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![Page 1: Web Programming Introduction to PHP COM427 1. Objectives To understand what PHP is and how a PHP script works with a Web Browser and a Web Server To learn.](https://reader036.fdocuments.in/reader036/viewer/2022062314/56649d9c5503460f94a85cad/html5/thumbnails/1.jpg)
Web Programming
Introduction to PHP
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Objectives
• To understand what PHP is and how a PHP script works with a Web Browser and a Web Server
• To learn what software and components you need to get started with PHP
• To create and run a simple PHP script
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Web servers
• Can be considered at two levels:1. The physical computer that stores web files and web application
programs.2. More precisely, the web server is a specialized piece of software,
running on the server computer, which• receives requests, via the Internet, for web pages or programs• retrieves the pages / executes the programs• returns the results over the Internet to the browser.
• Common web servers:– Apache– Microsoft Internet Information Services (IIS)
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Web Application Program
• Carries out many dynamic tasks, such as the following: – Input a search term, search the WWW, and
return the results– Calculate and display the number of times that a
page has been viewed– Verify the input fields on a Web form– Save a Web form into a database– Display a special graph, or return the results of a
calculation based on data input from a form
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What is PHP?
• Original of PHP (Rasmus Lerdorf) [born in Qeqertarsuaq, Greenland]
• Server side – e.g. form handling, database access– (as opposed to Javascript which is
mainly clientside)• (X)HTML-embedded scripting language
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Basic Browser Web Server interaction
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1. Browser in Client sents http request e.g. http://localhost/~labuser/test.php
2. Server receives request and activates php to interpret php program (test.php)
3. Server sends html output to browser in client for display
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PHP Advantages
Advantages of Using PHP to enhance Web pages:
– Easy to use.– Open source.– Multiple platform.
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Browser PHP MySQL Interaction
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A third layer can be added if php makes a call to a database to supply data in response to web browser request
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Browser/PHP/database example
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Browser holds html form
Enter Details of Car
Reg Num
Make
Submit
PHP program- Receives values- Plugs them into database
query- Sends Request to database- Receives data and - Returns result as web page
Details of Car
Taxed ? YesMOT? YesReg Date: 1st Jan 2010
https://www.gov.uk/check-vehicle-tax
Car Database
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PHP & Javascript
• Javascript– Client side– Good for form validation– Good for web page presentation– Poor for security– Some database access
• PHP– Server side– Better security– Good database access
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Getting Started with PHP
To develop and publish PHP scripts all you need is:
– A Web server with PHP built into it– A client machine with a basic text editor and Internet
connection– FTP software (if webserver used) Use localhost in the development phase and then
upload to the server
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Installation of Apache, PHP and MySQL
• In the lab: Apache server, PHP, MySQL installed
• At home: – Install Apache, PHP and MySQL separately, – Or install Apache, PHP, MySQL together using a
package, eg. WAMP or MAMP (for Windows or Mac)
– XAMPP installs very easily & is cross-platform (Windows or Mac)
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Install Apache, PHP & MySQL• Download XAMPP
http://sourceforge.net/projects/xampp
Installs Apache/PHP/MySQL (plus PERL)
Cross platform (Mac/Windows/Linux)
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Using Apache, PHP and MySQL• iMAC Lab
– Save your HTML file (e.g. test.html) or PHP file (e.g. myprog.php) under: Macintosh ID/Users/Labuser/Sites
– Run html or php file under Apache using: e.g. http://localhost/~labuser/test.html OR create subdirectory starting with b (e.g. student number
b00XXXXXX ) http://localhost/~labuser/b00XXXXXXClick on file in browser window
• Windows Lab/ Own Windows Machine[ Put files in C://xampp/htdocs e.g. hello.php URL to run file http://localhost/hello.php OR create subdirectory and click on browser list]
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Using MySQL
– http://localhost/phpMyAdmin MAC Lab Login (MySQL)
Login: labuser Password: macimd15
Windows Lab login (MySQL)Login: labuserPassword: Labuser1
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Creating a PHP Script File
You can use a number of different editors to create your PHP script files.
• TextWrangler (can add line numbers)• Save file with .php extension
[In Windows Lab can use Notepad++ to create PHP scripts]
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Working with HTML
• Use tags <?php // opening php tag
?> // closing php tag
Save the file with .php extension
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Accessing Your File Using a Browser
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You should use this URL in the iMac LAB:
• for html files: http://localhost/~labuser/page1.html
• for php files: http://localhost/~labuser/ex1.php
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Print Statement Syntax
• The print statement syntax:
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print ( "Your message to print" );
Enclose messagein quotation
marks
Message to Output
End in asemi-colon
Parenthesis areoptional
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Echo Statement Syntax
• The echo statement syntax:
echo "the message to print";
Echo almost identical to print
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If Use Improper Syntax
• Suppose you use the wrong syntax: 1. <?php2. print "A simple initial script;
3. ?>
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Missing inverted commas
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A Little About PHP's Syntax
• Some PHP Syntax Issues: – Be careful to use quotation marks, parentheses, and brackets in
pairs. – Most PHP commands end with a semicolon (;).– Be careful of case.
– PHP ignores blank spaces.
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Embedding PHP Statements Within HTML Documents
• One way to use PHP is to embed PHP scripts within HTML tags in an HTML document. (prog1.php)
1. <html>2. <head> 3. <title>HTML With PHP Embedded</title> </head>4. <body> 5. <font size=5 color="blue">Welcome To My Page</font>6. <?php7. print "<br /> Using PHP gets easier as you keep practising it<br />";8. ?>9. </body></html>
(PHP code alone will run fine since system will construct an html output for browser automatically)
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Using Backslash (\) to Generate HTML Tags with print()
• Sometimes you want to output an HTML tag that also requires double quotation marks. – Use the backslash ("\") character to signal that the double
quotation marks themselves should beoutput:print "<font color=\"blue\">";
– The above statement would output: <font color="blue">
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Using Comments with PHP Scripts
• Comments enable you to include descriptive text along with the PHP script.– Comment lines are ignored when the script
runs; they do not slow down the run-time.– Comments have two common uses.
• Describe the overall script purpose.• Describe particularly tricky script lines.
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Using Comments with PHP Scripts
• Comment Syntax - Use //<?php// This is a comment?>
• Can place on Same line as a statement:<?phpprint "A simple initial script"; //Output a line?>
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Example Script with Comments (prog2.php)
1. <html> <head>2. <title> Generating HTML From PHP</title> </head>3. <body> <h1> Generating HTML From PHP</h1>4. <?php5. //6. // Example script to output HTML tags7. //8. print "Using PHP has <i>some advantages:</i>";9. print "<ul><li>Speed</li><li>Ease of Use </li><li>Functionality
</li></ul>"; //Output bullet list10. print "</body></html>";11. ?>
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Alternative Comment Syntax
• PHP allows a couple of additional ways to create comments.<?phpphpinfo(); # This is a built-in function?>
• Multiple line comments. <?php/*A script that gets information about thePHP version being used.*/phpinfo(); ?>
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Summary
• You can embed a PHP script within an HTML document or run it as a stand-alone script.
• To begin working with PHP you need a Web server with built-in PHP, a client machine with a basic text editor
• PHP script process: write the PHP script, copy its file to the Web server, and access the file with a Web browser.
• Comments can be preceded by two forward slashes (//).
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Contents to be covered (Wk 1-8)• Variables, Operations and Expressions• Control statements
– if statements– for & while loops
• Arrays – 1-dimensional – 2-dimensional (tables)
• Functions• Form handling• File handling
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Resources
• www.w3schools.com/php/• www.php.net/manual/
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