Download Client/Server Design in Web Applications

Chapter 2
Client/Server Applications
954240 Web Programming
Modern Management and Information Technology
College of Arts, Media and Technology, Chiang Mai University
Contents
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Client/Server Design in Web Applications
Working with Files and Folders
What Languages Will I Use?
What Software Will I Need?
Client/Server Design in Web Applications
Client/Server Design in Web Applications
Recall from Chapter 1:
• a client application provides an interface to the user
and waits for the user to request some action
• a client application calls a server application to process
the request
• a server application sends back a response
• a client application receives the response and present
to the user
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Client/Server Design in Web Applications
Example of client/server design
Source: Mike O’Kane (2011) A Web-Based Introduction to Programming
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Client/Server Design in Web Applications
Recall from Chapter 1:
• A single server can deliver the same services to
any number of clients.
• Changes can be made on the server with no need
to make changes on the client (ex. update
software on the server, not on every clients)
• A Web application is an example of an Internetbased client/server design
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Client/Server Design in Web Applications
• To develop a Web-based applications:
- We must create files that contain the
instructions for our Web pages and store them
on a Web server.
- Then, the server can response to the
requests.
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Working with Files and Folders
Working with Files and Folders
In this course you will use different extensions
for your files:
• Plain text files
• HTML files
• PHP files
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Working with Files and Folders
• Plain text files
- Using a .txt or .dat extension
- Used to store simple data
- Ex. you might create a file named “scores.txt”
that contains a list of student scores.
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Working with Files and Folders
• HTML files
- Using a .html extension
- Used to store the markup instructions to allow
the user to enter information
- Ex. you might create a file named “wages.html“
that contains a Web page with a form for the user
to submit their hours worked and hourly wage.
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Working with Files and Folders
• PHP files
- Using a .php extension
- Used to store the source code. PHP programs will
receive information from the user or look up data in
files to process operations and generate output.
- Ex, you might create a file named “wages.php” that
contains the source code to receive information, then
calculate and display the pay.
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Working with Files and Folders
• Files are usually organized into folders for ease
of management
• You can access files on disks located in local
drives (in your personal computer)
• You can also access files on disks in remote
disk drives, (in other computers => server)
through a network such as the Internet
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Working with Files and Folders
• However, in this course, we will use a software
that allows you to run a Web server on your
local computer with no need for Internet
access in order to work simply and securely
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What Languages Will I Use?
What Languages Will I Use?
You will write your Web programs using a
combination of two languages:
• HTML (Hypertext Markup Language)
• PHP (PHP Hypertext Preprocessor)
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What Languages Will I Use?
• HTML (Hypertext Markup Language)
- Provides the markup instructions that you will use to
create and format the Web pages that display the user
interface for your Web applications
- You will use HTML to display headings, paragraphs,
forms, tables, buttons, and images
- Everything you learn will be based on current HTML
standards, which is known as XHTML
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What Languages Will I Use?
• PHP (PHP Hypertext Preprocessor)
PHP is a programming language that you will use
to write server-based program that process user
requests by:
- performing calculations - reading data from files/databases
- validating input
- writing output to files/databases
- making decisions
- returning results to the user, etc.
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What Languages Will I Use?
From an example of a simple client/server application
from Chapter 1, there are two web pages:
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Source: Mike O’Kane (2011) A Web-Based Introduction to Programming
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What Languages Will I Use?
• The first Web page is generated from HTML
code located in an .html file on a Web server
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A form that the user can
enter information (input)
and click a button
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What Languages Will I Use?
• When the user click the button, the browser
sends the input (10.75 and 25) back to the
server with a request to process a PHP code file
• The PHP file receives input, calculates a wage
based on the input, and generates a new HTML
page to display the results (The second page)
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What Languages Will I Use?
• The second Web page is created by the PHP file
and the server returns this to the Web browser
for display to the user
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What Languages Will I Use?
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What Software Will I Need?
What Software Will I Need?
• A text editor to create HTML and PHP files.
• A Web browser to submit requests to the Web
server and display the result Web pages
• A Web server that can process requests
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