upgrading instructions WIP

docs/guide/index.md

@@ -27,4 +27,4 @@
 * [Performance Tuning](performance.md)
 * [Testing](testing.md)
 * [Automatic Code Generation](gii.md)
-* [Upgrading from 1.1 to 2.0](upgrade.md)
+* [Upgrading from 1.1 to 2.0](upgrade-from-v1.md)

docs/guide/upgrade-from-v1.md

+Upgrading from Yii 1.1
+======================
+
+In this chapter, we list the major changes introduced in Yii 2.0 since version 1.1.
+We hope this list will make it easier for you to upgrade from Yii 1.1 and quickly
+master Yii 2.0 based on your existing Yii knowledge.
+
+
+Component and Object
+--------------------
+
+Yii 2.0 breaks the `CComponent` class in 1.1 into two classes: `Object` and `Component`.
+The `Object` class is a lightweight base class that allows defining class properties
+via getters and setters. The `Component` class extends from `Object` and supports
+the event feature and the behavior feature.
+
+If your class does not need the event or behavior feature, you should consider using
+`Object` as the based class. This is usually the case for classes that represent basic
+data structures.
+
+
+Object Configuration
+--------------------
+
+The `Object` class introduces a convention for configuring objects. In general, any
+descendant class of `Object` should follow this convention when declaring a constructor:
+
+~~~
+class MyClass extends \yii\Object
+{
+    public function __construct($param1, $param2, $config = array())
+    {
+        // ...
+        parent::__construct($config);
+    }
+
+    public function init()
+    {
+        parent::init();
+        // ... at this point, all configurations have been applied ...
+    }
+}
+~~~
+
+In descendant classes, you can override the `init()` method to do initialization work
+that should be done after all configurations are applied.
+
+By following this convention, you will be able to use the powerful object creation method via:
+
+~~~
+$object = Yii::createObject(array(
+    'class' => 'MyClass',
+    'property1' => 'abc',
+    'property2' => 'cde',
+), $param1, $param2);
+~~~
+
+
+Events
+------
+
+There is no longer the need to define an `on`-method in order to define an event in Yii 2.0.
+Instead, you can use whatever event names. To attach a handler to an event, you should
+use the `on` method now:
+
+~~~
+$component->on($eventName, $handler);
+// To detach the handler, use:
+// $component->off($eventName, $handler);
+~~~
+
+When you attach a handler, you can now associate it with some parameters which can be later
+accessed via the event parameter by the handler:
+
+~~~
+$component->on($eventName, $handler, $params);
+~~~
+
+Because of this change, you can now use "global" events. Simply trigger and attach handlers to
+an event of the application instance:
+
+~~~
+Yii::$app->on($eventName, $handler);
+....
+// this will trigger the event and cause $handler to be invoked.
+Yii::$app->trigger($eventName);
+~~~
+
+
+View
+----
+
+Yii 2.0 introduces a `View` class to represent the view part in the MVC pattern.
+It can be configured globally through the "view" application component. It is also
+accessible in any view file via `$this`. This is one of the biggest changes compared to 1.1:
+**`$this` in a view file no longer refers to the controller or widget object.**
+It refers to the view object that is used to render the view file. To access the controller
+or the widget object, you have to use `$this->context` now.
+
+Because you can access the view object through the "view" application component,
+you can now render a view file like the following anywhere in your code, not necessarily
+in controllers or widgets:
+
+~~~
+$content = Yii::$app->view->renderFile($viewFile, $params);
+// You can also explicitly create a new View instance to do the rendering
+// $view = new View;
+// $view->renderFile($viewFile, $params);
+~~~
+
+Also, there is no more `CClientScript` in Yii 2.0. The `View` class has taken over its role
+with significant improvements. For more details, please see the "assets" subsection.
+
+TBD: built-in renderers
+
+Models
+------
+
+Controllers
+-----------
+
+Themes
+------
+
+Console Applications
+--------------------
+
+I18N
+----
+
+Behaviors
+---------
+
+TBD
+
+Action filters are replaced by behaviors (`ActiionFilter`).
+
+
+Assets
+------
+
+Static Helpers
+--------------
+
+`ActiveForm`
+------------
+
+
+Query Builder
+-------------
+
+
+ActiveRecord
+------------
+
+User and Identity
+-----------------
+
+URL Management
+--------------
+
+Response
+--------
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