You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
52 lines
2.8 KiB
52 lines
2.8 KiB
12 years ago
|
MVC Overview
|
||
|
|
============
|
||
|
|
|
||
|
|
Yii implements the model-view-controller (MVC) design pattern, which is
|
||
|
|
widely adopted in Web programming. MVC aims to separate business logic from
|
||
|
|
user interface considerations, so that developers can more easily change
|
||
|
|
each part without affecting the other. In MVC, the model represents the
|
||
|
|
information (the data) and the business rules; the view contains elements
|
||
|
|
of the user interface such as text, form inputs; and the controller manages
|
||
|
|
the communication between the model and the view.
|
||
|
|
|
||
|
|
Besides implementing MVC, Yii also introduces a front-controller, called
|
||
|
|
`Application`, which encapsulates the execution context for the processing
|
||
|
|
of a request. Application collects some information about a user request and
|
||
|
|
then dispatches it to an appropriate controller for further handling.
|
||
|
|
|
||
|
|
The following diagram shows the static structure of a Yii application:
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
A Typical Workflow
|
||
|
|
------------------
|
||
|
|
The following diagram shows a typical workflow of a Yii application when
|
||
|
|
it is handling a user request:
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
1. A user makes a request with the URL `http://www.example.com/index.php?r=post/show&id=1`
|
||
|
|
and the Web server handles the request by executing the bootstrap script `index.php`.
|
||
|
|
2. The bootstrap script creates an [Application](/doc/guide/basics.application)
|
||
|
|
instance and runs it.
|
||
|
|
3. The Application obtains detailed user request information from
|
||
|
|
an [application component](/doc/guide/basics.application#application-component)
|
||
|
|
named `request`.
|
||
|
|
4. The application determines the requested [controller](/doc/guide/basics.controller)
|
||
|
|
and [action](/doc/guide/basics.controller#action) with the help
|
||
|
|
of an application component named `urlManager`. For this example, the controller
|
||
|
|
is `post`, which refers to the `PostController` class; and the action is `show`,
|
||
|
|
whose actual meaning is determined by the controller.
|
||
|
|
5. The application creates an instance of the requested controller
|
||
|
|
to further handle the user request. The controller determines that the action
|
||
|
|
`show` refers to a method named `actionShow` in the controller class. It then
|
||
|
|
creates and executes filters (e.g. access control, benchmarking) associated
|
||
|
|
with this action. The action is executed if it is allowed by the filters.
|
||
|
|
6. The action reads a `Post` [model](/doc/guide/basics.model) whose ID is `1` from the database.
|
||
|
|
7. The action renders a [view](/doc/guide/basics.view) named `show` with the `Post` model.
|
||
|
|
8. The view reads and displays the attributes of the `Post` model.
|
||
|
|
9. The view executes some [widgets](/doc/guide/basics.view#widget).
|
||
|
|
10. The view rendering result is embedded in a [layout](/doc/guide/basics.view#layout).
|
||
|
|
11. The action completes the view rendering and displays the result to the user.
|