Bài giảng Web technologies and e-Services - Bài 4, Phần 2: MVC and PHP Frameworks

Web Development

MVC & PHP Frameworks

1

u Everything shoved into one file. L Not Good!

<?

$link = mysql_connect('localhost', 'myuser', 'mypass');

if (!$link) {

die('Could not connect: ' . mysql_error());

}

Typical PHP Code

if($submit) {

$sql = “INSERT INTO my_table (name,address,city,state,zip)

VALUES (”;

$sql .= “’$name’,’$address’,’$city’,’$state’,’$zip’)”;

mysql_query($sql);

} else {

$result = mysql_query(“SELECT * FROM my_table WHERE id = 1”);

$userArray = mysql_fetch_array($result);

} ?>

<html>

<body>

Name: <input type=“text” name=“name”

value=“<?=$userArray[‘name’]?>”><br>

…

</form>

…

2

1

<?

require_once(“config.inc.php");

require_once(“database.inc.php");

$dbh = dbConnect();

if($submit) {

Better but still not great

$sql = “INSERT INTO my_table

(name,address,city,state,zip) VALUES (”;

$sql .= “’$name’,’$address’,’$city’,’$state’,’$zip’)”;

$dbh->query($sql);

} else {

$result = $dbh->query(“SELECT * FROM my_table”);

$userArray = $dbh->fetchRow($result);

}

printHeader();?>

Name: <input type=“text” name=“name”

value=“<?=$userArray[‘name’]?>”><br>

…

</form>

…

3

<? printFooter(); ?>

3

Content

1. Overview of Design Patterns

2. What is MVC architecture?

3. PHP Frameworks

4

2

Patterns in Architecture

u Does this room

makes you feel

happy?

u Why?

–Light (direction)

–Proportions

–Symmetry

–Furniture

–And more…

5

What is a Design Pattern?

A description of a recurrent problem

and of the core of possible solutions.

In Short, a solution

for a typical problem

6

3

Why do we need Patterns?

u Reusing design knowledge

– Problems are not always unique. Reusing

existing experience might be useful.

– Patterns give us hints to “where to look for

problems”.

7

History of Design Patterns

Christopher Alexander

Architecture

1970’

The Timeless Way of Building

A Pattern Language: Towns, Buildings, Construction

Gang of Four (GoF)

Object Oriented

Software Design

Object Oriented

Design Patterns: Elements of

Reusable Object-Oriented Software

1995’

Reusable Object-Oriented Software

Other Areas:

Many Authors

HCI, Organizzationall Behavior,

2007’

Education, Concurent Programming…

GoF: Gamma et al (E. Gamma, R. Helm, R. Johnson, J. Vlissides)

8

4

Content

1. Overview of Design Pattern

2. What is MVC architecture?

3. PHP Frameworks

9

1. What is MVC Architecture?

u MVC is a design structure for separating

representation from presentation using a

subscribe/notify protocol

u The basic idea is to separate

– where and how data (or more generally some

state) is stored, i.e., the model

– from how it is presented, i.e., the views

u Follows basic software engineering

principles:

– Separation of concerns

– Abstraction

10

5

1. What is MVC Architecture? (2)

u MVC consists of three kinds of objects

– Model is the application object

– View is its screen presentation

– Controller defines the way the user interface

reacts to user input

11

1. What is MVC Architecture? (3)

u MVC decouples views and models by

establishing a subscribe/notify protocol

between them

– whenever model changes it notifies the views

that depend on it

– in response each view gets an opportunity to

update itself

u This architecture allows you to attach

multiple views to a model

– it is possible to create new views for a model

without rewriting it

12

6

MVC Architecture in Web

Applications

u Many web frameworks support web

application development based on the

MVC architecture

– Ruby on Rails, Zend Framework for PHP,

CakePHP, Spring Framework for Java, Struts

Framework for Java, Django for Python, …

u MVC architecture has become the

standard way to structure web

applications

13

MVC Framework for Web

Applications

u Model-View-Controller

u Separates:

– M: Data model

– V: Presentation (UI)

– C: Business logic

14

7

MVC Framework for Web

Applications

u Model: Data model which is an abstract

representation of the data stored in the backend

database. Typically uses an object-relational

mapping to map the class structure for the data

model to the tables in the back-send database

u Views: These are responsible for rendering of the

web pages, i.e., how is the data presented in

user’s browser

u Controllers: Controllers are basically event

handlers that process incoming user requests.

Based on a user request, they can update the

data model, and create a new view to be

presented to the user

15

Why use an MVC framework?

uAvoid “reinventing the wheel”

uUse proven, tested code

uAutomation (ORM, generators)

uMaintainability

u“Plugin” functionality

16

8

Flow: Traditional vs. MVC

Query

Processing

Output

Model

Output

Controller

Query

Output

Processing

View

Final Output

17

Content

1. Overview of Design Patterns

2. What is MVC architecture?

3. PHP Frameworks

18

9

3.1. Your own framework

19

3.1. Your own framework (2)

20

10

3.1. Your own framework (2)

21

3.2. Existed PHP Frameworks

u Zend Framework for PHP: http://zend.com

u Symfon y : http://symfony-project.org

u CakePH P : http://cakephp.org

u CodeIgniter: http://codeigniter.com

u Xis c : http://xisc.coom

22

11

Popular PHP MVC Frameworks

u CakePHP

– Documentation is somewhat lacking

– Apparently difficult for beginners

u Symfony

– Great documentation and community

– Easy to get started

u Zend

– Supported by Zend (official PHP company)

– More of a library than complete framework

23

Should you use an existed MVC

framework for your project?

u Are there complex hierarchical

relationships in your data?

u Will this project need to be maintained by

more than one person for more than a

year?

u Do you need the ability to add advanced

features like AJAX without writing the code

from scratch?

u Probably Yes. (unless it’s a throwaway)

– Use a well-established framework with good

documentation and a large community

u But I ask to NOT USE any framework

24

12

Question?

25

13

Bài giảng Web technologies and e-Services - Bài 4, Phần 2: MVC and PHP Frameworks - Nguyễn Bình Minh