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Testdriving with Yii

In this section, we describe how to create a skeleton application that will serve as our starting point. For simplicity, we assume that the document root of our Web server is /wwwroot and the corresponding URL is http://www.example.com/.

1. Installing Yii

We first install the Yii framework. Grab a copy of the Yii release file (version 1.0.3 or above) from www.yiiframework.com and unpack it to the directory /wwwroot/yii. Double check to make sure that there is a directory /wwwroot/yii/framework.

Tip: The Yii framework can be installed anywhere in the file system. Its framework directory contains all framework code and is the only directory needed when deploying an Yii application. A single installation of Yii can be used by multiple Yii applications.

After installing Yii, open a browser window and access the URL http://www.example.com/yii/requirements/index.php. It shows the requirement checker provided in the Yii release. Make sure our Web server and PHP installation reaches the minimal requirement by Yii. In particular, we should enable both the pdo and pdo_sqlite PHP extensions which are required by our blog application to access the SQLite database.

2. Creating Skeleton Application

We then use the yiic tool to create a skeleton application under the directory /wwwroot/blog. The yiic tool is a command line tool provided in the Yii release. It can be used to generate code for certain tasks.

Open a command window and execute the following command:

% /wwwroot/yii/framework/yiic webapp /wwwroot/blog
Create a Web application under '/wwwroot/blog'? [Yes|No]y

Tip: In order to use the yiic tool as shown above, the CLI PHP program must be on the command search path. If not, the following command may be used instead:

path/to/php /wwwroot/yii/framework/yiic.php webapp /wwwroot/blog

To try out the application we just created, open a Web browser and navigate to the URL http://www.example.com/blog/index.php. We shall see that our application has three fully functional pages: the homepage, the contact page and the login page.

In the following, we briefly describe what we have in this skeleton application.

Entry Script

We have an entry script file /wwwroot/blog/index.php which has the following content:

// remove the following line when in production mode
defined('YII_DEBUG') or define('YII_DEBUG',true);

This is the only script that Web users can directly access. The script first includes the Yii bootstrap file yii.php. It then creates an application instance with the specified configuration and executes the application.

Base Application Directory

We also have an application base directory /wwwroot/blog/protected. The majority of our code and data will be placed under this directory, and it should be protected from being accessed by Web users. For Apache httpd Web server, we place under this directory a .htaccess file with the following content:

deny from all

For other Web servers, please refer to the corresponding manual on how to protect a directory from being accessed by Web users.

3. Application Workflow

To help understand how Yii works, we describe the main workflow in our skeleton application when a user is accessing its contact page:

  1. The entry script is executed by the Web server to process the request;
  2. An application instance is created and configured with initial property values specified in the application configuration file /wwwroot/blog/protected/config/main.php;
  3. The application resolves the request into a controller and a controller action. For the contact page request, it is resolved as the site controller and the contact action;
  4. The application creates the site controller in terms of a SiteController instance and then executes it;
  5. The SiteController instance executes the contact action by calling its actionContact() method;
  6. The actionContact method renders a view named contact to the Web user. Internally, this is achieved by including the view file /wwwroot/blog/protected/views/site/contact.php and embedding the result into the layout file /wwwroot/blog/protected/views/layouts/main.php.