Get things done with Yii - quickly build webapplications

GET THINGS DONE WITH

QUICKLY BUILD A WEBAPP USING YII

GIULIANO IACOBELLI - @Giuliano84 - me@giulianoiacobelli.com

USUALLY EVERYTHING STARTS
FROM AN IDEA

IF IT’S THE RIGHT ONE
AND IS WELL EXECUTED..

IF YOU HAVE GOOD IDEA, DO IT.
MOVE FAST AND
BREAK THINGS

WHAT IS IT?

Yii is a high-performance component-based
PHP framework for developing large-scale
Webapplications. It enables maximum
reusability in Web programming and can
signiﬁcantly accelerate the development
process.

IT’S EASY?
IT’S RAPID?
IT’S SECURE?

YES IT IS (YII) !!!

THE MVC PATTERN
MVC is a design pattern
widely adopted in Web
programming that aims to
separate business logic from
user interface
considerations, so that
developers can more easily
change each part without
affecting the other.

THE MVC PATTERN
Assume a Web application consists of several sub-
applications:

• Front end: a public-facing website for normal end users;
• Back end: a website that exposes administrative
functionality for managing the application.
• Console: an application consisting of console commands
to be run in a terminal window or as scheduled jobs to
support the whole application;
• Web API: providing interfaces to third parties for
integrating with the application.

M for MODEL
Models are used to keep data and their relevant business rules. A
model represents a single data object that could be a row in a
database table or a form of user inputs.

• should contain properties to represent specific data;
• should contain business logic (e.g. validation rules) to ensure
the represented data fulfills the design requirement;
• may contain code for manipulating data. For example, a
SearchForm model, besides representing the search input data,
may contain a search method to implement the actual search.

C for CONTROLLER

Controllers are the glue that binds models, views and other
components together into a runnable application. They are
responsible for dealing directly with end user requests.

• may access $_GET, $_POST and other PHP variables that
represent user requests;
• may create model instances and manage their life cycles.
• should avoid containing embedded SQL statements, which are
better kept in models.
• should avoid containing any HTML or any other presentational
markup. This is better kept in views.

V for VIEW

A view is a PHP script consisting of mainly elements of user interface
the spirit of seperation of logic and presentation, large chunk of logic
should be placed in controller or model instead of view.

• should mainly contain presentational code, such as HTML, and
simple PHP code to traverse, format and render data;
• should avoid containing code that performs explicit DB queries.
Such code is better placed in models.
• should avoid direct access to $_GET, $_POST, or other similar
variables that represent the end user request. This is the
controller's job.

THE ENTRY SCRIPT
This is a “bootstrap” file, meaning that all user interactions actually
go through it. For example, showing an employee record might be
through the URL. It is the only PHP script that end users can directly
request to execute.

// remove the following line when in production mode
defined('YII_DEBUG') or define('YII_DEBUG',true);
// include Yii bootstrap file
require_once('path/to/yii/framework/yii.php');
// create application instance and run
$configFile='path/to/config/file.php';
Yii::createWebApplication($configFile)->run();

YII WORKFLOW
1 - Request with the URL
http://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 instance and runs it.

3 - The Application obtains detailed user
request information from an application
component named request.

4 - The application determines the requested
controller and action with the help of an
application component named urlManager.

YII WORKFLOW
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.

6 - The action reads a Post model whose ID is
1 from the database.

7 - The action renders a view named show
with the Post model.

8 - The view reads and displays the attributes
of the Post model.

9,10,11 - The view executes some widgets,
embed the rendering result in a layout and
displays it to the user.

OK, OK, I GOT IT, TOO MUCH TALK..

LET’S HAVE AN IDEA TO BUILD..

A BLOG!
OK, IT’S NOT THAT AMAZING BUT IN THIS
WAY I’M PRETTY SURE THAT ALL OF YOU
KNOW WHAT WE ARE GOIN TO BUILD

WARM UP

• CREATE A “BLOGDEMO” FOLDER
IN YOUR APACHE DOCUMENT
ROOT DIRECTORY
• DOWNLOAD YiiBlogDemo.zip FILE
FROM http://goo.gl/nOqef AND
UNZIP IT
• OPEN FRAMEWORK.ZIP AND
PLACE ITS CONTENT IN YOUR
“BLOGDEMO” FOLDER

YII PREPARATION

Run a simple console command
“blogdemo/framework/yiic webapp ../“

to generate a skeleton Web application built with Yii.
This will create a skeleton Yii application under the
directory WebRoot/testdrive.

THE WEB APPLICATION

The application is fully functional, with nice features
including user login and contact form. It is a good starting
point for implementing more sophisticated features.

WHAT A BLOG USUALLY HAVE?

• POSTS
• USERS
• COMMENTS
• TAGS

SETTING UP THE DATABASE
return array(
......
'components'=>array(
......
'db'=>array(
'connectionString' => 'mysql:host=localhost;dbname=blog',
'emulatePrepare' => true,
'username' => 'root',
'password' => '',
'charset' => 'utf8',
'tablePrefix' => 'tbl_',
),
),
......
);

GENERATING THE MODELS
We need to create a model class for each of our database
tables. Yii has an amazing component called Gii that totally
automates this process (known as scaffolding) for us.

'modules'=>array(
'gii'=>array(
'class'=>'system.gii.GiiModule',
'password'=>'pick up a password here',
),
),

OUR MODELS
• User.php contains the User class and can be used to access
the tbl_user database table;
• Post.php contains the Post class and can be used to access
the tbl_post database table;
• Tag.php contains the Tag class and can be used to access the
tbl_tag database table;
• Comment.php contains the Comment class and can be used
to access the tbl_comment database table;
• Lookup.php contains the Lookup class and can be used to
access the tbl_lookup database table.

CRUD OPERATIONS
After the model classes are created, we can use the Crud
Generator to generate the code implementing the CRUD
operations for these models. We will do this for the Post
and Comment models.

AUTHENTICATING USER

Our blog application needs to differentiate between
the system owner and guest users. Therefore, we need
to implement the user authentication feature
User authentication is performed in a class
implementing the IUserIdentity interface. The skeleton
application uses the UserIdentity class for this
purpose.

The class is stored in the file /wwwroot/blogdemo/
protected/components/UserIdentity.php.

AUTHENTICATING USER

Application already provides user authentication
by checking if the username and password are
both demo or admin.
Now we will modify the corresponding code so
that the authentication is done against the User
database table.

EDITING USERIDENTITY.PHP
public function authenticate()
{
$username=strtolower($this->username);
$user=User::model()->find('LOWER(username)=?',array($username));
if($user===null)
$this->errorCode=self::ERROR_USERNAME_INVALID;
else if(!$user->validatePassword($this->password))
$this->errorCode=self::ERROR_PASSWORD_INVALID;
else
{
$this->_id=$user->id;
$this->username=$user->username;
$this->errorCode=self::ERROR_NONE;
}
return $this->errorCode==self::ERROR_NONE;
}

public function getId()
{
return $this->_id;
}

RECAP
• Identified the requirements to be fulfilled;
• We installed the Yii framework and created a skeleton
application;
• We designed and created the blog database;
• We generated basic CRUD operations;
• We modified the authentication method to check
against the tbl_user table.

CUSTOMIZING POST MODEL
Post model generated is fine but now we need to specify
validation rules and related objects
• Validation rules ensure the attribute values entered by
users are correct before they are saved to the database.
For example, the status attribute of Post should be an
integer 1, 2 or 3.
• Customizing the relations we can exploit the powerful
Relational ActiveRecord (RAR) feature to access the
related object information of a post, such as its author
and comments, without the need to write complex SQL
statements.

VALIDATION RULES
Based on the requirement analysis, we modify the
rules() method as follows:

public function rules()
{
return array(
array('title, content, status', 'required'),
array('title', 'length', 'max'=>128),
array('status', 'in', 'range'=>array(1,2,3)),
array('tags', 'match', 'pattern'=>'/^[ws,]+$/',
'message'=>'Tags can only contain word characters.'),
array('tags', 'normalizeTags'),

array('title, status', 'safe', 'on'=>'search'),
);
}

MODEL RELATIONS
We customize relations() method as follow
public function relations()
{
return array(
'author' => array(self::BELONGS_TO, 'User', 'author_id'),
'comments' => array(self::HAS_MANY, 'Comment', 'post_id',
'condition'=>'comments.status='.Comment::STATUS_APPROVED,
'order'=>'comments.create_time DESC'),
'commentCount' => array(self::STAT, 'Comment', 'post_id',
'condition'=>'status='.Comment::STATUS_APPROVED),
);
}

We also introduce in the Comment class Comment extends CActiveRecord
{
model class two constants that are const STATUS_PENDING=1;
used in the above method: const STATUS_APPROVED=2;
......
}

REPRESENTING STATUS IN TEXT

Because the status of a post is stored as an integer in the
database, we need to provide a textual representation so that it
is more intuitive when being displayed to end users. In a large
system, the similar requirement is very common.
As a generic solution, we use the tbl_lookup table to store the
mapping between integer values and textual representations
that are needed by other data objects.

We modify the Lookup model class as follows to more easily
access the textual data in the table.

LOOKUP.PHP
class Lookup extends CActiveRecord
{
private static $_items=array();
public static function items($type)
{
if(!isset(self::$_items[$type]))
self::loadItems($type);
return self::$_items[$type];
}

public static function item($type,$code)
{
if(!isset(self::$_items[$type]))
self::loadItems($type);
return isset(self::$_items[$type][$code]) ? self::$_items[$type][$code] : false;
}

private static function loadItems($type)
{
self::$_items[$type]=array();
$models=self::model()->findAll(array(
'condition'=>'type=:type',
'params'=>array(':type'=>$type),
'order'=>'position',
));
foreach($models as $model)
self::$_items[$type][$model->code]=$model->name;
}
}

POST POSSIBLE STATUSES

class Post extends CActiveRecord
{
const STATUS_DRAFT=1;
const STATUS_PUBLISHED=2;
const STATUS_ARCHIVED=3;
......
}

Now we can call Lookup::items('PostStatus') to get the
list of possible post statuses (text strings indexed by the
corresponding integer values), and call
Lookup::item('PostStatus', Post::STATUS_PUBLISHED) to
get the string representation of the published status.

CONFIGURING ACCESS RULES
public function accessRules()
{
return array(
array('allow', // allow all users to perform 'list' and 'show'
actions
'actions'=>array('index', 'view'),
'users'=>array('*'),
),
array('allow', // allow authenticated users to perform any action
'users'=>array('@'),
),
array('deny', // deny all users
'users'=>array('*'),
),
);
}

The rules state that all users can access the index and
view actions, and authenticated users can access any
actions, including the admin action.

CREATE AND UPDATE
The create and update operations are very similar. They both
need to display an HTML form to collect user inputs, validate
them, and save them into database.
Gii generates a partial view /wwwroot/blog/protected/views/
post/_form.php that is embedded in both the create and update
views to render the needed HTML form.
We want to add a dropdown list to collect user input for STATUS
attribute

echo $form->dropDownList($model,'status',Lookup::items('PostStatus'));

CREATE AND UPDATE
We then modify the Post class so that it can automatically set
some attributes (create_time, author_id) before a post is
saved to the database. We override the beforeSave() method
as follows
protected function beforeSave() {
if(parent::beforeSave())
{
if($this->isNewRecord)
{
$this->create_time=$this->update_time=time();
$this->author_id=Yii::app()->user->id;
}
else
$this->update_time=time();
return true;
}
else
return false;
}

HOW TO BORROW SOME STYLE?

http://twitter.github.com/bootstrap

LOOK AT THE NUMBERS

http://www.phonecount.com/pc/count.jsp

BOOTSTRAP RESPONSIVENESS
It supports a handful of media queries in a single file to
help make your projects appropriate on different devices
and screen resolutions.

@media (min-width:400px) { }

Thanks

Giuliano Iacobelli
giuliano.iacobelli
me@giulianoiacobelli.com
http://giulianoiacobelli.com

Connect with me:

Ps: slide 47 and 48 were borrowed from this amazing presentation of Brad Frost

Get things done with Yii - quickly build webapplications

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (20)

En vedette

En vedette (13)

Similaire à Get things done with Yii - quickly build webapplications

Similaire à Get things done with Yii - quickly build webapplications (20)

Plus de Giuliano Iacobelli

Plus de Giuliano Iacobelli (14)

Dernier

Dernier (20)

Get things done with Yii - quickly build webapplications