introduction to webapps

8/12/2019 Introduction to Webapps

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2 PHP Programming with MySQL

Introduction to Web Development

In 1990 and 1991,Tim Berners-Lee created theWorld Wide Web at the European Laboratory forParticle Physics (CERN) in Geneva, Switzerland

The original purpose of the World Wide Web

(WWW)was to provide easy access to cross-referenced documents that existed on the CERNcomputer network

Hypertextlinkingallows you to quickly openother Web pages


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Introduction to Web Development (cont)

A document on the Web is called a Web page A Web page is identified by a unique address

called the Uniform Resource Locator (URL)

A URL is also commonly referred to as a Webaddress

A URL is a type of Uniform Resource Identifier(URI)

AWeb siterefers to the location on the Internetof the Web pages and related files


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Introduction to Web Development (cont)

Web pages are displayed using a programcalled a Web browser

A Web serveris a computer that delivers Webpages

The most popular Web server software isApache HTTP Server (Apache)

The second most popular Web server is

Microsoft Internet Information Services (IIS) forWindows


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HTML Documents

Web pages are created using Hypertext MarkupLanguage(HTML)

Web pages are commonly referred to as HTMLpagesor documents

A markup languageis a set of characters orsymbols that define a documents logicalstructure

HTML is based on an older language called

Standard Generalized Markup Language(SGML)


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HTML Documents (cont..)

LikeSGML, HTMLwas originally designed as away of defining the elements in a documentindependent of how they would appear

HTMLhas evolved into a language that defines

how elements should appear in a Web browser Understanding HTML is critical in learning how

to write a web application along with the server

programming


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Basic HTML Syntax

HTMLdocumentsare text documents thatcontain formatting instructions called tags

HTML tags include:

Formatting commands (boldfaceor italic)

Controls that allow user input (option buttons or checkboxes)

Tags are enclosed in brackets (< >)and consistof an opening tag and a closing tag

Tutorial for learning HTML

http://www.w3schools.com/html



Web Communication Protocols

A Web page is identified by a unique addresscalled the URL

Each URL consists of two basic parts:

A protocol(usually HTTP) and

Either the domain namefor a Web server or a Webservers Internet Protocol address

Hypertext Transfer Protocol (HTTP) managesthe hypertext links that are used to navigate theWeb



Web Communication Protocols (cont..)

A hostrefers to a computer system that is beingaccessed by a remote computer

A domain nameis a unique address used foridentifying a computer such as a Web server on

the Internet The domain identifieridentifies the type of

institution or organization (.biz, .com, .edu, .org)

An Internet Protocol, or IP address, is another

way to identify computers or devices connectedto the Internet




An IP address consists of a series of four groupsof numbers separated by periods

Each Internet domain name is associated with aunique IP address

HTTP is a component of Transmission ControlProtocol/Internet Protocol (TCP/IP)

Hypertext Transfer Protocol Secure (HTTPS)

provides secure Internet connections fortransactions that require security and privacy




http://www.google.com/help/index.html

Protocol Domain name Directory Filename



Publishing Your Web Site

Web Hosting: The publication of a Web site for public access

Internet access (cable modem, DSL, satellite, dial-upmodem, ISP)

Internet Service Provider(ISP): Provides access to the Internet along with other types

of services such as e-mail



Publishing Your Web Site (cont..)

ISP advantages to hosting a Web site: Extremely fast Internet connections using advanced

fiber-optic connections

Large and powerful Web servers and the expertise

and manpower to maintain and manage them Adomain nameis a unique address used for

identifying a computer, such as a Web server onthe Internet




Domain name registration Pick a domain name that is similar to your business

name or that describes your Web site

You cannot use a domain name that is already in use

or a trademarked name Contact a domain name registrar tofind out the

availability of a domain name and register it

Domain names are stored in a master database that

is maintained by the InterNIC




Domain name registration (continued) For a fee, domain names can be registered for a

specified period of time

Most hosting sites provide registration service for you

After you register your domain name, notify your ISPof your domain information




File Transfer Protocol(FTP) Is a TCP/IP protocolused for transferring files across

the Internet

Transfers files between an FTPclient(your

computer) and an FTP server(a server capable ofrunning FTP)

The vehicle that allows you to get your Web page filesto the Web server




File Transfer Protocol (continued) Your ISP provides a username and password to log

on to the FTP site and upload files to the FTP server

Examples of FTP clients include Firefox and Internet

Explorer and WinScp Use your browser to log on to an FTP server and upload your

files



Cascading Style Sheets

A single piece of CSS formatting information,such as text alignment, is referred to as a style

The term cascadingrefers to the ability for Webpages to use CSS information from more than

one source


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Cascading Style Sheets (continued)

CSS properties: CSS styles are created with two parts separated by a

colon

The propertyrefers to a specific CSS style

The valueassigned to it determines the styles visualcharacteristics

Together, a CSS property and the value assigned to itare referred to as a declarationor style declaration


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Cascading Style Sheets (continued)

Inline Styles Allow you to add style information to a single element

in a document

Internal Style Sheets

Create styles that apply to the entire documentP { color : blue }selector property value

External Style Sheets A separate text document containing style

declarations that are used by multiple documents ona Web site


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Understanding Web Development

Web development, or Web programming, refersto the design of software applications for a Website

The Webmasteris responsible for:

The day-to-day maintenance of a Web site

Monitoring Web site traffic and ensuring that the Websites hardware and software are running properly

Knowledge of Web page design, authoring, and

development


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Client/Server Architecture

Server (back end): A database from which a client requests information

Fulfills a request for information by managing therequest or serving the requested information to the

client Responsible for data storage and management

A system consisting of a client and a server isknown as a two-tier system


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Client/Server Architecture (cont..)

Client (front end): Presents an interface to the user

Gathers information from the user, submits it to aserver, then receives, formats, and presents the

results returned from the server



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(continued)

A three-tier, or multi-tier, client/server systemconsists of three distinct pieces: Client tier, or user interface tier, is the Web browser

Processing tier, or middle tier, handles theinteraction between the Web browser client and the

data storage tier Performs necessary processing or calculations based on the

request from the client tier

Handles the return of any information to the client tier


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Client/Server Architecture (cont..)

Figure 1-16 The design of a three-tier client/server system


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JavaScript and Client-Side Scripting

JavaScriptis: A client-side scripting language that allows Web page

authors to develop interactive Web pages and sites

Used in most Web browsers including Firefox and

Internet Explorer Client-side scriptingis a language that runs on

a local browser (on the client tier) instead of on aWeb server (on the processing tier)

JavaScript and Client Side Scripting


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JavaScript and Client-Side Scripting

(continued)

JavaScript allows you to: Turn static Web pages into applications such as

games or calculators

Change the contents of a Web page after a browser

has rendered it Create visual effects such as animation

Control the Web browser window itself


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Server-Side Scripting and PHP

Server-side scriptingrefers to a scripting language thatis executed from a Web server

Hypertext Preprocessor (PHP)is a server-sidescripting language that is used to develop interactiveWeb sites

Is easy to learn

Includes object-oriented programming capabilities

Supports many types of databases (MySQL, Oracle,Sybase, ODBC-compliant)


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Server-Side Scripting and PHP (cont..)

PHP (continued): PHP is an open sourceprogramming language

Open source refers to software where sourcecode can be freely used and modified

Cant access or manipulate a Web browser likeJavaScript

Exists and executes solely on a Web server, where itperforms various types of processing or accessesdatabases


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Server-Side Scripting and PHP (cont..)

General rule: Use client-side scripting to handleuser interface processing and light processing,

such as validation; use server-side scripting forintensive calculations and data storage

Figure 1-17 How a Web server processes a PHP script


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Introduction to PHP

What is PHP? PHP stands for "PHP Hypertext Preprocessor

An embedded scripting language for HTML like ASPor JSP

A language that combines elements of Perl, C, andJava


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Introduction to PHP

History of PHP Created by Rasmus Lerdorf in 1995 for tracking

access to his resume

Originally a set of Perl scripts known as the Personal

Home Page tools Rewritten in C with database functionality

Added a forms interpreter and released as PHP/FI:includes Perl-like variables, and HTML embedded

syntax


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Introduction to PHP

History of PHP (cont.) Rewritten again in and released as version 2.0 in

November of 1997

Estimated user base in 1997 is several thousand

users and 50,000 web sites served Rewritten again in late 1997 by Andi Gutmans and

Zeev Suraski

More functionality added, database support, protocols

and APIs


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Introduction to PHP

History of PHP (cont.) User base in 1998 estimated 10,000 users and

100,000 web sites installed

Version 3.0 was released in June 1998 as PHP

Estimated user base in tens of thousands andhundreds of thousands of web sites served


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Introduction to PHP

History of PHP (cont.) Rewritten again in 1997 by Andi Gutmans and Zeev

Suraski

More functionality added (OOP features), database

support, protocols and APIs PHP 3.0 is released in June 1998 with some OO

capability

The core is rewritten in 1998 for improved

performance of complex applications


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Introduction

History of PHP (cont.) The core is rewritten in 1998 by Zeev and Andi and

dubbed the Zend Engine

The engine is introduced in mid 1999 and is released

with version 4.0 in May of 2000 The estimated user base is hundreds of thousands of

developers and several million of web sites served


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Introduction

History of PHP (cont.)

Version 5.0 will include version 2.0 of the ZendEngine

New object model is more powerful and intuitive

Objects will no longer be passed by value; they now will bepassed by reference

Increases performance and makes OOP more attractive


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PHP Language Basics

The Script Tags

All PHP code is contained in one of several scripttags:


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PHP Language Basics

The Script Tags (cont.)

ASP-style tags Introduced in 3.0; may be removed in the future


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PHP Language Basics

The Script Tags (cont.)

Echo Tags

Name:

Address:


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PHP Language Basics

Hello World!: An Example

Like Perl, there is more than one way to do it

PHP L B i


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PHP Language Basics

Hello World!: An Example (cont.)

PHP L B i


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PHP Language Basics

Constants, Data Types and Variables

Constants define a string or numeric value

Constants do not begin with a dollar sign

Examples:

define(COMPANY, Acme Enterprises); define(YELLOW, #FFFF00);

define(PI, 3.14);

define(NL,
\n);

PHP L B i


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PHP Language Basics


Using a constant print(Company name: . COMPANY . NL);

PHP L B i


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PHP Language Basics


Data types Integers, doubles and strings

isValid = true; // Boolean

25 // Integer

3.14 // Double

Four // String

Total value // Another string

PHP L B i


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PHP Language Basics


Data types Strings and type conversion

$street = 123;

$street = $street . Main Street;

$city = Naperville;$state = IL;

$address = $street;

$address = $address . NL . $city, $state;

$number = $address + 1; // $number equals 124

PHP L B i


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PHP Language Basics


Data types Arrays

Perl-like syntax

$arr = array("foo" => "bar", 12 => true);

same as

$arr[foo] = bar;

$arr[12] = true;

PHP L B i


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PHP Language Basics

Constants, Data Types and Variables Arrays (cont.)

PHP L B i


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PHP Language Basics


Objects Currently not much more advanced than than associative

arrays Using constants

Before version 5.0, objects are passed by value

Slow Functions can not easily change object variables

PHP L B i


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PHP Language Basics


Operators Contains all of the operators like in C and Perl (even the

ternary)

Statements

if, if/elseif

Switch/case

for, while, and do/while loops

Include and require statements for code reuse


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B ilt i F ti


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Built-in Functions

What comes In the box?

Directory Functions Platform independent

Error Handling Functions Recover from warnings and errors

Filesystem Functions Access flat files

Check directory, link, and file status information

Copy, delete, and rename files

B ilt in F nctions


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Built-in Functions


IMAP Functions Manipulate mail boxes via the IMAP protocol

LDAP Functions Works with most LDAP servers

Mail Functions mail($recipient, $subject, $message)

Built in Functions


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Built-in Functions


Database Functions dba: dbm-style abstraction layer

dBase

Frontbase

Informix

Ingres II

Interbase

mSQL

Built in Functions


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Built-in Functions


Database Functions (cont.) MySQL

Oracle

PostgreSQL

SQL Server

MING Macromedia Flash

PDF Create/manipulate PDF files dynamically

Built in Functions


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Built-in Functions


POSIX Functions Manipulate process information

Regular Expression Functions Uses POSIX regex

Semaphore and Socket Functions Available only on Unix

Session Management Functions

Summary


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Summary

In 1990 and 1991,Tim Berners-Lee created theWorld Wide Web at the European Laboratory forParticle Physics (CERN)

Transmission Control Protocol/Internet Protocol

(TCP/IP) is a large collection of communicationprotocols used on the Internet

A Document Type Definition (DTD) defines theelements and attributes that can be used in adocument

Summary (cont )


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Summary (cont..)

Cascading Style Sheets (CSS) are a standardset by the W3C for managing the design andformatting of Web pages in a Web browser

A system that consists of a client and a server is

known as a two-tier system A three-tier client/server system consists of the

client tier, the processing tier, and the datastorage tier

Summary (cont )


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Summary (cont..)

JavaScript is a client-side scripting language thatallows Web page authors to develop interactiveWeb pages and sites

Hypertext Preprocessor (PHP) is a server-side

scripting language that is used for developinginteractive Web sites

Open source refers to software for which thesource code can be freely used and modified


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