用户提交表单后，操作将会渲染一个名为 `entry-confirm` 的视图去确认用户输入的数据。如果没填表单就提交，或数据包含错误（译者：如 email 格式不对），`entry` 视图将会渲染输出，连同表单一起输出的还有验证错误的详细信息。
用户提交表单后，操作将会渲染一个名为 `entry-confirm` 的视图去确认用户输入的数据。如果没填表单就提交，或数据包含错误，`entry` 视图将会渲染输出，连同表单一起输出的还有验证错误的详细信息。
> 注意：在这个简单例子里我们只是呈现了有效数据的确认页面。实践中你应该考虑使用 [[yii\web\Controller::refresh()|refresh()]] 或 [[yii\web\Controller::redirect()|redirect()]] 去避免[表单重复提交问题](http://en.wikipedia.org/wiki/Post/Redirect/Get)。
......@@ -148,10 +148,10 @@ use yii\widgets\ActiveForm;
<?php ActiveForm::end(); ?>
```
视图使用了一个功能强大的[小部件](structure-widgets.md) [[yii\widgets\ActiveForm|ActiveForm]] 去生成 HTML 表单。其中的 `begin()` 和 `end()` 分别用来渲染表单的开始和关闭标签。在这两个方法之间使用了 [[yii\widgets\ActiveForm::field()|field()]] 方法去创建输入框。第一个输入框用于 “name”，第二个输入框用于 “email”。之后使用 [[yii\helpers\Html::submitButton()]] 方法生成提交按钮。
视图使用了一个功能强大的[小部件](structure-widgets.md) [[yii\widgets\ActiveForm|ActiveForm]] 去生成 HTML 表单。其中的 `begin()` 和 `end()` 分别用来渲染表单的开始和关闭标签。在这两个方法之间使用了 [[yii\widgets\ActiveForm::field()|field()]] 方法去创建表单栏。第一个表单栏用于 “name”，第二个表单栏用于 “email”。之后使用 [[yii\helpers\Html::submitButton()]] 方法生成提交按钮。
尝试下 <a name="trying-it-out"></a>
试运行 <a name="trying-it-out"></a>
-------------
用浏览器访问下面的 URL 看它能否工作：
......@@ -160,7 +160,7 @@ use yii\widgets\ActiveForm;
http://hostname/index.php?r=site/entry
```
你会看到一个包含两个输入框的表单的页面。每个输入框的前面都有一个标签指明应该输入的数据类型。如果什么都不填就点击提交按钮，或填入格式不正确的 email 地址，将会看到在对应的输入框下显示错误信息。
你会看到一个包含两个表单栏的页面。每个表单栏的前面都有一个标签指明应该输入的数据类型。如果什么都不填就点击提交按钮，或填入格式不正确的 email 地址，将会看到在对应的表单栏下显示错误信息。
![验证错误的表单](images/start-form-validation.png)
......@@ -172,13 +172,13 @@ http://hostname/index.php?r=site/entry
### 效果说明 <a name="magic-explained"></a>
你可能会好奇 HTML 表单暗地里是如何工作的呢，看起来它可以为每个输入框显示文字标签，而当你没输入正确的信息时又不需要刷新页面就能给出错误提示，似乎有些神奇。
你可能会好奇 HTML 表单暗地里是如何工作的，看起来它可以为每个表单栏显示文字标签，而当你没输入正确的信息时又不需要刷新页面就能给出错误提示，似乎有些神奇。
是的，其实数据首先由客户端 JavaScript 脚本验证，然后才会提交给服务器通过 PHP 验证。[[yii\widgets\ActiveForm]] 足够智能到把你在 `EntryForm` 模型中声明的验证规则转化成客户端 JavaScript 脚本去执行验证。如果用户浏览器禁用了 JavaScript， 服务器端仍然会像 `actionEntry()` 方法里这样验证一遍数据。这保证了任何情况下用户提交的数据都是有效的。
> 警告：客户端验证是提高用户体验的手段。无论它是否正常启用，服务端验证则都是必须的，请不要忽略它。
> 警告：客户端验证只是提高用户体验的手段。无论它是否正常启用，服务端验证则都是必须的，请不要忽略它。
输入框的文字标签是 `field()` 方法生成的，内容就是模型中该数据的属性名。例如模型中的 `name` 属性生成的标签就是 `Name`。
表单栏的文字标签是 `field()` 方法生成的，内容就是模型中该数据的属性名。例如模型中的 `name` 属性生成的标签就是 `Name`。
你可以在视图中自定义标签：
......@@ -193,7 +193,7 @@ http://hostname/index.php?r=site/entry
总结 <a name="summary"></a>
-------
本章节指南中你接触了 MVC 设计模式的每个部分。学到了如何创建一个模型代表用户数据并验证它的有效性。
本章指南中你接触了 MVC 设计模式的每个部分。学到了如何创建一个模型代表用户数据并验证它的有效性。
你还学到了如何从用户那获取数据并在浏览器上回显给用户。这本来是开发应用的过程中比较耗时的任务，好在 Yii 提供了强大的小部件让它变得如此简单。
......
docs/guide-zh-CN/start-gii.md
使用 Gii 生成代码
========================
本章节将介绍如何使用 [Gii](tool-gii.md) 去自动生成 Web 站点常用功能的代码。使用 Gii 生成代码非常简单，只要按照 Gii 页面上的介绍输入正确的信息即可。
本章将介绍如何使用 [Gii](tool-gii.md) 去自动生成 Web 站点常用功能的代码。使用 Gii 生成代码非常简单，只要按照 Gii 页面上的介绍输入正确的信息即可。
贯穿本章节，你将会学到：
......@@ -25,7 +25,7 @@ if (YII_ENV_DEV) {
}
```
这段配置的意思是如果当前是[开发环境](concept-configurations.md#environment-constants)，应用会包含 `gii` 模块，模块类是 [[yii\gii\Module]]。
这段配置表明，如果当前是[开发环境](concept-configurations.md#environment-constants)，应用会包含 `gii` 模块，模块类是 [[yii\gii\Module]]。
如果你检查应用的[入口脚本](structure-entry-scripts.md) `web/index.php`，将看到这行代码将 `YII_ENV_DEV` 设为 true：
......@@ -33,16 +33,18 @@ if (YII_ENV_DEV) {
defined('YII_ENV') or define('YII_ENV', 'dev');
```
代码设置应用处于开发模式下，按照上面的配置会打开 Gii 模块。你可以直接通过 URL 访问 Gii：
鉴于这行代码的定义，应用处于开发模式下，按照上面的配置会打开 Gii 模块。你可以直接通过 URL 访问 Gii：
```
http://hostname/index.php?r=gii
```
> 提示：如果不是通过localhost而是通过IP地址访问Gii，出于安全考虑系统默认禁止，按照如下在配置文件的gii部分添加允许IP地址访问。
> 补充： 如果你通过本机以外的机器访问 Gii，请求会被出于安全原因拒绝。你可以配置 Gii 为其添加允许访问的 IP 地址：
>
```php
'gii' => [
'class' => 'yii\gii\Module',
'allowedIPs' => ['127.0.0.1', '::1', '192.168.0.*', '192.168.178.20'] // 根据你自己的需要调整
'allowedIPs' => ['127.0.0.1', '::1', '192.168.0.*', '192.168.178.20'] // 按需调整这里
],
```
......@@ -61,7 +63,7 @@ http://hostname/index.php?r=gii
然后点击 “Preview” 按钮。你会看到 `models/Country.php` 被列在将要生成的文件列表中。可以点击文件名预览内容。
如果你已经创建过同样的文件，使用 Gii 可以覆写它，点击文件名旁边的 `diff` 能查看现有文件与将要生成的文件的内容区别。
如果你已经创建过同样的文件，使用 Gii 会覆写它，点击文件名旁边的 `diff` 能查看现有文件与将要生成的文件的内容区别。
![模型生成器预览](images/start-gii-model-preview.png)
......@@ -73,7 +75,7 @@ http://hostname/index.php?r=gii
生成 CRUD 代码 <a name="generating-crud"></a>
--------------------
CRUD 代表增，查，改，删操作，这是绝大多数 Web 站点常用的数据处理方式。选择 Gii 中的 “CRUD Generator” （点击 Gii 首页的链接）去创建 CRUD 功能。之前的 “country” 例子需要像这样填写表单：
CRUD 代表增，查，改，删操作，这是绝大多数 Web 站点常用的数据处理方式。选择 Gii 中的 “CRUD Generator” （点击 Gii 首页的链接）去创建 CRUD 功能。本例 “country” 中需要这样填写表单：
* Model Class: `app\models\Country`
* Search Model Class: `app\models\CountrySearch`
......@@ -83,12 +85,12 @@ CRUD 代表增，查，改，删操作，这是绝大多数 Web 站点常用的
然后点击 “Preview” 按钮。你会看到下述将要生成的文件列表。
![CRUD 生成器预览](images/start-gii-crud-preview.png)
[[NEED THE IMAGE HERE / 等待官方补充图片]]
如果你之前创建过 `controllers/CountryController.php` 和 `views/country/index.php` 文件（在指南的使用数据库小节），选中 “overwrite” 下的复选框覆写它们（之前的文件没能全部支持 CRUD）。
如果你之前创建过 `controllers/CountryController.php` 和 `views/country/index.php` 文件（在指南的使用数据库章节），选中 “overwrite” 下的复选框覆写它们（之前的文件没能全部支持 CRUD）。
尝试下<a name="trying-it-out"></a>
试运行 <a name="trying-it-out"></a>
-------------
用浏览器访问下面的 URL 查看生成代码的运行：
......@@ -97,7 +99,7 @@ CRUD 代表增，查，改，删操作，这是绝大多数 Web 站点常用的
http://hostname/index.php?r=country/index
```
可以看到一个栅格显示着从数据表中获取的国家数据。支持在列头对数据进行排序，输入筛选条件进行筛选。
可以看到一个栅格显示着从数据表中读取的国家数据。支持在列头对数据进行排序，输入筛选条件进行筛选。
可以浏览详情，编辑，或删除栅格中的每个国家。还可以点击栅格上方的 “Create Country” 按钮通过表单创建新国家。
......@@ -111,7 +113,7 @@ http://hostname/index.php?r=country/index
* 模型：`models/Country.php` 和 `models/CountrySearch.php`
* 视图：`views/country/*.php`
> 补充：Gii 被设计成高度可定制和可扩展的代码生成工具。使用它可以大幅提高应用开发速度。请参考 [Gii](tool-gii.md) 小节了解更多内容。
> 补充：Gii 被设计成高度可定制和可扩展的代码生成工具。使用它可以大幅提高应用开发速度。请参考 [Gii](tool-gii.md) 章节了解更多内容。
总结 <a name="summary"></a>
......
docs/guide-zh-CN/start-hello.md
说声 Hello
============
本章节描述了如何在你的应用中创建一个新的 “Hello” 页面。为了做到这点，将会创建一个[操作](structure-controllers.md#creating-actions)和一个[视图](structure-views.md)：
本章描述了如何在你的应用中创建一个新的 “Hello” 页面。为了实现这一目标，将会创建一个[操作](structure-controllers.md#creating-actions)和一个[视图](structure-views.md)：
* 应用将会分派页面请求给操作
* 操作将会依次渲染视图呈现 “Hello” 给最终用户
......@@ -16,7 +16,7 @@
创建操作 <a name="creating-action"></a>
------------------
为了说 “Hello”，需要创建一个 `say` [操作](structure-controllers.md#creating-actions)，从请求中接收 `message` 参数并显示给最终用户。如果请求没有提供 `message` 参数，操作将显示默认参数 “Hello”。
为了 “Hello”，需要创建一个 `say` [操作](structure-controllers.md#creating-actions)，从请求中接收 `message` 参数并显示给最终用户。如果请求没有提供 `message` 参数，操作将显示默认参数 “Hello”。
> 补充：[操作](structure-controllers.md#creating-actions)是最终用户可以直接访问并执行的对象。操作被组织在[控制器](structure-controllers.md)中。一个操作的执行结果就是最终用户收到的响应内容。
......@@ -33,7 +33,7 @@ class SiteController extends Controller
{
// ...其它代码...
public function actionSay($message = '你好')
public function actionSay($message = 'Hello')
{
return $this->render('say', ['message' => $message]);
}
......@@ -68,7 +68,7 @@ use yii\helpers\Html;
当然了，你大概会在 `say` 视图里放入更多内容。内容可以由 HTML 标签，纯文本，甚至 PHP 语句组成。实际上 `say` 视图就是一个由 [[yii\web\Controller::render()|render()]] 执行的 PHP 脚本。视图脚本输出的内容将会作为响应结果返回给应用。应用将依次输出结果给最终用户。
尝试下 <a name="trying-it-out"></a>
试运行 <a name="trying-it-out"></a>
-------------
创建完操作和视图后，你就可以通过下面的 URL 访问新页面了：
......
docs/guide-zh-CN/start-installation.md
......@@ -90,9 +90,9 @@ http://localhost/basic/web/index.php
>补充：如果你现在只是要试用 Yii 而不是将其部署到生产环境中，本小节可以跳过。
通过上述方法安装的应用程序在 Windows，Max OS X，Linux 中的 [Apache HTTP 服务器](http://httpd.apache.org/)或 [Nginx HTTP 服务器](http://nginx.org/) 且PHP版本为5.4或更高都可以直接运行。Yii 2.0 也兼容 Facebook 公司的 [HHVM](http://hhvm.com/)，由于 HHVM 和标准 PHP 在边界案例上有些地方略有不同，在使用 HHVM 时需稍作处理。
通过上述方法安装的应用程序在 Windows，Max OS X，Linux 中的 [Apache HTTP 服务器](http://httpd.apache.org/)或 [Nginx HTTP 服务器](http://nginx.org/)且PHP版本为5.4或更高都可以直接运行。Yii 2.0 也兼容 Facebook 公司的 [HHVM](http://hhvm.com/)，由于 HHVM 和标准 PHP 在边界案例上有些地方略有不同，在使用 HHVM 时需稍作处理。
在生产环境的服务器上，你可能会想配置服务器让应用程序可以通过 URL `http://www.example.com/index.php` 访问而不是 `http://www.example.com/basic/web/index.php`。这种配置需要将 Web 服务器的文档根目录指向 `basic/web` 目录。可能你还会想隐藏掉 URL 中的 `index.php`，具体细节在 [URL 解析和生成](runtime-url-handling.md) 一章中有介绍，你将学到如何配置 Apache 或 Nginx 服务器实现这些目标。
在生产环境的服务器上，你可能会想配置服务器让应用程序可以通过 URL `http://www.example.com/index.php` 访问而不是 `http://www.example.com/basic/web/index.php`。这种配置需要将 Web 服务器的文档根目录指向 `basic/web` 目录。可能你还会想隐藏掉 URL 中的 `index.php`，具体细节在 [URL 解析和生成](runtime-url-handling.md)一章中有介绍，你将学到如何配置 Apache 或 Nginx 服务器实现这些目标。
>补充：将 `basic/web` 设置为文档根目录，可以防止终端用户访问 `basic/web` 相邻目录中的私有应用代码和敏感数据文件。禁止对其他目录的访问是一个不错的安全改进。
......@@ -141,7 +141,7 @@ server {
error_log /path/to/basic/log/error.log;
location / {
# 如果找不到真实存在的文件，把请求重定向给 index.php
# 如果找不到真实存在的文件，把请求分发至 index.php
try_files $uri $uri/ /index.php?$args;
}
......
docs/guide-zh-CN/start-looking-ahead.md
更上一层楼
=============
通篇阅读完整个“入门”板块，你就完成了一个完整 Yii 应用的创建。在此过程中你学到了如何实现一些常用功能，例如通过 HTML 表单从用户那获取数据，从数据库中获取数据并以分页形式显示。你还学到了如何通过 [Gii](tool-gii.md) 去自动生成代码。使用 Gii 生成代码把 Web 开发中多数繁杂的过程转化为仅仅填写几个表单就行。
通篇阅读完整个“入门”部分，你就完成了一个完整 Yii 应用的创建。在此过程中你学到了如何实现一些常用功能，例如通过 HTML 表单从用户那获取数据，从数据库中获取数据并以分页形式显示。你还学到了如何通过 [Gii](tool-gii.md) 去自动生成代码。使用 Gii 生成代码把 Web 开发中多数繁杂的过程转化为仅仅填写几个表单就行。
本章节将介绍一些有助于更好使用 Yii 的资源：
本章将介绍一些有助于更好使用 Yii 的资源：
* 文档
- 权威指南：
顾名思义，指南详细描述了 Yii 的工作原理并提供了如何使用它的常规引导。这是最重要的 Yii 辅助资料，强烈建议在开始写 Yii 代码之前阅读。
- 类参考手册：
描述了 Yii 中每个类的用法。在编码过程中这极为有用，能够帮你理清某个特定类，方法，和属性的用法。类参考手册最好在整个框架的语境下去理解。
- Wiki 文章：
Wiki 文章是 Yii 用户在其自身经验基础上分享出来的。大多数是使用教程或如何使用 Yii 解决特定问题。虽然这些文章质量可能并不如权威指南，但它们往往覆盖了更广泛的话题，并常常提供解决方案，所以它们也很有用。
- 权威指南：顾名思义，指南详细描述了 Yii 的工作原理并提供了如何使用它的常规引导。这是最重要的 Yii 辅助资料，强烈建议在开始写 Yii 代码之前阅读。
- 类参考手册：描述了 Yii 中每个类的用法。在编码过程中这极为有用，能够帮你理清某个特定类，方法，和属性的用法。类参考手册最好在整个框架的语境下去理解。
- Wiki 文章：Wiki 文章是 Yii 用户在其自身经验基础上分享出来的。大多数是使用教程或如何使用 Yii 解决特定问题。虽然这些文章质量可能并不如权威指南，但它们往往覆盖了更广泛的话题，并常常提供解决方案，所以它们也很有用。
- 书籍
* [扩展](http://www.yiiframework.com/extensions/):
Yii 拥有数以千计用户提供的扩展，这些扩展能非常方便的插入到应用中，使你的应用开发过程更加方便快捷。
* [扩展](http://www.yiiframework.com/extensions/):Yii 拥有数以千计用户提供的扩展，这些扩展能非常方便的插入到应用中，使你的应用开发过程更加方便快捷。
* 社区
- [官方论坛](http://www.yiiframework.com/forum/)
- [GitHub](https://github.com/yiisoft/yii2)
......
docs/guide-zh-CN/structure-application-components.md 0 → 100644
应用组件
======================
应用主体是[服务定位器](concept-service-locator.md)，它部署一组提供各种不同功能的 *应用组件* 来处理请求。
例如，`urlManager`组件负责处理网页请求路由到对应的控制器。`db`组件提供数据库相关服务等等。
在同一个应用中，每个应用组件都有一个独一无二的 ID 用来区分其他应用组件，你可以通过如下表达式访问应用组件。
```php
\Yii::$app->componentID
```
例如，可以使用 `\Yii::$app->db` 来获取到已注册到应用的 [[yii\db\Connection|DB connection]]，
使用 `\Yii::$app->cache` 来获取到已注册到应用的 [[yii\caching\Cache|primary cache]]。
第一次使用以上表达式时候会创建应用组件实例，后续再访问会返回此实例，无需再次创建。
应用组件可以是任意对象，可以在 [应用主体配置](structure-applications.md#application-configurations)配置 [[yii\base\Application::components]] 属性 .
例如：
```php
[
'components' => [
// 使用类名注册 "cache" 组件
'cache' => 'yii\caching\ApcCache',
// 使用配置数组注册 "db" 组件
'db' => [
'class' => 'yii\db\Connection',
'dsn' => 'mysql:host=localhost;dbname=demo',
'username' => 'root',
'password' => '',
],
// 使用函数注册"search" 组件
'search' => function () {
return new app\components\SolrService;
},
],
]
```
> 补充：请谨慎注册太多应用组件，应用组件就像全局变量，使用太多可能加大测试和维护的难度。
一般情况下可以在需要时再创建本地组件。
## 引导启动组件 <a name="bootstrapping-components"></a>
上面提到一个应用组件只会在第一次访问时实例化，如果处理请求过程没有访问的话就不实例化。
有时你想在每个请求处理过程都实例化某个组件即便它不会被访问，
可以将该组件ID加入到应用主体的 [[yii\base\Application::bootstrap|bootstrap]] 属性中。
例如, 如下的应用主体配置保证了 `log` 组件一直被加载。
```php
[
'bootstrap' => [
// 将 log 组件 ID 加入引导让它始终载入
'log',
],
'components' => [
'log' => [
// "log" 组件的配置
],
],
]
```
## 核心应用组件 <a name="core-application-components"></a>
Yii 定义了一组固定ID和默认配置的 *核心* 组件，例如 [[yii\web\Application::request|request]] 组件
用来收集用户请求并解析 [路由](runtime-routing.md)；
[[yii\base\Application::db|db]] 代表一个可以执行数据库操作的数据库连接。
通过这些组件，Yii应用主体能处理用户请求。
下面是预定义的核心应用组件列表，可以和普通应用组件一样配置和自定义它们。
当你配置一个核心组件，不指定它的类名的话就会使用Yii默认指定的类。
* [[yii\web\AssetManager|assetManager]]: 管理资源包和资源发布，详情请参考 [管理资源](output-assets.md) 一节。
* [[yii\db\Connection|db]]: 代表一个可以执行数据库操作的数据库连接，
注意配置该组件时必须指定组件类名和其他相关组件属性，如[[yii\db\Connection::dsn]]。
详情请参考 [数据访问对象](db-dao.md) 一节。
* [[yii\base\Application::errorHandler|errorHandler]]: 处理 PHP 错误和异常，
详情请参考 [错误处理](tutorial-handling-errors.md) 一节。
* [[yii\i18n\Formatter|formatter]]: 格式化输出显示给终端用户的数据，例如数字可能要带分隔符，
日期使用长格式。详情请参考 [格式化输出数据](output-formatting.md) 一节。
* [[yii\i18n\I18N|i18n]]: 支持信息翻译和格式化。详情请参考 [国际化](tutorial-i18n.md) 一节。
* [[yii\log\Dispatcher|log]]: 管理日志对象。详情请参考 [日志](tutorial-logging.md) 一节。
* [[yii\swiftmailer\Mailer|mail]]: 支持生成邮件结构并发送，详情请参考 [邮件](tutorial-mailing.md) 一节。
* [[yii\base\Application::response|response]]: 代表发送给用户的响应，
详情请参考 [响应](runtime-responses.md) 一节。
* [[yii\base\Application::request|request]]: 代表从终端用户处接收到的请求，
详情请参考 [请求](runtime-requests.md) 一节。
* [[yii\web\Session|session]]: 代表会话信息，仅在[[yii\web\Application|Web applications]] 网页应用中可用，
详情请参考 [Sessions (会话) and Cookies](runtime-sessions-cookies.md) 一节。
* [[yii\web\UrlManager|urlManager]]: 支持URL地址解析和创建，
详情请参考 [URL 解析和生成](runtime-url-handling.md) 一节。
* [[yii\web\User|user]]: 代表认证登录用户信息，仅在[[yii\web\Application|Web applications]] 网页应用中可用，
详情请参考 [认证](security-authentication.md) 一节。
* [[yii\web\View|view]]: 支持渲染视图，详情请参考 [Views](structure-views.md) 一节。
docs/guide-zh-CN/structure-applications.md 0 → 100644
应用主体
============
应用主体是管理 Yii 应用系统整体结构和生命周期的对象。
每个Yii应用系统只能包含一个应用主体，应用主体在 [入口脚本](structure-entry-scripts.md) 中创建并能通过表达式 `\Yii::$app` 全局范围内访问。
> 补充: 当我们说"一个应用"，它可能是一个应用主体对象，也可能是一个应用系统，是根据上下文来决定[译：中文为避免歧义，Application翻译为应用主体]。
Yii有两种应用主体: [[yii\web\Application|网页应用主体]] and
[[yii\console\Application|控制台应用主体]]， 如名称所示，前者主要处理网页请求，后者处理控制台请求。
## 应用主体配置 <a name="application-configurations"></a>
如下所示，当 [入口脚本](structure-entry-scripts.md) 创建了一个应用主体，它会加载一个 [配置](concept-configurations.md) 文件并传给应用主体。
```php
require(__DIR__ . '/../vendor/autoload.php');
require(__DIR__ . '/../vendor/yiisoft/yii2/Yii.php');
// 加载应用主体配置
$config = require(__DIR__ . '/../config/web.php');
// 实例化应用主体、配置应用主体
(new yii\web\Application($config))->run();
```
类似其他 [配置](concept-configurations.md) 文件, 应用主体配置文件标明如何设置应用对象初始属性。
由于应用主体配置比较复杂，一般保存在多个类似如上web.php的 [配置文件](concept-configurations.md#configuration-files) 当中。
## 应用主体属性 <a name="application-properties"></a>
应用主体配置文件中有许多重要的属性要配置，这些属性指定应用主体的运行环境。
比如，应用主体需要知道如何加载 [控制器](structure-controllers.md) ，临时文件保存到哪儿等等。
以下我们简述这些属性。
### 必要属性 <a name="required-properties"></a>
在一个应用中，至少要配置2个属性: [[yii\base\Application::id|id]] 和 [[yii\base\Application::basePath|basePath]]。
#### [[yii\base\Application::id|id]] <a name="id"></a>
[[yii\base\Application::id|id]] 属性用来区分其他应用的唯一标识ID。主要给程序使用。
为了方便协作，最好使用数字作为应用主体ID，但不强制要求为数字。
#### [[yii\base\Application::basePath|basePath]] <a name="basePath"></a>
[[yii\base\Application::basePath|basePath]] 指定该应用的根目录。根目录包含应用系统所有受保护的源代码。
在根目录下可以看到对应MVC设计模式的`models`, `views`, `controllers`等子目录。
可以使用路径或 [路径别名](concept-aliases.md) 来在配置 [[yii\base\Application::basePath|basePath]] 属性。
两种格式所对应的目录都必须存在，否则系统会抛出一个异常。 系统会使用 `realpath()` 函数规范化配置的路径.
[[yii\base\Application::basePath|basePath]] 属性经常用于派生一些其他重要路径（如runtime路径），因此，系统预定义 `@app` 代表这个路径。
派生路径可以通过这个别名组成（如`@app/runtime`代表runtime的路径）。
### 重要属性 <a name="important-properties"></a>
本小节所描述的属性通常需要设置，因为不用的应用属性不同。
#### [[yii\base\Application::aliases|aliases]] <a name="aliases"></a>
该属性允许你用一个数组定义多个 [别名](concept-aliases.md)。数组的key为别名名称，值为对应的路径。例如：
```php
[
'aliases' => [
'@name1' => 'path/to/path1',
'@name2' => 'path/to/path2',
],
]
```
使用这个属性来定义别名，代替 [[Yii::setAlias()]] 方法来设置。
#### [[yii\base\Application::bootstrap|bootstrap]] <a name="bootstrap"></a>
这个属性很实用，它允许你用数组指定启动阶段[[yii\base\Application::bootstrap()|bootstrapping process]]需要运行的组件。
比如，如果你希望一个 [模块](structure-modules.md) 自定义 [URL 规则](runtime-url-handling.md)，你可以将模块ID加入到bootstrap数组中。
属性中的每个组件需要指定以下一项:
- 应用 [组件](#components) ID.
- [模块](#modules) ID.
- 类名.
- 配置数组.
- 创建并返回一个组件的无名称函数.
例如：
```php
[
'bootstrap' => [
// 应用组件ID或模块ID
'demo',
// 类名
'app\components\Profiler',
// 配置数组
[
'class' => 'app\components\Profiler',
'level' => 3,
],
// 无名称函数
function () {
return new app\components\Profiler();
}
],
]
```
> 补充: 如果模块ID和应用组件ID同名，优先使用应用组件ID，如果你想用模块ID，可以使用如下无名称函数返回模块ID。
>```php
[
function () {
return Yii::$app->getModule('user');
},
]
```
在启动阶段，每个组件都会实例化。如果组件类实现接口 [[yii\base\BootstrapInterface]],也会调用 [[yii\base\BootstrapInterface::bootstrap()|bootstrap()]] 方法。
举一个实际的例子，[Basic Application Template](start-installation.md) 应用主体配置中，
开发环境下会在启动阶段运行 `debug` 和 `gii` 模块。
```php
if (YII_ENV_DEV) {
// configuration adjustments for 'dev' environment
$config['bootstrap'][] = 'debug';
$config['modules']['debug'] = 'yii\debug\Module';
$config['bootstrap'][] = 'gii';
$config['modules']['gii'] = 'yii\gii\Module';
}
```
> 注: 启动太多的组件会降低系统性能，因为每次请求都需要重新运行启动组件，因此谨慎配置启动组件。
#### [[yii\web\Application::catchAll|catchAll]] <a name="catchAll"></a>
该属性仅 [[yii\web\Application|Web applications]] 网页应用支持。
它指定一个要处理所有用户请求的 [控制器方法](structure-controllers.md)，通常在维护模式下使用，同一个方法处理所有用户请求。
该配置为一个数组，第一项指定动作的路由，剩下的数组项(key-value 成对)指定传递给动作的参数，例如：
```php
[
'catchAll' => [
'offline/notice',
'param1' => 'value1',
'param2' => 'value2',
],
]
```
#### [[yii\base\Application::components|components]] <a name="components"></a>
这是最重要的属性，它允许你注册多个在其他地方使用的[应用组件](#structure-application-components.md). 例如
```php
[
'components' => [
'cache' => [
'class' => 'yii\caching\FileCache',
],
'user' => [
'identityClass' => 'app\models\User',
'enableAutoLogin' => true,
],
],
]
```
每一个应用组件指定一个key-value对的数组，key代表组件ID，value代表组件类名或 [配置](concept-configurations.md)。
在应用中可以任意注册组件，并可以通过表达式 `\Yii::$app->ComponentID` 全局访问。
详情请阅读 [应用组件](structure-application-components.md) 一节.
#### [[yii\base\Application::controllerMap|controllerMap]] <a name="controllerMap"></a>
该属性允许你指定一个控制器ID到任意控制器类。Yii遵循一个默认的 [规则](#controllerNamespace)指定控制器ID到任意控制器类（如`post`对应`app\controllers\PostController`）。
通过配置这个属性，可以打破这个默认规则，在下面的例子中，`account`对应到`app\controllers\UserController`，
`article` 对应到 `app\controllers\PostController`。
```php
[
'controllerMap' => [
[
'account' => 'app\controllers\UserController',
'article' => [
'class' => 'app\controllers\PostController',
'enableCsrfValidation' => false,
],
],
],
]
```
数组的键代表控制器ID，数组的值代表对应的类名。
#### [[yii\base\Application::controllerNamespace|controllerNamespace]] <a name="controllerNamespace"></a>
该属性指定控制器类默认的命名空间，默认为`app\controllers`。比如控制器ID为 `post` 默认对应 `PostController` （不带命名空间），
类全名为 `app\controllers\PostController`。
控制器类文件可能放在这个命名空间对应目录的子目录下，
例如，控制器ID `admin/post` 对应的控制器类全名为 `app\controllers\admin\PostController`。
控制器类全面能被 [自动加载](concept-autoloading.md)，这点是非常重要的，控制器类的实际命名空间对应这个属性，
否则，访问时你会收到"Page Not Found"[译：页面找不到]。
如果你想打破上述的规则，可以配置 [controllerMap](#controllerMap) 属性。
#### [[yii\base\Application::language|language]] <a name="language"></a>
该属性指定应用展示给终端用户的语言，默认为 `en` 标识英文。如果需要之前其他语言可以配置该属性。
该属性影响各种 [国际化](tutorial-i18n.md) ，包括信息翻译、日期格式、数字格式等。
例如 [[yii\jui\DatePicker]] 小部件会根据该属性展示对应语言的日历以及日期格式。
推荐遵循 [IETF language tag](http://en.wikipedia.org/wiki/IETF_language_tag) 来设置语言，例如 `en` 代表英文， `en-US` 代表英文(美国).
该属性的更多信息可参考 [国际化](tutorial-i18n.md) 一节.
#### [[yii\base\Application::modules|modules]] <a name="modules"></a>
该属性指定应用所包含的 [模块](structure-modules.md)。
该属性使用数组包含多个模块类 [配置](concept-configurations.md)，数组的键为模块ID，例：
```php
[
'modules' => [
// "booking" 模块以及对应的类
'booking' => 'app\modules\booking\BookingModule',
// "comment" 模块以及对应的配置数组
'comment' => [
'class' => 'app\modules\comment\CommentModule',
'db' => 'db',
],
],
]
```
更多详情请参考 [模块](structure-modules.md) 一节。
#### [[yii\base\Application::name|name]] <a name="name"></a>
该属性指定你可能想展示给终端用户的应用名称，不同于需要唯一性的 [[yii\base\Application::id|id]] 属性，
该属性可以不唯一，该属性用于显示应用的用途。
如果其他地方的代码没有用到，可以不配置该属性。
#### [[yii\base\Application::params|params]] <a name="params"></a>
该属性为一个数组，指定可以全局访问的参数，代替程序中硬编码的数字和字符，应用中的参数定义到一个单独的文件并随时可以访问是一个好习惯。
例如用参数定义缩略图的长宽如下：
```php
[
'params' => [
'thumbnail.size' => [128, 128],
],
]
```
然后简单的使用如下代码即可获取到你需要的长宽参数：
```php
$size = \Yii::$app->params['thumbnail.size'];
$width = \Yii::$app->params['thumbnail.size'][0];
```
以后想修改缩略图长宽，只需要修改该参数而不需要相关的代码。
#### [[yii\base\Application::sourceLanguage|sourceLanguage]] <a name="sourceLanguage"></a>
该属性指定应用代码的语言，默认为 `'en-US'` 标识英文（美国），如果应用不是英文请修改该属性。
和 [语言](#language) 属性类似，配置该属性需遵循 [IETF language tag](http://en.wikipedia.org/wiki/IETF_language_tag).
例如 `en` 代表英文， `en-US` 代表英文(美国)。
该属性的更多信息可参考 [国际化](tutorial-i18n.md) 一节.
#### [[yii\base\Application::timeZone|timeZone]] <a name="timeZone"></a>
该属性提供一种方式修改PHP运行环境中的默认时区，配置该属性本质上就是调用PHP函数
[date_default_timezone_set()](http://php.net/manual/en/function.date-default-timezone-set.php)，例如：
```php
[
'timeZone' => 'America/Los_Angeles',
]
```
#### [[yii\base\Application::version|version]] <a name="version"></a>
该属性指定应用的版本，默认为`'1.0'`，其他代码不使用的话可以不配置。
### 实用属性 <a name="useful-properties"></a>
本小节描述的属性不经常设置，通常使用系统默认值。如果你想改变默认值，可以配置这些属性。
#### [[yii\base\Application::charset|charset]] <a name="charset"></a>
该属性指定应用使用的字符集，默认值为 `'UTF-8'`，绝大部分应用都在使用，除非已有的系统大量使用非unicode数据才需要更改该属性。
#### [[yii\base\Application::defaultRoute|defaultRoute]] <a name="defaultRoute"></a>
该属性指定未配置的请求的响应 [路由](runtime-routing.md) 规则，路由规则可能包含模块ID，控制器ID，动作ID。
例如`help`, `post/create`, `admin/post/create`，如果动作ID没有指定，会使用[[yii\base\Controller::defaultAction]]中指定的默认值。
对于 [[yii\web\Application|Web applications]] 网页应用，默认值为 `'site'` 对应 `SiteController` 控制器，并使用默认的动作。
因此你不带路由的访问应用，默认会显示 `app\controllers\SiteController::actionIndex()` 的结果。
对于 [[yii\console\Application|console applications]] 控制台应用，
默认值为 `'help'` 对应 [[yii\console\controllers\HelpController::actionIndex()]]。
因此，如果执行的命令不带参数，默认会显示帮助信息。
#### [[yii\base\Application::extensions|extensions]] <a name="extensions"></a>
该属性用数组列表指定应用安装和使用的 [扩展](structure-extensions.md)，默认使用`@vendor/yiisoft/extensions.php`文件返回的数组。
当你使用 [Composer](http://getcomposer.org) 安装扩展，`extensions.php` 会被自动生成和维护更新。
所以大多数情况下，不需要配置该属性。
特殊情况下你想自己手动维护扩展，可以参照如下配置该属性：
```php
[
'extensions' => [
[
'name' => 'extension name',
'version' => 'version number',
'bootstrap' => 'BootstrapClassName', // 可选配，可为配置数组
'alias' => [ // 可选配
'@alias1' => 'to/path1',
'@alias2' => 'to/path2',
],
],
// ... 更多像上面的扩展 ...
],
]
```
如上所示，该属性包含一个扩展定义数组，每个扩展为一个包含 `name` 和 `version` 项的数组。
如果扩展要在 [引导启动](runtime-bootstrapping.md) 阶段运行，需要配置 `bootstrap`以及对应的引导启动类名或 [configuration](concept-configurations.md) 数组。
扩展也可以定义 [别名](concept-aliases.md)
#### [[yii\base\Application::layout|layout]] <a name="layout"></a>
该属性指定渲染 [视图](structure-views.md) 默认使用的布局名字，默认值为 `'main'` 对应[布局路径](#layoutPath)下的 `main.php` 文件，
如果 [布局路径](#layoutPath) 和 [视图路径](#viewPath) 都是默认值，默认布局文件可以使用路径别名`@app/views/layouts/main.php`
如果不想设置默认布局文件，可以设置该属性为 `false`，这种做法比较罕见。
#### [[yii\base\Application::layoutPath|layoutPath]] <a name="layoutPath"></a>
该属性指定查找布局文件的路径，默认值为 [视图路径](#viewPath) 下的 `layouts` 子目录。
如果 [视图路径](#viewPath) 使用默认值，默认的布局路径别名为`@app/views/layouts`。
该属性需要配置成一个目录或 路径 [别名](concept-aliases.md)。
You may configure it as a directory or a path [alias](concept-aliases.md).
#### [[yii\base\Application::runtimePath|runtimePath]] <a name="runtimePath"></a>
该属性指定临时文件如日志文件、缓存文件等保存路径，默认值为带别名的 `@app/runtime`。
可以配置该属性为一个目录或者路径 [别名](concept-aliases.md)，注意应用运行时有对该路径的写入权限，
以及终端用户不能访问改路径因为临时文件可能包含一些敏感信息。
为了简化访问该路径，Yii预定义别名 `@runtime` 代表该路径。
#### [[yii\base\Application::viewPath|viewPath]] <a name="viewPath"></a>
该路径指定视图文件的根目录，默认值为带别名的 `@app/views`，可以配置它为一个目录或者路径 [别名](concept-aliases.md).
#### [[yii\base\Application::vendorPath|vendorPath]] <a name="vendorPath"></a>
该属性指定 [Composer](http://getcomposer.org) 管理的供应商路径，该路径包含应用使用的包括Yii框架在内的所有第三方库。
默认值为带别名的 `@app/vendor` 。
可以配置它为一个目录或者路径 [别名](concept-aliases.md)，当你修改时，务必修改对应的 Composer 配置。
为了简化访问该路径，Yii预定义别名 `@vendor` 代表该路径。
#### [[yii\console\Application::enableCoreCommands|enableCoreCommands]] <a name="enableCoreCommands"></a>
该属性仅 [[yii\console\Application|console applications]] 控制台应用支持， 用来指定是否启用Yii中的核心命令，默认值为 `true`。
## 应用事件 <a name="application-events"></a>
应用在处理请求过程中会触发事件，可以在配置文件配置事件处理代码，如下所示：
```php
[
'on beforeRequest' => function ($event) {
// ...
},
]
```
`on eventName` 语法的用法在 [Configurations](concept-configurations.md#configuration-format) 一节有详细描述.
另外，在应用主体实例化后，你可以在[引导启动](runtime-bootstrapping.md) 阶段附加事件处理代码，例如：
```php
\Yii::$app->on(\yii\base\Application::EVENT_BEFORE_REQUEST, function ($event) {
// ...
});
```
### [[yii\base\Application::EVENT_BEFORE_REQUEST|EVENT_BEFORE_REQUEST]] <a name="beforeRequest"></a>
该事件在应用处理请求*before*之前，实际的事件名为 `beforeRequest`。
在事件触发前，应用主体已经实例化并配置好了，所以通过事件机制将你的代码嵌入到请求处理过程中非常不错。
例如在事件处理中根据某些参数动态设置[[yii\base\Application::language]]语言属性。
### [[yii\base\Application::EVENT_BEFORE_REQUEST|EVENT_AFTER_REQUEST]] <a name="afterRequest"></a>
该事件在应用处理请求*after*之后但在返回响应*before*之前触发，实际的事件名为`afterRequest`。
该事件触发时，请求已经被处理完，可以做一些请求后处理或自定义响应。
注意 [[yii\web\Response|response]] 组件在发送响应给终端用户时也会触发一些事件，这些事件都在本事件*after*之后触发。
### [[yii\base\Application::EVENT_BEFORE_REQUEST|EVENT_BEFORE_ACTION]] <a name="beforeAction"></a>
该事件在每个 [控制器动作](structure-controllers.md) 运行*before*之前会被触发，实际的事件名为 `beforeAction`.
事件的参数为一个 [[yii\base\ActionEvent]] 实例，
事件处理中可以设置[[yii\base\ActionEvent::isValid]] 为 `false` 停止运行后续动作，例如：
```php
[
'on beforeAction' => function ($event) {
if (some condition) {
$event->isValid = false;
} else {
}
},
]
```
注意 [模块](structure-modules.md) 和 [控制器](structure-controllers.md) 都会触发 `beforeAction` 事件。
应用主体对象首先触发该事件，然后模块触发（如果存在模块），最后控制器触发。
任何一个事件处理中设置 [[yii\base\ActionEvent::isValid]] 设置为 `false` 会停止触发后面的事件。
### [[yii\base\Application::EVENT_BEFORE_REQUEST|EVENT_AFTER_ACTION]] <a name="afterAction"></a>
该事件在每个 [控制器动作](structure-controllers.md) 运行*after*之后会被触发，实际的事件名为 `afterAction`.
该事件的参数为 [[yii\base\ActionEvent]] 实例，通过[[yii\base\ActionEvent::result]]属性，
事件处理可以访问和修改动作的结果。例如：
```php
[
'on afterAction' => function ($event) {
if (some condition) {
// 修改 $event->result
} else {
}
},
]
```
注意 [模块](structure-modules.md) 和 [控制器](structure-controllers.md) 都会触发 `afterAction` 事件。
这些对象的触发顺序和 `beforeAction` 相反，也就是说，控制器最先触发，然后是模块（如果有模块），最后为应用主体。
## 应用主体生命周期 <a name="application-lifecycle"></a>
当运行 [入口脚本](structure-entry-scripts.md) 处理请求时，应用主体会经历以下生命周期:
1. 入口脚本加载应用主体配置数组。
2. 入口脚本创建一个应用主体实例：
* 调用 [[yii\base\Application::preInit()|preInit()]] 配置几个高级别应用主体属性，比如[[yii\base\Application::basePath|basePath]]。
* 注册 [[yii\base\Application::errorHandler|error handler]] 错误处理方法.
* 配置应用主体属性.
* 调用 [[yii\base\Application::init()|init()]] 初始化，该函数会调用 [[yii\base\Application::bootstrap()|bootstrap()]] 运行引导启动组件.
3. 入口脚本调用 [[yii\base\Application::run()]] 运行应用主体:
* 触发 [[yii\base\Application::EVENT_BEFORE_REQUEST|EVENT_BEFORE_REQUEST]] 事件。
* 处理请求：解析请求 [路由](runtime-routing.md) 和相关参数；创建路由指定的模块、控制器和动作对应的类，并运行动作。
* 触发 [[yii\base\Application::EVENT_AFTER_REQUEST|EVENT_AFTER_REQUEST]] 事件。
* 发送响应到终端用户.
4. 入口脚本接收应用主体传来的退出状态并完成请求的处理。
docs/guide-zh-CN/structure-controllers.md 0 → 100644
Controllers
===========
Controllers are part of the [MVC](http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller) architecture.
They are objects of classes extending from [[yii\base\Controller]] and are responsible for processing requests and
generating responses. In particular, after taking over the control from [applications](structure-applications.md),
controllers will analyze incoming request data, pass them to [models](structure-models.md), inject model results
into [views](structure-views.md), and finally generate outgoing responses.
## Actions <a name="actions"></a>
Controllers are composed by *actions* which are the most basic units that end users can address and request for
execution. A controller can have one or multiple actions.
The following example shows a `post` controller with two actions: `view` and `create`:
```php
namespace app\controllers;
use Yii;
use app\models\Post;
use yii\web\Controller;
use yii\web\NotFoundHttpException;
class PostController extends Controller
{
public function actionView($id)
{
$model = Post::findOne($id);
if ($model === null) {
throw new NotFoundHttpException;
}
return $this->render('view', [
'model' => $model,
]);
}
public function actionCreate()
{
$model = new Post;
if ($model->load(Yii::$app->request->post()) && $model->save()) {
return $this->redirect(['view', 'id' => $model->id]);
} else {
return $this->render('create', [
'model' => $model,
]);
}
}
}
```
In the `view` action (defined by the `actionView()` method), the code first loads the [model](structure-models.md)
according to the requested model ID; If the model is loaded successfully, it will display it using
a [view](structure-views.md) named `view`. Otherwise, it will throw an exception.
In the `create` action (defined by the `actionCreate()` method), the code is similar. It first tries to populate
the [model](structure-models.md) using the request data and save the model. If both succeed it will redirect
the browser to the `view` action with the ID of the newly created model. Otherwise it will display
the `create` view through which users can provide the needed input.
## Routes <a name="routes"></a>
End users address actions through the so-called *routes*. A route is a string that consists of the following parts:
* a module ID: this exists only if the controller belongs to a non-application [module](structure-modules.md);
* a controller ID: a string that uniquely identifies the controller among all controllers within the same application
(or the same module if the controller belongs to a module);
* an action ID: a string that uniquely identifies the action among all actions within the same controller.
Routes take the following format:
```
ControllerID/ActionID
```
or the following format if the controller belongs to a module:
```php
ModuleID/ControllerID/ActionID
```
So if a user requests with the URL `http://hostname/index.php?r=site/index`, the `index` action in the `site` controller
will be executed. For more details how routes are resolved into actions, please refer to
the [Routing](runtime-routing.md) section.
## Creating Controllers <a name="creating-controllers"></a>
In [[yii\web\Application|Web applications]], controllers should extend from [[yii\web\Controller]] or its
child classes. Similarly in [[yii\console\Application|console applications]], controllers should extend from
[[yii\console\Controller]] or its child classes. The following code defines a `site` controller:
```php
namespace app\controllers;
use yii\web\Controller;
class SiteController extends Controller
{
}
```
### Controller IDs <a name="controller-ids"></a>
Usually, a controller is designed to handle the requests regarding a particular type of resource.
For this reason, controller IDs are often nouns referring to the types of the resources that they are handling.
For example, you may use `article` as the ID of a controller that handles article data.
By default, controller IDs should contain these characters only: English letters in lower case, digits,
underscores, dashes and forward slashes. For example, `article` and `post-comment` are both valid controller IDs,
while `article?`, `PostComment`, `admin\post` are not.
A controller ID may also contain a subdirectory prefix. For example, `admin/article` stands for an `article` controller
in the `admin` subdirectory under the [[yii\base\Application::controllerNamespace|controller namespace]].
Valid characters for subdirectory prefixes include: English letters in lower and upper cases, digits, underscores and
forward slashes, where forward slashes are used as separators for multi-level subdirectories (e.g. `panels/admin`).
### Controller Class Naming <a name="controller-class-naming"></a>
Controller class names can be derived from controller IDs according to the following rules:
* Turn the first letter in each word separated by dashes into upper case. Note that if the controller ID
contains slashes, this rule only applies to the part after the last slash in the ID.
* Remove dashes and replace any forward slashes with backward slashes.
* Append the suffix `Controller`.
* And prepend the [[yii\base\Application::controllerNamespace|controller namespace]].
The followings are some examples, assuming the [[yii\base\Application::controllerNamespace|controller namespace]]
takes the default value `app\controllers`:
* `article` derives `app\controllers\ArticleController`;
* `post-comment` derives `app\controllers\PostCommentController`;
* `admin/post-comment` derives `app\controllers\admin\PostCommentController`;
* `adminPanels/post-comment` derives `app\controllers\adminPanels\PostCommentController`.
Controller classes must be [autoloadable](concept-autoloading.md). For this reason, in the above examples,
the `article` controller class should be saved in the file whose [alias](concept-aliases.md)
is `@app/controllers/ArticleController.php`; while the `admin/post2-comment` controller should be
in `@app/controllers/admin/Post2CommentController.php`.
> Info: The last example `admin/post2-comment` shows how you can put a controller under a sub-directory
of the [[yii\base\Application::controllerNamespace|controller namespace]]. This is useful when you want
to organize your controllers into several categories and you do not want to use [modules](structure-modules.md).
### Controller Map <a name="controller-map"></a>
You can configure [[yii\base\Application::controllerMap|controller map]] to overcome the constraints
of the controller IDs and class names described above. This is mainly useful when you are using some
third-party controllers which you do not control over their class names.
You may configure [[yii\base\Application::controllerMap|controller map]] in the
[application configuration](structure-applications.md#application-configurations) like the following:
```php
[
'controllerMap' => [
// declares "account" controller using a class name
'account' => 'app\controllers\UserController',
// declares "article" controller using a configuration array
'article' => [
'class' => 'app\controllers\PostController',
'enableCsrfValidation' => false,
],
],
]
```
### Default Controller <a name="default-controller"></a>
Each application has a default controller specified via the [[yii\base\Application::defaultRoute]] property.
When a request does not specify a [route](#ids-routes), the route specified by this property will be used.
For [[yii\web\Application|Web applications]], its value is `'site'`, while for [[yii\console\Application|console applications]],
it is `help`. Therefore, if a URL is `http://hostname/index.php`, it means the `site` controller will handle the request.
You may change the default controller with the following [application configuration](structure-applications.md#application-configurations):
```php
[
'defaultRoute' => 'main',
]
```
## Creating Actions <a name="creating-actions"></a>
Creating actions can be as simple as defining the so-called *action methods* in a controller class. An action method is
a *public* method whose name starts with the word `action`. The return value of an action method represents
the response data to be sent to end users. The following code defines two actions `index` and `hello-world`:
```php
namespace app\controllers;
use yii\web\Controller;
class SiteController extends Controller
{
public function actionIndex()
{
return $this->render('index');
}
public function actionHelloWorld()
{
return 'Hello World';
}
}
```
### Action IDs <a name="action-ids"></a>
An action is often designed to perform a particular manipulation about a resource. For this reason,
action IDs are usually verbs, such as `view`, `update`, etc.
By default, action IDs should contain these characters only: English letters in lower case, digits,
underscores and dashes. The dashes in an actionID are used to separate words. For example,
`view`, `update2`, `comment-post` are all valid action IDs, while `view?`, `Update` are not.
You can create actions in two ways: inline actions and standalone actions. An inline action is
defined as a method in the controller class, while a standalone action is a class extending
[[yii\base\Action]] or its child class. Inline actions take less effort to create and are often preferred
if you have no intention to reuse these actions. Standalone actions, on the other hand, are mainly
created to be used in different controllers or be redistributed as [extensions](structure-extensions.md).
### Inline Actions <a name="inline-actions"></a>
Inline actions refer to the actions that are defined in terms of action methods as we just described.
The names of the action methods are derived from action IDs according to the following criteria:
* Turn the first letter in each word of the action ID into upper case;
* Remove dashes;
* Prepend the prefix `action`.
For example, `index` becomes `actionIndex`, and `hello-world` becomes `actionHelloWorld`.
> Note: The names of the action methods are *case-sensitive*. If you have a method named `ActionIndex`,
it will not be considered as an action method, and as a result, the request for the `index` action
will result in an exception. Also note that action methods must be public. A private or protected
method does NOT define an inline action.
Inline actions are the most commonly defined actions because they take little effort to create. However,
if you plan to reuse the same action in different places, or if you want to redistribute an action,
you should consider defining it as a *standalone action*.
### Standalone Actions <a name="standalone-actions"></a>
Standalone actions are defined in terms of action classes extending [[yii\base\Action]] or its child classes.
For example, in the Yii releases, there are [[yii\web\ViewAction]] and [[yii\web\ErrorAction]], both of which
are standalone actions.
To use a standalone action, you should declare it in the *action map* by overriding the
[[yii\base\Controller::actions()]] method in your controller classes like the following:
```php
public function actions()
{
return [
// declares "error" action using a class name
'error' => 'yii\web\ErrorAction',
// declares "view" action using a configuration array
'view' => [
'class' => 'yii\web\ViewAction',
'viewPrefix' => '',
],
];
}
```
As you can see, the `actions()` method should return an array whose keys are action IDs and values the corresponding
action class names or [configurations](concept-configurations.md). Unlike inline actions, action IDs for standalone
actions can contain arbitrary characters, as long as they are declared in the `actions()` method.
To create a standalone action class, you should extend [[yii\base\Action]] or its child class, and implement
a public method named `run()`. The role of the `run()` method is similar to that of an action method. For example,
```php
<?php
namespace app\components;
use yii\base\Action;
class HelloWorldAction extends Action
{
public function run()
{
return "Hello World";
}
}
```
### Action Results <a name="action-results"></a>
The return value of an action method or the `run()` method of a standalone action is significant. It stands
for the result of the corresponding action.
The return value can be a [response](runtime-responses.md) object which will be sent to as the response
to end users.
* For [[yii\web\Application|Web applications]], the return value can also be some arbitrary data which will
be assigned to [[yii\web\Response::data]] and be further converted into a string representing the response body.
* For [[yii\console\Application|console applications]], the return value can also be an integer representing
the [[yii\console\Response::exitStatus|exit status]] of the command execution.
In the examples shown above, the action results are all strings which will be treated as the response body
to be sent to end users. The following example shows how an action can redirect the user browser to a new URL
by returning a response object (because the [[yii\web\Controller::redirect()|redirect()]] method returns
a response object):
```php
public function actionForward()
{
// redirect the user browser to http://example.com
return $this->redirect('http://example.com');
}
```
### Action Parameters <a name="action-parameters"></a>
The action methods for inline actions and the `run()` methods for standalone actions can take parameters,
called *action parameters*. Their values are obtained from requests. For [[yii\web\Application|Web applications]],
the value of each action parameter is retrieved from `$_GET` using the parameter name as the key;
for [[yii\console\Application|console applications]], they correspond to the command line arguments.
In the following example, the `view` action (an inline action) has declared two parameters: `$id` and `$version`.
```php
namespace app\controllers;
use yii\web\Controller;
class PostController extends Controller
{
public function actionView($id, $version = null)
{
// ...
}
}
```
The action parameters will be populated as follows for different requests:
* `http://hostname/index.php?r=post/view&id=123`: the `$id` parameter will be filled with the value
`'123'`, while `$version` is still null because there is no `version` query parameter.
* `http://hostname/index.php?r=post/view&id=123&version=2`: the `$id` and `$version` parameters will
be filled with `'123'` and `'2'`, respectively.
* `http://hostname/index.php?r=post/view`: a [[yii\web\BadRequestHttpException]] exception will be thrown
because the required `$id` parameter is not provided in the request.
* `http://hostname/index.php?r=post/view&id[]=123`: a [[yii\web\BadRequestHttpException]] exception will be thrown
because `$id` parameter is receiving an unexpected array value `['123']`.
If you want an action parameter to accept array values, you should type-hint it with `array`, like the following:
```php
public function actionView(array $id, $version = null)
{
// ...
}
```
Now if the request is `http://hostname/index.php?r=post/view&id[]=123`, the `$id` parameter will take the value
of `['123']`. If the request is `http://hostname/index.php?r=post/view&id=123`, the `$id` parameter will still
receive the same array value because the scalar value `'123'` will be automatically turned into an array.
The above examples mainly show how action parameters work for Web applications. For console applications,
please refer to the [Console Commands](tutorial-console.md) section for more details.
### Default Action <a name="default-action"></a>
Each controller has a default action specified via the [[yii\base\Controller::defaultAction]] property.
When a [route](#ids-routes) contains the controller ID only, it implies that the default action of
the specified controller is requested.
By default, the default action is set as `index`. If you want to change the default value, simply override
this property in the controller class, like the following:
```php
namespace app\controllers;
use yii\web\Controller;
class SiteController extends Controller
{
public $defaultAction = 'home';
public function actionHome()
{
return $this->render('home');
}
}
```
## Controller Lifecycle <a name="controller-lifecycle"></a>
When processing a request, an [application](structure-applications.md) will create a controller
based on the requested [route](#routes). The controller will then undergo the following lifecycle
to fulfill the request:
1. The [[yii\base\Controller::init()]] method is called after the controller is created and configured.
2. The controller creates an action object based on the requested action ID:
* If the action ID is not specified, the [[yii\base\Controller::defaultAction|default action ID]] will be used.
* If the action ID is found in the [[yii\base\Controller::actions()|action map]], a standalone action
will be created;
* If the action ID is found to match an action method, an inline action will be created;
* Otherwise an [[yii\base\InvalidRouteException]] exception will be thrown.
3. The controller sequentially calls the `beforeAction()` method of the application, the module (if the controller
belongs to a module) and the controller.
* If one of the calls returns false, the rest of the uncalled `beforeAction()` will be skipped and the
action execution will be cancelled.
* By default, each `beforeAction()` method call will trigger a `beforeAction` event to which you can attach a handler.
4. The controller runs the action:
* The action parameters will be analyzed and populated from the request data;
5. The controller sequentially calls the `afterAction()` method of the controller, the module (if the controller
belongs to a module) and the application.
* By default, each `afterAction()` method call will trigger an `afterAction` event to which you can attach a handler.
6. The application will take the action result and assign it to the [response](runtime-responses.md).
## Best Practices <a name="best-practices"></a>
In a well-designed application, controllers are often very thin with each action containing only a few lines of code.
If your controller is rather complicated, it usually indicates that you should refactor it and move some code
to other classes.
In summary, controllers
* may access the [request](runtime-requests.md) data;
* may call methods of [models](structure-models.md) and other service components with request data;
* may use [views](structure-views.md) to compose responses;
* should NOT process the request data - this should be done in [models](structure-models.md);
* should avoid embedding HTML or other presentational code - this is better done in [views](structure-views.md).
docs/guide-zh-CN/structure-entry-scripts.md 0 → 100644
入口脚本
=============
入口脚本是应用启动流程中的第一环，一个应用（不管是网页应用还是控制台应用）只有一个入口脚本。终端用户的请求通过入口脚本实例化应用并将将请求转发到应用。
Web 应用的入口脚本必须放在终端用户能够访问的目录下，通常命名为 `index.php`，也可以使用 Web 服务器能定位到的其他名称。
控制台应用的入口脚本一般在应用根目录下命名为 `yii`（后缀为.php），该文件需要有执行权限，这样用户就能通过命令 `./yii <route> [arguments] [options]` 来运行控制台应用。
入口脚本主要完成以下工作：
* 定义全局常量；
* 注册 [Composer 自动加载器](http://getcomposer.org/doc/01-basic-usage.md#autoloading)；
* 包含 [[Yii]] 类文件；
* 加载应用配置；
* 创建一个[应用](structure-applications.md)实例并配置;
* 调用 [[yii\base\Application::run()]] 来处理请求。
## Web 应用 <a name="web-applications"></a>
以下是[基础应用模版](start-installation.md)入口脚本的代码：
```php
<?php
defined('YII_DEBUG') or define('YII_DEBUG', true);
defined('YII_ENV') or define('YII_ENV', 'dev');
// 注册 Composer 自动加载器
require(__DIR__ . '/../vendor/autoload.php');
// 包含 Yii 类文件
require(__DIR__ . '/../vendor/yiisoft/yii2/Yii.php');
// 加载应用配置
$config = require(__DIR__ . '/../config/web.php');
// 创建、配置、运行一个应用
(new yii\web\Application($config))->run();
```
## 控制台应用 <a name="console-applications"></a>
以下是一个控制台应用的入口脚本：
```php
#!/usr/bin/env php
<?php
/**
* Yii console bootstrap file.
*
* @link http://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
defined('YII_DEBUG') or define('YII_DEBUG', true);
// fcgi 默认没有定义 STDIN 和 STDOUT
defined('STDIN') or define('STDIN', fopen('php://stdin', 'r'));
defined('STDOUT') or define('STDOUT', fopen('php://stdout', 'w'));
// 注册 Composer 自动加载器
require(__DIR__ . '/vendor/autoload.php');
// 包含 Yii 类文件
require(__DIR__ . '/vendor/yiisoft/yii2/Yii.php');
// 加载应用配置
$config = require(__DIR__ . '/config/console.php');
$application = new yii\console\Application($config);
$exitCode = $application->run();
exit($exitCode);
```
## 定义常量 <a name="defining-constants"></a>
入口脚本是定义全局常量的最好地方，Yii 支持以下三个常量：
* `YII_DEBUG`：标识应用是否运行在调试模式。当在调试模式下，应用会保留更多日志信息，如果抛出异常，会显示详细的错误调用堆栈。因此，调试模式主要适合在开发阶段使用，`YII_DEBUG` 默认值为 false。
* `YII_ENV`：标识应用运行的环境，详情请查阅[配置](concept-configurations.md#environment-constants)章节。`YII_ENV` 默认值为 `'prod'`，表示应用运行在线上产品环境。
* `YII_ENABLE_ERROR_HANDLER`：标识是否启用 Yii 提供的错误处理，默认为 true。
当定义一个常量时，通常使用类似如下代码来定义：
```php
defined('YII_DEBUG') or define('YII_DEBUG', true);
```
上面的代码等同于:
```php
if (!defined('YII_DEBUG')) {
define('YII_DEBUG', true);
}
```
显然第一段代码更加简洁易懂。
常量定义应该在入口脚本的开头，这样包含其他 PHP 文件时，常量就能生效。
\ No newline at end of file
docs/guide-zh-CN/structure-models.md 0 → 100644
Models
======
Models are part of the [MVC](http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller) architecture.
They are objects representing business data, rules and logic.
You can create model classes by extending [[yii\base\Model]] or its child classes. The base class
[[yii\base\Model]] supports many useful features:
* [Attributes](#attributes): represent the business data and can be accessed like normal object properties
or array elements;
* [Attribute labels](#attribute-labels): specify the display labels for attributes;
* [Massive assignment](#massive-assignment): supports populating multiple attributes in a single step;
* [Validation rules](#validation-rules): ensures input data based on the declared validation rules;
* [Data Exporting](#data-exporting): allows model data to be exported in terms of arrays with customizable formats.
The `Model` class is also the base class for more advanced models, such as [Active Record](db-active-record.md).
Please refer to the relevant documentation for more details about these advanced models.
> Info: You are not required to base your model classes on [[yii\base\Model]]. However, because there are many Yii
components built to support [[yii\base\Model]], it is usually the preferable base class for a model.
## Attributes <a name="attributes"></a>
Models represent business data in terms of *attributes*. Each attribute is like a publicly accessible property
of a model. The method [[yii\base\Model::attributes()]] specifies what attributes a model class has.
You can access an attribute like accessing a normal object property:
```php
$model = new \app\models\ContactForm;
// "name" is an attribute of ContactForm
$model->name = 'example';
echo $model->name;
```
You can also access attributes like accessing array elements, thanks to the support for
[ArrayAccess](http://php.net/manual/en/class.arrayaccess.php) and [ArrayIterator](http://php.net/manual/en/class.arrayiterator.php)
by [[yii\base\Model]]:
```php
$model = new \app\models\ContactForm;
// accessing attributes like array elements
$model['name'] = 'example';
echo $model['name'];
// iterate attributes
foreach ($model as $name => $value) {
echo "$name: $value\n";
}
```
### Defining Attributes <a name="defining-attributes"></a>
By default, if your model class extends directly from [[yii\base\Model]], all its *non-static public* member
variables are attributes. For example, the `ContactForm` model class below has four attributes: `name`, `email`,
`subject` and `body`. The `ContactForm` model is used to represent the input data received from an HTML form.
```php
namespace app\models;
use yii\base\Model;
class ContactForm extends Model
{
public $name;
public $email;
public $subject;
public $body;
}
```
You may override [[yii\base\Model::attributes()]] to define attributes in a different way. The method should
return the names of the attributes in a model. For example, [[yii\db\ActiveRecord]] does so by returning
the column names of the associated database table as its attribute names. Note that you may also need to
override the magic methods such as `__get()`, `__set()` so that the attributes can be accessed like
normal object properties.
### Attribute Labels <a name="attribute-labels"></a>
When displaying values or getting input for attributes, you often need to display some labels associated
with attributes. For example, given an attribute named `firstName`, you may want to display a label `First Name`
which is more user-friendly when displayed to end users in places such as form inputs and error messages.
You can get the label of an attribute by calling [[yii\base\Model::getAttributeLabel()]]. For example,
```php
$model = new \app\models\ContactForm;
// displays "Name"
echo $model->getAttributeLabel('name');
```
By default, attribute labels are automatically generated from attribute names. The generation is done by
the method [[yii\base\Model::generateAttributeLabel()]]. It will turn camel-case variable names into
multiple words with the first letter in each word in upper case. For example, `username` becomes `Username`,
and `firstName` becomes `First Name`.
If you do not want to use automatically generated labels, you may override [[yii\base\Model::attributeLabels()]]
to explicitly declare attribute labels. For example,
```php
namespace app\models;
use yii\base\Model;
class ContactForm extends Model
{
public $name;
public $email;
public $subject;
public $body;
public function attributeLabels()
{
return [
'name' => 'Your name',
'email' => 'Your email address',
'subject' => 'Subject',
'body' => 'Content',
];
}
}
```
For applications supporting multiple languages, you may want to translate attribute labels. This can be done
in the [[yii\base\Model::attributeLabels()|attributeLabels()]] method as well, like the following:
```php
public function attributeLabels()
{
return [
'name' => \Yii::t('app', 'Your name'),
'email' => \Yii::t('app', 'Your email address'),
'subject' => \Yii::t('app', 'Subject'),
'body' => \Yii::t('app', 'Content'),
];
}
```
You may even conditionally define attribute labels. For example, based on the [scenario](#scenarios) the model
is being used in, you may return different labels for the same attribute.
> Info: Strictly speaking, attribute labels are part of [views](structure-views.md). But declaring labels
in models is often very convenient and can result in very clean and reusable code.
## Scenarios <a name="scenarios"></a>
A model may be used in different *scenarios*. For example, a `User` model may be used to collect user login inputs,
but it may also be used for the user registration purpose. In different scenarios, a model may use different
business rules and logic. For example, the `email` attribute may be required during user registration,
but not so during user login.
A model uses the [[yii\base\Model::scenario]] property to keep track of the scenario it is being used in.
By default, a model supports only a single scenario named `default`. The following code shows two ways of
setting the scenario of a model:
```php
// scenario is set as a property
$model = new User;
$model->scenario = 'login';
// scenario is set through configuration
$model = new User(['scenario' => 'login']);
```
By default, the scenarios supported by a model are determined by the [validation rules](#validation-rules) declared
in the model. However, you can customize this behavior by overriding the [[yii\base\Model::scenarios()]] method,
like the following:
```php
namespace app\models;
use yii\db\ActiveRecord;
class User extends ActiveRecord
{
public function scenarios()
{
return [
'login' => ['username', 'password'],
'register' => ['username', 'email', 'password'],
];
}
}
```
> Info: In the above and following examples, the model classes are extending from [[yii\db\ActiveRecord]]
because the usage of multiple scenarios usually happens to [Active Record](db-active-record.md) classes.
The `scenarios()` method returns an array whose keys are the scenario names and values the corresponding
*active attributes*. An active attribute can be [massively assigned](#massive-assignment) and is subject
to [validation](#validation-rules). In the above example, the `username` and `password` attributes are active
in the `login` scenario; while in the `register` scenario, `email` is also active besides `username` and `password`.
The default implementation of `scenarios()` will return all scenarios found in the validation rule declaration
method [[yii\base\Model::rules()]]. When overriding `scenarios()`, if you want to introduce new scenarios
in addition to the default ones, you may write code like the following:
```php
namespace app\models;
use yii\db\ActiveRecord;
class User extends ActiveRecord
{
public function scenarios()
{
$scenarios = parent::scenarios();
$scenarios['login'] = ['username', 'password'];
$scenarios['register'] = ['username', 'email', 'password'];
return $scenarios;
}
}
```
The scenario feature is primarily used by [validation](#validation-rules) and [massive attribute assignment](#massive-assignment).
You can, however, use it for other purposes. For example, you may declare [attribute labels](#attribute-labels)
differently based on the current scenario.
## Validation Rules <a name="validation-rules"></a>
When the data for a model is received from end users, it should be validated to make sure it satisfies
certain rules (called *validation rules*, also known as *business rules*). For example, given a `ContactForm` model,
you may want to make sure all attributes are not empty and the `email` attribute contains a valid email address.
If the values for some attributes do not satisfy the corresponding business rules, appropriate error messages
should be displayed to help the user to fix the errors.
You may call [[yii\base\Model::validate()]] to validate the received data. The method will use
the validation rules declared in [[yii\base\Model::rules()]] to validate every relevant attribute. If no error
is found, it will return true. Otherwise, it will keep the errors in the [[yii\base\Model::errors]] property
and return false. For example,
```php
$model = new \app\models\ContactForm;
// populate model attributes with user inputs
$model->attributes = \Yii::$app->request->post('ContactForm');
if ($model->validate()) {
// all inputs are valid
} else {
// validation failed: $errors is an array containing error messages
$errors = $model->errors;
}
```
To declare validation rules associated with a model, override the [[yii\base\Model::rules()]] method by returning
the rules that the model attributes should satisfy. The following example shows the validation rules declared
for the `ContactForm` model:
```php
public function rules()
{
return [
// the name, email, subject and body attributes are required
[['name', 'email', 'subject', 'body'], 'required'],
// the email attribute should be a valid email address
['email', 'email'],
];
}
```
A rule can be used to validate one or multiple attributes, and an attribute may be validated by one or multiple rules.
Please refer to the [Validating Input](input-validation.md) section for more details on how to declare
validation rules.
Sometimes, you may want a rule to be applied only in certain [scenarios](#scenarios). To do so, you can
specify the `on` property of a rule, like the following:
```php
public function rules()
{
return [
// username, email and password are all required in "register" scenario
[['username', 'email', 'password'], 'required', 'on' => 'register'],
// username and password are required in "login" scenario
[['username', 'password'], 'required', 'on' => 'login'],
];
}
```
If you do not specify the `on` property, the rule would be applied in all scenarios. A rule is called
an *active rule* if it can be applied in the current [[yii\base\Model::scenario|scenario]].
An attribute will be validated if and only if it is an active attribute declared in `scenarios()` and
is associated with one or multiple active rules declared in `rules()`.
## Massive Assignment <a name="massive-assignment"></a>
Massive assignment is a convenient way of populating a model with user inputs using a single line of code.
It populates the attributes of a model by assigning the input data directly to the [[yii\base\Model::$attributes]]
property. The following two pieces of code are equivalent, both trying to assign the form data submitted by end users
to the attributes of the `ContactForm` model. Clearly, the former, which uses massive assignment, is much cleaner
and less error prone than the latter:
```php
$model = new \app\models\ContactForm;
$model->attributes = \Yii::$app->request->post('ContactForm');
```
```php
$model = new \app\models\ContactForm;
$data = \Yii::$app->request->post('ContactForm', []);
$model->name = isset($data['name']) ? $data['name'] : null;
$model->email = isset($data['email']) ? $data['email'] : null;
$model->subject = isset($data['subject']) ? $data['subject'] : null;
$model->body = isset($data['body']) ? $data['body'] : null;
```
### Safe Attributes <a name="safe-attributes"></a>
Massive assignment only applies to the so-called *safe attributes* which are the attributes listed in
[[yii\base\Model::scenarios()]] for the current [[yii\base\Model::scenario|scenario]] of a model.
For example, if the `User` model has the following scenario declaration, then when the current scenario
is `login`, only the `username` and `password` can be massively assigned. Any other attributes will
be kept untouched.
```php
public function scenarios()
{
return [
'login' => ['username', 'password'],
'register' => ['username', 'email', 'password'],
];
}
```
> Info: The reason that massive assignment only applies to safe attributes is because you want to
control which attributes can be modified by end user data. For example, if the `User` model
has a `permission` attribute which determines the permission assigned to the user, you would
like this attribute to be modifiable by administrators through a backend interface only.
Because the default implementation of [[yii\base\Model::scenarios()]] will return all scenarios and attributes
found in [[yii\base\Model::rules()]], if you do not override this method, it means an attribute is safe as long
as it appears in one of the active validation rules.
For this reason, a special validator aliased `safe` is provided so that you can declare an attribute
to be safe without actually validating it. For example, the following rules declare that both `title`
and `description` are safe attributes.
```php
public function rules()
{
return [
[['title', 'description'], 'safe'],
];
}
```
### Unsafe Attributes <a name="unsafe-attributes"></a>
As described above, the [[yii\base\Model::scenarios()]] method serves for two purposes: determining which attributes
should be validated, and determining which attributes are safe. In some rare cases, you may want to validate
an attribute but do not want to mark it safe. You can do so by prefixing an exclamation mark `!` to the attribute
name when declaring it in `scenarios()`, like the `secret` attribute in the following:
```php
public function scenarios()
{
return [
'login' => ['username', 'password', '!secret'],
];
}
```
When the model is in the `login` scenario, all three attributes will be validated. However, only the `username`
and `password` attributes can be massively assigned. To assign an input value to the `secret` attribute, you
have to do it explicitly as follows,
```php
$model->secret = $secret;
```
## Data Exporting <a name="data-exporting"></a>
Models often need to be exported in different formats. For example, you may want to convert a collection of
models into JSON or Excel format. The exporting process can be broken down into two independent steps.
In the first step, models are converted into arrays; in the second step, the arrays are converted into
target formats. You may just focus on the first step, because the second step can be achieved by generic
data formatters, such as [[yii\web\JsonResponseFormatter]].
The simplest way of converting a model into an array is to use the [[yii\base\Model::$attributes]] property.
For example,
```php
$post = \app\models\Post::findOne(100);
$array = $post->attributes;
```
By default, the [[yii\base\Model::$attributes]] property will return the values of *all* attributes
declared in [[yii\base\Model::attributes()]].
A more flexible and powerful way of converting a model into an array is to use the [[yii\base\Model::toArray()]]
method. Its default behavior is the same as that of [[yii\base\Model::$attributes]]. However, it allows you
to choose which data items, called *fields*, to be put in the resulting array and how they should be formatted.
In fact, it is the default way of exporting models in RESTful Web service development, as described in
the [Response Formatting](rest-response-formatting.md).
### Fields <a name="fields"></a>
A field is simply a named element in the array that is obtained by calling the [[yii\base\Model::toArray()]] method
of a model.
By default, field names are equivalent to attribute names. However, you can change this behavior by overriding
the [[yii\base\Model::fields()|fields()]] and/or [[yii\base\Model::extraFields()|extraFields()]] methods. Both methods
should return a list of field definitions. The fields defined by `fields()` are default fields, meaning that
`toArray()` will return these fields by default. The `extraFields()` method defines additionally available fields
which can also be returned by `toArray()` as long as you specify them via the `$expand` parameter. For example,
the following code will return all fields defined in `fields()` and the `prettyName` and `fullAddress` fields
if they are defined in `extraFields()`.
```php
$array = $model->toArray([], ['prettyName', 'fullAddress']);
```
You can override `fields()` to add, remove, rename or redefine fields. The return value of `fields()`
should be an array. The array keys are the field names, and the array values are the corresponding
field definitions which can be either property/attribute names or anonymous functions returning the
corresponding field values. In the special case when a field name is the same as its defining attribute
name, you can omit the array key. For example,
```php
// explicitly list every field, best used when you want to make sure the changes
// in your DB table or model attributes do not cause your field changes (to keep API backward compatibility).
public function fields()
{
return [
// field name is the same as the attribute name
'id',
// field name is "email", the corresponding attribute name is "email_address"
'email' => 'email_address',
// field name is "name", its value is defined by a PHP callback
'name' => function () {
return $this->first_name . ' ' . $this->last_name;
},
];
}
// filter out some fields, best used when you want to inherit the parent implementation
// and blacklist some sensitive fields.
public function fields()
{
$fields = parent::fields();
// remove fields that contain sensitive information
unset($fields['auth_key'], $fields['password_hash'], $fields['password_reset_token']);
return $fields;
}
```
> Warning: Because by default all attributes of a model will be included in the exported array, you should
> examine your data to make sure they do not contain sensitive information. If there is such information,
> you should override `fields()` to filter them out. In the above example, we choose
> to filter out `auth_key`, `password_hash` and `password_reset_token`.
## Best Practices <a name="best-practices"></a>
Models are the central places to represent business data, rules and logic. They often need to be reused
in different places. In a well-designed application, models are usually much fatter than
[controllers](structure-controllers.md).
In summary, models
* may contain attributes to represent business data;
* may contain validation rules to ensure the data validity and integrity;
* may contain methods implementing business logic;
* should NOT directly access request, session, or any other environmental data. These data should be injected
by [controllers](structure-controllers.md) into models;
* should avoid embedding HTML or other presentational code - this is better done in [views](structure-views.md);
* avoid having too many [scenarios](#scenarios) in a single model.
You may usually consider the last recommendation above when you are developing large complex systems.
In these systems, models could be very fat because they are used in many places and may thus contain many sets
of rules and business logic. This often ends up in a nightmare in maintaining the model code
because a single touch of the code could affect several different places. To make the mode code more maintainable,
you may take the following strategy:
* Define a set of base model classes that are shared by different [applications](structure-applications.md) or
[modules](structure-modules.md). These model classes should contain minimal sets of rules and logic that
are common among all their usages.
* In each [application](structure-applications.md) or [module](structure-modules.md) that uses a model,
define a concrete model class by extending from the corresponding base model class. The concrete model classes
should contain rules and logic that are specific for that application or module.
For example, in the [Advanced Application Template](tutorial-advanced-app.md), you may define a base model
class `common\models\Post`. Then for the front end application, you define and use a concrete model class
`frontend\models\Post` which extends from `common\models\Post`. And similarly for the back end application,
you define `backend\models\Post`. With this strategy, you will be sure that the code in `frontend\models\Post`
is only specific to the front end application, and if you make any change to it, you do not need to worry if
the change may break the back end application.
docs/guide-zh-CN/structure-overview.md 0 → 100644
总览
========
Yii 应用参照[模型-视图-控制器 （MVC）](http://wikipedia.org/wiki/Model-view-controller)
设计模式来组织。 [模型](structure-models.md)代表数据、业务逻辑和规则；[视图](structure-views.md)展示模型的输出；[控制器](structure-controllers.md)接受出入并将其转换为[模型](structure-models.md)和[视图](structure-views.md)命令。
除了 MVC, Yii 应用还有以下部分：
* [入口脚本](structure-entry-scripts.md)：终端用户能直接访问的 PHP 脚本，负责启动一个请求处理周期。
* [应用](structure-applications.md)：能全局范围内访问的对象，管理协调组件来完成请求.
* [应用组件](structure-application-components.md)：在应用中注册的对象，提供不同的功能来完成请求。
* [模块](structure-modules.md)：包含完整 MVC 结构的独立包，一个应用可以由多个模块组建。
* [过滤器](structure-filters.md)：控制器在处理请求之前或之后需要触发执行的代码。
* [小部件](structure-widgets.md)：可嵌入到[视图](structure-views.md)中的对象，可包含控制器逻辑，可被不同视图重复调用。
下面的示意图展示了 Yii 应用的静态结构：
![Yii应用静态结构](images/application-structure.png)
docs/guide-zh-CN/structure-views.md 0 → 100644
Views
=====
Views are part of the [MVC](http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller) architecture.
They are code responsible for presenting data to end users. In a Web application, views are usually created
in terms of *view templates* which are PHP script files containing mainly HTML code and presentational PHP code.
They are managed by the [[yii\web\View|view]] application component which provides commonly used methods
to facilitate view composition and rendering. For simplicity, we often call view templates or view template files
as views.
## Creating Views <a name="creating-views"></a>
As aforementioned, a view is simply a PHP script mixed with HTML and PHP code. The following is the view
that presents a login form. As you can see, PHP code is used to generate the dynamic content, such as the
page title and the form, while HTML code organizes them into a presentable HTML page.
```php
<?php
use yii\helpers\Html;
use yii\widgets\ActiveForm;
/* @var $this yii\web\View */
/* @var $form yii\widgets\ActiveForm */
/* @var $model app\models\LoginForm */
$this->title = 'Login';
?>
<h1><?= Html::encode($this->title) ?></h1>
<p>Please fill out the following fields to login:</p>
<?php $form = ActiveForm::begin(); ?>
<?= $form->field($model, 'username') ?>
<?= $form->field($model, 'password')->passwordInput() ?>
<?= Html::submitButton('Login') ?>
<?php ActiveForm::end(); ?>
```
Within a view, you can access `$this` which refers to the [[yii\web\View|view component]] managing
and rendering this view template.
Besides `$this`, there may be other predefined variables in a view, such as `$model` in the above
example. These variables represent the data that are *pushed* into the view by [controllers](structure-controllers.md)
or other objects whose trigger the [view rendering](#rendering-views).
> Tip: The predefined variables are listed in a comment block at beginning of a view so that they can
be recognized by IDEs. It is also a good way of documenting your views.
### Security <a name="security"></a>
When creating views that generate HTML pages, it is important that you encode and/or filter the data coming
from end users before presenting them. Otherwise, your application may be subject to
[cross-site scripting](http://en.wikipedia.org/wiki/Cross-site_scripting) attacks.
To display a plain text, encode it first by calling [[yii\helpers\Html::encode()]]. For example, the following code
encodes the user name before displaying it:
```php
<?php
use yii\helpers\Html;
?>
<div class="username">
<?= Html::encode($user->name) ?>
</div>
```
To display HTML content, use [[yii\helpers\HtmlPurifier]] to filter the content first. For example, the following
code filters the post content before displaying it:
```php
<?php
use yii\helpers\HtmlPurifier;
?>
<div class="post">
<?= HtmlPurifier::process($post->text) ?>
</div>
```
> Tip: While HTMLPurifier does excellent job in making output safe, it is not fast. You should consider
[caching](caching-overview.md) the filtering result if your application requires high performance.
### Organizing Views <a name="organizing-views"></a>
Like [controllers](structure-controllers.md) and [models](structure-models.md), there are conventions to organize views.
* For views rendered by a controller, they should be put under the directory `@app/views/ControllerID` by default,
where `ControllerID` refers to the [controller ID](structure-controllers.md#routes). For example, if
the controller class is `PostController`, the directory would be `@app/views/post`; If it is `PostCommentController`,
the directory would be `@app/views/post-comment`. In case the controller belongs to a module, the directory
would be `views/ControllerID` under the [[yii\base\Module::basePath|module directory]].
* For views rendered in a [widget](structure-widgets.md), they should be put under the `WidgetPath/views` directory by
default, where `WidgetPath` stands for the directory containing the widget class file.
* For views rendered by other objects, it is recommended that you follow the similar convention as that for widgets.
You may customize these default view directories by overriding the [[yii\base\ViewContextInterface::getViewPath()]]
method of controllers or widgets.
## Rendering Views <a name="rendering-views"></a>
You can render views in [controllers](structure-controllers.md), [widgets](structure-widgets.md), or any
other places by calling view rendering methods. These methods share a similar signature shown as follows,
```
/**
* @param string $view view name or file path, depending on the actual rendering method
* @param array $params the data to be passed to the view
* @return string rendering result
*/
methodName($view, $params = [])
```
### Rendering in Controllers <a name="rendering-in-controllers"></a>
Within [controllers](structure-controllers.md), you may call the following controller methods to render views:
* [[yii\base\Controller::render()|render()]]: renders a [named view](#named-views) and applies a [layout](#layouts)
to the rendering result.
* [[yii\base\Controller::renderPartial()|renderPartial()]]: renders a [named view](#named-views) without any layout.
* [[yii\web\Controller::renderAjax()|renderAjax()]]: renders a [named view](#named-views) without any layout,
and injects all registered JS/CSS scripts and files. It is usually used in response to AJAX Web requests.
* [[yii\base\Controller::renderFile()|renderFile()]]: renders a view specified in terms of a view file path or
[alias](concept-aliases.md).
For example,
```php
namespace app\controllers;
use Yii;
use app\models\Post;
use yii\web\Controller;
use yii\web\NotFoundHttpException;
class PostController extends Controller
{
public function actionView($id)
{
$model = Post::findOne($id);
if ($model === null) {
throw new NotFoundHttpException;
}
// renders a view named "view" and applies a layout to it
return $this->render('view', [
'model' => $model,
]);
}
}
```
### Rendering in Widgets <a name="rendering-in-widgets"></a>
Within [widgets](structure-widgets.md), you may call the following widget methods to render views.
* [[yii\base\Widget::render()|render()]]: renders a [named view](#named-views).
* [[yii\base\Widget::renderFile()|renderFile()]]: renders a view specified in terms of a view file path or
[alias](concept-aliases.md).
For example,
```php
namespace app\components;
use yii\base\Widget;
use yii\helpers\Html;
class ListWidget extends Widget
{
public $items = [];
public function run()
{
// renders a view named "list"
return $this->render('list', [
'items' => $this->items,
]);
}
}
```
### Rendering in Views <a name="rendering-in-views"></a>
You can render a view within another view by calling one of the following methods provided by the [[yii\base\View|view component]]:
* [[yii\base\View::render()|render()]]: renders a [named view](#named-views).
* [[yii\web\View::renderAjax()|renderAjax()]]: renders a [named view](#named-views) and injects all registered
JS/CSS scripts and files. It is usually used in response to AJAX Web requests.
* [[yii\base\View::renderFile()|renderFile()]]: renders a view specified in terms of a view file path or
[alias](concept-aliases.md).
For example, the following code in a view renders the `_overview.php` view file which is in the same directory
as the view being currently rendered. Remember that `$this` in a view refers to the [[yii\base\View|view]] component:
```php
<?= $this->render('_overview') ?>
```
### Rendering in Other Places <a name="rendering-in-other-places"></a>
In any place, you can get access to the [[yii\base\View|view]] application component by the expression
`Yii::$app->view` and then call its aforementioned methods to render a view. For example,
```php
// displays the view file "@app/views/site/license.php"
echo \Yii::$app->view->renderFile('@app/views/site/license.php');
```
### Named Views <a name="named-views"></a>
When you render a view, you can specify the view using either a view name or a view file path/alias. In most cases,
you would use the former because it is more concise and flexible. We call views specified using names as *named views*.
A view name is resolved into the corresponding view file path according to the following rules:
* A view name may omit the file extension name. In this case, `.php` will be used as the extension. For example,
the view name `about` corresponds to the file name `about.php`.
* If the view name starts with double slashes `//`, the corresponding view file path would be `@app/views/ViewName`.
That is, the view is looked for under the [[yii\base\Application::viewPath|application's view path]].
For example, `//site/about` will be resolved into `@app/views/site/about.php`.
* If the view name starts with a single slash `/`, the view file path is formed by prefixing the view name
with the [[yii\base\Module::viewPath|view path]] of the currently active [module](structure-modules.md).
If there is no active module, `@app/views/ViewName` will be used. For example, `/user/create` will be resolved into
`@app/modules/user/views/user/create.php`, if the currently active module is `user`. If there is no active module,
the view file path would be `@app/views/user/create.php`.
* If the view is rendered with a [[yii\base\View::context|context]] and the context implements [[yii\base\ViewContextInterface]],
the view file path is formed by prefixing the [[yii\base\ViewContextInterface::getViewPath()|view path]] of the
context to the view name. This mainly applies to the views rendered within controllers and widgets. For example,
`site/about` will be resolved into `@app/views/site/about.php` if the context is the controller `SiteController`.
* If a view is rendered within another view, the directory containing the other view file will be prefixed to
the new view name to form the actual view file path. For example, `item` will be resolved into `@app/views/post/item`
if it is being rendered in the view `@app/views/post/index.php`.
According to the above rules, calling `$this->render('view')` in a controller `app\controllers\PostController` will
actually render the view file `@app/views/post/view.php`, while calling `$this->render('_overview')` in that view
will render the view file `@app/views/post/_overview.php`.
### Accessing Data in Views <a name="accessing-data-in-views"></a>
There are two approaches to access data within a view: push and pull.
By passing the data as the second parameter to the view rendering methods, you are using the push approach.
The data should be represented as an array of name-value pairs. When the view is being rendered, the PHP
`extract()` function will be called on this array so that the array is extracted into variables in the view.
For example, the following view rendering code in a controller will push two variables to the `report` view:
`$foo = 1` and `$bar = 2`.
```php
echo $this->render('report', [
'foo' => 1,
'bar' => 2,
]);
```
The pull approach actively retrieves data from the [[yii\base\View|view component]] or other objects accessible
in views (e.g. `Yii::$app`). Using the code below as an example, within the view you can get the controller object
by the expression `$this->context`. And as a result, it is possible for you to access any properties or methods
of the controller in the `report` view, such as the controller ID shown in the following:
```php
The controller ID is: <?= $this->context->id ?>
?>
```
The push approach is usually the preferred way of accessing data in views, because it makes views less dependent
on context objects. Its drawback is that you need to manually build the data array all the time, which could
become tedious and error prone if a view is shared and rendered in different places.
### Sharing Data among Views <a name="sharing-data-among-views"></a>
The [[yii\base\View|view component]] provides the [[yii\base\View::params|params]] property that you can use
to share data among views.
For example, in an `about` view, you can have the following code which specifies the current segment of the
breadcrumbs.
```php
$this->params['breadcrumbs'][] = 'About Us';
```
Then, in the [layout](#layouts) file, which is also a view, you can display the breadcrumbs using the data
passed along [[yii\base\View::params|params]]:
```php
<?= yii\widgets\Breadcrumbs::widget([
'links' => isset($this->params['breadcrumbs']) ? $this->params['breadcrumbs'] : [],
]) ?>
```
## Layouts <a name="layouts"></a>
Layouts are a special type of views that represent the common parts of multiple views. For example, the pages
for most Web applications share the same page header and footer. While you can repeat the same page header and footer
in every view, a better way is to do this once in a layout and embed the rendering result of a content view at
an appropriate place in the layout.
### Creating Layouts <a name="creating-layouts"></a>
Because layouts are also views, they can be created in the similar way as normal views. By default, layouts
are stored in the directory `@app/views/layouts`. For layouts used within a [module](structure-modules.md),
they should be stored in the `views/layouts` directory under the [[yii\base\Module::basePath|module directory]].
You may customize the default layout directory by configuring the [[yii\base\Module::layoutPath]] property of
the application or modules.
The following example shows how a layout looks like. Note that for illustrative purpose, we have greatly simplified
the code in the layout. In practice, you may want to add more content to it, such as head tags, main menu, etc.
```php
<?php
use yii\helpers\Html;
/* @var $this yii\web\View */
/* @var $content string */
?>
<?php $this->beginPage() ?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8"/>
<?= Html::csrfMetaTags() ?>
<title><?= Html::encode($this->title) ?></title>
<?php $this->head() ?>
</head>
<body>
<?php $this->beginBody() ?>
<header>My Company</header>
<?= $content ?>
<footer>&copy; 2014 by My Company</footer>
<?php $this->endBody() ?>
</body>
</html>
<?php $this->endPage() ?>
```
As you can see, the layout generates the HTML tags that are common to all pages. Within the `<body>` section,
the layout echoes the `$content` variable which represents the rendering result of content views and is pushed
into the layout when [[yii\base\Controller::render()]] is called.
Most layouts should call the following methods like shown in the above code. These methods mainly trigger events
about the rendering process so that scripts and tags registered in other places can be properly injected into
the places where these methods are called.
- [[yii\base\View::beginPage()|beginPage()]]: This method should be called at the very beginning of the layout.
It triggers the [[yii\base\View::EVENT_BEGIN_PAGE|EVENT_BEGIN_PAGE]] event which indicates the beginning of a page.
- [[yii\base\View::endPage()|endPage()]]: This method should be called at the end of the layout.
It triggers the [[yii\base\View::EVENT_END_PAGE|EVENT_END_PAGE]] event which indicates the end of a page.
- [[yii\web\View::head()|head()]]: This method should be called within the `<head>` section of an HTML page.
It generates a placeholder which will be replaced with the registered head HTML code (e.g. link tags, meta tags)
when a page finishes rendering.
- [[yii\web\View::beginBody()|beginBody()]]: This method should be called at the beginning of the `<body>` section.
It triggers the [[yii\web\View::EVENT_BEGIN_BODY|EVENT_BEGIN_BODY]] event and generates a placeholder which will
be replaced by the registered HTML code (e.g. JavaScript) targeted at the body begin position.
- [[yii\web\View::endBody()|endBody()]]: This method should be called at the end of the `<body>` section.
It triggers the [[yii\web\View::EVENT_END_BODY|EVENT_END_BODY]] event and generates a placeholder which will
be replaced by the registered HTML code (e.g. JavaScript) targeted at the body end position.
### Accessing Data in Layouts <a name="accessing-data-in-layouts"></a>
Within a layout, you have access to two predefined variables: `$this` and `$content`. The former refers to
the [[yii\base\View|view]] component, like in normal views, while the latter contains the rendering result of a content
view which is rendered by calling the [[yii\base\Controller::render()|render()]] method in controllers.
If you want to access other data in layouts, you have to use the pull method as described in
the [Accessing Data in Views](#accessing-data-in-views) subsection. If you want to pass data from a content view
to a layout, you may use the method described in the [Sharing Data among Views](#sharing-data-among-views) subsection.
### Using Layouts <a name="using-layouts"></a>
As described in the [Rendering in Controllers](#rendering-in-controllers) subsection, when you render a view
by calling the [[yii\base\Controller::render()|render()]] method in a controller, a layout will be applied
to the rendering result. By default, the layout `@app/views/layouts/main.php` will be used.
You may use a different layout by configuring either [[yii\base\Application::layout]] or [[yii\base\Controller::layout]].
The former governs the layout used by all controllers, while the latter overrides the former for individual controllers.
For example, the following code makes the `post` controller to use `@app/views/layouts/post.php` as the layout
when rendering its views. Other controllers, assuming their `layout` property is untouched, will still use the default
`@app/views/layouts/main.php` as the layout.
```php
namespace app\controllers;
use yii\web\Controller;
class PostController extends Controller
{
public $layout = 'post';
// ...
}
```
For controllers belonging to a module, you may also configure the module's [[yii\base\Module::layout|layout]] property to
use a particular layout for these controllers.
Because the `layout` property may be configured at different levels (controllers, modules, application),
behind the scene Yii takes two steps to determine what is the actual layout file being used for a particular controller.
In the first step, it determines the layout value and the context module:
- If the [[yii\base\Controller::layout]] property of the controller is not null, use it as the layout value and
the [[yii\base\Controller::module|module]] of the controller as the context module.
- If [[yii\base\Controller::layout|layout]] is null, search through all ancestor modules (including the application itself) of the controller and
find the first module whose [[yii\base\Module::layout|layout]] property is not null. Use that module and
its [[yii\base\Module::layout|layout]] value as the context module and the chosen layout value.
If such a module cannot be found, it means no layout will be applied.
In the second step, it determines the actual layout file according to the layout value and the context module
determined in the first step. The layout value can be:
- a path alias (e.g. `@app/views/layouts/main`).
- an absolute path (e.g. `/main`): the layout value starts with a slash. The actual layout file will be
looked for under the application's [[yii\base\Application::layoutPath|layout path]] which defaults to
`@app/views/layouts`.
- a relative path (e.g. `main`): the actual layout file will be looked for under the context module's
[[yii\base\Module::layoutPath|layout path]] which defaults to the `views/layouts` directory under the
[[yii\base\Module::basePath|module directory]].
- the boolean value `false`: no layout will be applied.
If the layout value does not contain a file extension, it will use the default one `.php`.
### Nested Layouts <a name="nested-layouts"></a>
Sometimes you may want to nest one layout in another. For example, in different sections of a Web site, you
want to use different layouts, while all these layouts share the same basic layout that generates the overall
HTML5 page structure. You can achieve this goal by calling [[yii\base\View::beginContent()|beginContent()]] and
[[yii\base\View::endContent()|endContent()]] in the child layouts like the following:
```php
<?php $this->beginContent('@app/views/layouts/base.php'); ?>
...child layout content here...
<?php $this->endContent(); ?>
```
As shown above, the child layout content should be enclosed within [[yii\base\View::beginContent()|beginContent()]] and
[[yii\base\View::endContent()|endContent()]]. The parameter passed to [[yii\base\View::beginContent()|beginContent()]]
specifies what is the parent layout. It can be either a layout file or alias.
Using the above approach, you can nest layouts in more than one levels.
### Using Blocks <a name="using-blocks"></a>
Blocks allow you to specify the view content in one place while displaying it in another. They are often used together
with layouts. For example, you can define a block in a content view and display it in the layout.
You call [[yii\base\View::beginBlock()|beginBlock()]] and [[yii\base\View::endBlock()|endBlock()]] to define a block.
The block can then be accessed via `$view->blocks[$blockID]`, where `$blockID` stands for a unique ID that you assign
to the block when defining it.
The following example shows how you can use blocks to customize specific parts of a layout in a content view.
First, in a content view, define one or multiple blocks:
```php
...
<?php $this->beginBlock('block1'); ?>
...content of block1...
<?php $this->endBlock(); ?>
...
<?php $this->beginBlock('block3'); ?>
...content of block3...
<?php $this->endBlock(); ?>
```
Then, in the layout view, render the blocks if they are available, or display some default content if a block is
not defined.
```php
...
<?php if (isset($this->blocks['block1'])): ?>
<?= $this->blocks['block1'] ?>
<?php else: ?>
... default content for block1 ...
<?php endif; ?>
...
<?php if (isset($this->blocks['block2'])): ?>
<?= $this->blocks['block2'] ?>
<?php else: ?>
... default content for block2 ...
<?php endif; ?>
...
<?php if (isset($this->blocks['block3'])): ?>
<?= $this->blocks['block3'] ?>
<?php else: ?>
... default content for block3 ...
<?php endif; ?>
...
```
## Using View Components <a name="using-view-components"></a>
[[yii\base\View|View components]] provides many view-related features. While you can get view components
by creating individual instances of [[yii\base\View]] or its child class, in most cases you will mainly use
the `view` application component. You can configure this component in [application configurations](structure-applications.md#application-configurations)
like the following:
```php
[
// ...
'components' => [
'view' => [
'class' => 'app\components\View',
],
// ...
],
]
```
View components provide the following useful view-related features, each described in more details in a separate section:
* [theming](output-theming.md): allows you to develop and change the theme for your Web site.
* [fragment caching](caching-fragment.md): allows you to cache a fragment within a Web page.
* [client script handling](output-client-scripts.md): supports CSS and JavaScript registration and rendering.
* [asset bundle handling](structure-assets.md): supports registering and rendering of [asset bundles](structure-assets.md).
* [alternative template engines](tutorial-template-engines.md): allows you to use other template engines, such as
[Twig](http://twig.sensiolabs.org/), [Smarty](http://www.smarty.net/).
You may also frequently use the following minor yet useful features when you are developing Web pages.
### Setting Page Titles <a name="setting-page-titles"></a>
Every Web page should have a title. Normally the title tag is being displayed in a [layout](#layouts). However, in practice
the title is often determined in content views rather than layouts. To solve this problem, [[yii\web\View]] provides
the [[yii\web\View::title|title]] property for you to pass the title information from content views to layouts.
To make use of this feature, in each content view, you can set the page title like the following:
```php
<?php
$this->title = 'My page title';
?>
```
Then in the layout, make sure you have the following code in the `<head>` section:
```php
<title><?= Html::encode($this->title) ?></title>
```
### Registering Meta Tags <a name="registering-meta-tags"></a>
Web pages usually need to generate various meta tags needed by different parties. Like page titles, meta tags
appear in the `<head>` section and are usually generated in layouts.
If you want to specify what meta tags to generate in content views, you can call [[yii\web\View::registerMetaTag()]]
in a content view, like the following:
```php
<?php
$this->registerMetaTag(['name' => 'keywords', 'content' => 'yii, framework, php']);
?>
```
The above code will register a "keywords" meta tag with the view component. The registered meta tag is
rendered after the layout finishes rendering. By then, the following HTML code will be inserted
at the place where you call [[yii\web\View::head()]] in the layout and generate the following HTML code:
```php
<meta name="keywords" content="yii, framework, php">
```
Note that if you call [[yii\web\View::registerMetaTag()]] multiple times, it will register multiple meta tags,
regardless whether the meta tags are the same or not.
To make sure there is only a single instance of a meta tag type, you can specify a key as a second parameter when calling the method.
For example, the following code registers two "description" meta tags. However, only the second one will be rendered.
```html
$this->registerMetaTag(['name' => 'description', 'content' => 'This is my cool website made with Yii!'], 'description');
$this->registerMetaTag(['name' => 'description', 'content' => 'This website is about funny raccoons.'], 'description');
```
### Registering Link Tags <a name="registering-link-tags"></a>
Like [meta tags](#adding-meta-tags), link tags are useful in many cases, such as customizing favicon, pointing to
RSS feed or delegating OpenID to another server. You can work with link tags in the similar way as meta tags
by using [[yii\web\View::registerLinkTag()]]. For example, in a content view, you can register a link tag like follows,
```php
$this->registerLinkTag([
'title' => 'Live News for Yii',
'rel' => 'alternate',
'type' => 'application/rss+xml',
'href' => 'http://www.yiiframework.com/rss.xml/',
]);
```
The code above will result in
```html
<link title="Live News for Yii" rel="alternate" type="application/rss+xml" href="http://www.yiiframework.com/rss.xml/">
```
Similar as [[yii\web\View::registerMetaTag()|registerMetaTags()]], you can specify a key when calling
[[yii\web\View::registerLinkTag()|registerLinkTag()]] to avoid generated repeated link tags.
## View Events <a name="view-events"></a>
[[yii\base\View|View components]] trigger several events during the view rendering process. You may respond
to these events to inject content into views or process the rendering results before they are sent to end users.
- [[yii\base\View::EVENT_BEFORE_RENDER|EVENT_BEFORE_RENDER]]: triggered at the beginning of rendering a file
in a controller. Handlers of this event may set [[yii\base\ViewEvent::isValid]] to be false to cancel the rendering process.
- [[yii\base\View::EVENT_AFTER_RENDER|EVENT_AFTER_RENDER]]: triggered by the call of [[yii\base\View::beginPage()]] in layouts.
Handlers of this event may obtain the rendering result through [[yii\base\ViewEvent::output]] and may modify
this property to change the rendering result.
- [[yii\base\View::EVENT_BEGIN_PAGE|EVENT_BEGIN_PAGE]]: triggered by the call of [[yii\base\View::beginPage()]] in layouts.
- [[yii\base\View::EVENT_END_PAGE|EVENT_END_PAGE]]: triggered by the call of [[yii\base\View::endPage()]] in layouts.
- [[yii\web\View::EVENT_BEGIN_BODY|EVENT_BEGIN_BODY]]: triggered by the call of [[yii\web\View::beginBody()]] in layouts.
- [[yii\web\View::EVENT_END_BODY|EVENT_END_BODY]]: triggered by the call of [[yii\web\View::endBody()]] in layouts.
For example, the following code injects the current date at the end of the page body:
```php
\Yii::$app->view->on(View::EVENT_END_BODY, function () {
echo date('Y-m-d');
});
```
## Rendering Static Pages <a name="rendering-static-pages"></a>
Static pages refer to those Web pages whose main content are mostly static without the need of accessing
dynamic data pushed from controllers.
You can output static pages by putting their code in the view, and then using the code like the following in a controller:
```php
public function actionAbout()
{
return $this->render('about');
}
```
If a Web site contains many static pages, it would be very tedious repeating the similar code many times.
To solve this problem, you may introduce a [standalone action](structure-controllers.md#standalone-actions)
called [[yii\web\ViewAction]] in a controller. For example,
```php
namespace app\controllers;
use yii\web\Controller;
class SiteController extends Controller
{
public function actions()
{
return [
'page' => [
'class' => 'yii\web\ViewAction',
],
];
}
}
```
Now if you create a view named `about` under the directory `@app/views/site/pages`, you will be able to
display this view by the following URL:
```
http://localhost/index.php?r=site/page&view=about
```
The `GET` parameter `view` tells [[yii\web\ViewAction]] which view is requested. The action will then look
for this view under the directory `@app/views/site/pages`. You may configure [[yii\web\ViewAction::viewPrefix]]
to change the directory for searching these views.
## Best Practices <a name="best-practices"></a>
Views are responsible for presenting models in the format that end users desire. In general, views
* should mainly contain presentational code, such as HTML, and simple PHP code to traverse, format and render data.
* should not contain code that performs DB queries. Such code should be done in models.
* should avoid direct access to request data, such as `$_GET`, `$_POST`. This belongs to controllers.
If request data is needed, they should be pushed into views by controllers.
* may read model properties, but should not modify them.
To make views more manageable, avoid creating views that are too complex or contain too much redundant code.
You may use the following techniques to achieve this goal:
* use [layouts](#layouts) to represent common presentational sections (e.g. page header, footer).
* divide a complicated view into several smaller ones. The smaller views can be rendered and assembled into a bigger
one using the rendering methods that we have described.
* create and use [widgets](structure-widgets.md) as building blocks of views.
* create and use helper classes to transform and format data in views.
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