server side scripting basics by Bantamlak Dejene

Chapter One:
Server Side
Scripting Basics
11/28/2019
BantamlakDejene,Information
Technology
1

Introduction to Server-Side Scripting
Today’s Web users expect exciting pages that are updated
frequently and provide a customized experience. For them, Web
sites are more like communities, to which they’ll return time
and again. At the same time, Web-site administrators want sites
that are easier to update and maintain, understanding that’s the
only reasonable way to keep up with visitors’ expectations. For
these reasons and more, PHP and MySQL have become the de
facto standards for creating dynamic, database driven Web sites.
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Technology
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Cont.….
Dynamic Web sites are flexible and potent creatures, more accurately
described as applications than merely sites. Dynamic Web sites
Respond to different parameters (for example, the time of day or the
version of the visitor’s Web browser)
Have a “memory,” allowing for user registration and login, e-commerce,
and similar processes
Almost always integrate HTML forms, allowing visitors to perform
searches, provide feedback, and so forth
Often have interfaces where administrators can manage the site’s content
Are easier to maintain, upgrade, and build upon than statically made sites.
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Cont.….
There are many technologies available for creating dynamic
Web sites. The most common are ASP.NET (Active Server
Pages, a Microsoft construct), JSP (Java Server Pages),
ColdFusion, Ruby on Rails (a Web development framework
for the Ruby programming language), and PHP. Dynamic
Web sites don’t always rely on a database, but more and
more of them do, particularly as excellent database
applications like MySQL are available at little to no cost.
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Server-Side Scripting Languages
PHP originally stood for “Personal Home Page” as it was created in 1994 by Rasmus
Lerdorf to track the visitors to his online résumé. As its usefulness and capabilities
grew, it came to mean “PHP: Hypertext Preprocessor. According to the official PHP
Web site, found at www.php.net A, PHP is a “widely used general-purpose scripting
language that is especially suited for Web development and can be embedded into
HTML.” It’s a long but descriptive definition.
Server side refers to the fact that everything PHP does occurs on the server. A Web
server application, like Apache or Microsoft’s IIS, is required and all PHP scripts
must be accessed through a URL. Its cross-platform nature means that PHP runs on
most operating systems, including Windows, UNIX, and Macintosh. More important,
the PHP scripts written on one server will normally work on another with little or no
modification.
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Technology
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Cont.….
MySQL (www.mysql.com) is the world’s most popular open-source database. In
fact, today MySQL is a viable competitor to the pricey goliaths such as Oracle and
Microsoft’s SQL Server. Like PHP, MySQL offers excellent performance,
portability, and reliability, with a moderate learning curve and little to no cost.
MySQL is an RDBMS. A database, in the simplest terms, is a collection of data, be
it text, numbers, or binary files, stored and kept organized by the DBMS.
MySQL is an open-source application, like PHP, meaning that it is free to use or
even modify. There are occasions in which you should pay for a MySQL license,
especially if you are making money from the sales or incorporation of the MySQL
product. The MySQL software consists of several pieces, including the MySQL
server, the MySQL client, and numerous utilities for maintenance and other
purposes. PHP always had good support for MySQL, and that is even truer in the
most recent versions of the language.
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Use Basic Syntax
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Page Title</title></head>
<body>
</body></html>
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Cont.….
<title>Basic PHP Page</title></head>
<body><!—Example 2 - first.php -->
This is standard HTML.<?php?></body></html>
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Send Data to Web Browser
<! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
<head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"
/>
<title>Using Echo</title></head>
<body>
This is standard HTML.
<?php
echo This is generated by using PHP!
?></body></html>
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Write Comments
<title>Comments</title></head>
<body><?php
# Example 4 - comments.php
# Created March 16, 2011
# Created by Larry E. Ullman
# This script does nothing much.
echo 'This is a line of text. 
This is another line of text.';
/*
echo 'This line will not be executed.';
*/
echo "Now I'm done.";
// End of PHP code.
?></body></html>
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Utilize Variables
Regardless of what type you are creating, all variable names in
PHP follow certain syntactical rules:
A variable’s name must start with a dollar sign ($), for example, $name.
The variable’s name can contain a combination of letters, numbers, and
the underscore, for example, $my_report1.
The first character after the dollar sign must be either a letter or an
underscore (it cannot be a number).
Variable names in PHP are case sensitive! This is a very important rule. It
means that $name and $Name are entirely different variables.
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Cont.….
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN“
<title>Predefined Variables</title></head>
<body><?php # Example 5 - predefined.php
// Create a shorthand version of the variable names:
$file = $_SERVER['SCRIPT_FILENAME'];
$user = $_SERVER['HTTP_USER_AGENT'];
$server = $_SERVER['SERVER_SOFTWARE'];
// Print the name of this script:
echo "You are running the file: $file.n";
// Print the user's information:
echo "You are viewing this page using: $usern";
// Print the server's information:
echo "This server is running: $server.n";
?></body></html>
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Manipulate Strings
A string is merely a quoted chunk of characters: letters, numbers, spaces, punctuation, and so
forth. These are all strings:
-> ‘Tobias’ -> “In watermelon sugar” -> ‘100’ -> ‘August 2, 2011
Make a string variable, assign a string value to a valid variable name:
$first_name = 'Tobias'; $today = 'August 2, 2011';
When creating strings, you can use either single or double quotation marks to encapsulate the characters,
just as you would when printing text. Likewise, you must use the same type of quotation mark for the
beginning and the end of the string. If that same mark appears within the string, it must be escaped: $var =
"Define "platitude", please."; Or you can also use the other quotation mark type: $var = 'Define
"platitude", please.';
To print out the value of a string, use either
echo or print:
echo $first_name
To print the value of string within a context, you must use double quotation marks:
echo "Hello, $first_name";
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Cont.….
<head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Strings</title></head>
<body><?php # Example6 - strings.php
// Create the variables:
$first_name = 'ሐዲስ';
$last_name = 'አለማሁ';
$book = 'ፍቅር እስከ መቃብር';
// Print the values:
echo "The book $book was written by $first_name $last_name.";
?></body></html>
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Cont.….
<body><?php # string concatenation, length and word counting =>
string_concat.php
$favoriteAnimal = 'cat';
$myArray ['age']= '28';
$about = "My age";
$len = strlen($about);
$word = str_word_count("My favorite animals are {$favoriteAnimal}s");
echo "My favorite animals are {$favoriteAnimal}s => There are {$word} words in
this sentence"; // using curly bracket
echo $about . " is " . $myArray["age"] . ""; // using . operator
echo "The length of " . $about . " is " . $len;
?></body></html>
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Cont.….
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-
transitional.dtd">
<body><?php # string search and count => string_search.php
$su = 'Welcome to Samara University. Welcome to Department of Information Technology 
This is the Department of Information Technology from College of Engineering and Technology in Samara University';
$search = strstr($su, "Engineering");// searches the string from the sentence
$searchF = strpos($su, "University");// locates the string starting from beginning
$searchE = strrpos($su, "Samara");// locates the string starting from end
$count = substr_count($su, "Technology");//counts the repetition of the string in the text
$countS = substr_count($su, "to", 9);//counts the repetition of the string in the text starting form the given index
$countF = substr_count($su, "of", 45, 100);//counts the repetition of the string in the text between the indexes
echo $su . "";
echo "Engineering is found at => ". $search . "";
echo "University is found at => " . $searchF . " => from the beginning ";
echo "Samara is found at => " . $searchE . " => from the end ";
echo "Technology is repeated => " . $count . " => times in the text ";
echo "to is repeated => " . $countS . " => times in the text starting from index 9 ";
echo "of is repeated => " . $countF . " => times in the text between index 45 and 100 ";
?></body></html>
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Cont.….
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<body><?php # string manipulation => string_manipulation.php
$myString = "It was the best of times, it was the worst of times";
$string = "Here's a little string";
$str = "Information Technology";
echo $myString . "";
echo str_replace("times", "bananas", $myString, $num ). "";//replaces all and count it
echo "The text was replaced $num times. ";
echo substr_replace($myString, "bananas", 11 ). "";//replaces from the given index
echo substr_replace($myString, "bananas", 19, 5). "";//replaces from the given index to the given number of characters
echo substr_replace($myString, "really", 3, 0) . "";
echo strtr($myString, " '", "+-"). "";
echo strtolower($str) . "";
echo ucfirst($str) . "";
echo lcfirst($str) . "";
?></body></html>
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Cont.….
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<head><title>Type Specifiers in Action</title >
<link rel="stylesheet" type="text/css" href="common.css"></head>
<body><h1>Type Specifiers in Action</h1>
<?php
$myNumber = 123.45;
printf("Binary: %b ", $myNumber);
printf("Character: %c ", $myNumber);
printf("Decimal: %d ", $myNumber);
printf("Scientific: %e ", $myNumber);
printf("Float: %f ", $myNumber );
printf("Octal: %o ", $myNumber );
printf("String: %s ", $myNumber );
printf("Hex (lower case): %x ", $myNumber );
printf("Hex (upper case): %X ", $myNumber );
?></body></html>
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Manipulate Numbers Work with Constants
PHP has both integer and floating-point (decimal) number types. These two types can be
classified under the generic title numbers without losing any valuable distinction (for the most
part). Valid number-type variables in PHP can be anything like
-> 8 -> 3.14 -> 10980843985 -> -4.2398508 -> 4.4e2
Notice that these values are never quoted—quoted numbers are strings with neither numeric
values— nor do they include commas to indicate thousands. Also, a number is assumed to be
positive unless it is preceded by the minus sign (-). Along with the standard arithmetic
operators
you can use on numbers (Table 1.1), there are dozens of functions built into PHP. Two
common ones are round( ) and number_format( ). The former rounds a decimal to the
nearest integer:
$n = 3.14;
$n = round ($n); // 3
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Cont.….
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<title>Numbers</title></head><body>
<?php # Script 1.8 - numbers.php
// Set the variables:
$quantity = 30; // Buying 30 widgets.
$price = 119.95;
$taxrate = .05; // 5% sales tax.
// Calculate the total:
$total = $quantity * $price;
$total = $total + ($total * $taxrate);
// Calculate and add the tax.
// Format the total:
$total = number_format ($total, 2);
// Print the results:
echo "You are purchasing " . $quantity . " widget(s) at a cost of $" . $price .
" each. With tax, the total comes to $" . $total . ".";
?></body></html>
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Cont.….
<title>Constants</title></head><body>
<?php # Script 1.9 - constants.php
// Set today's date as a constant:
define ('TODAY', 'March 16, 2011');
// Print a message, using predefined constants and the TODAY constant:
echo 'Today is ' . TODAY . '. This server is running version ' . PHP_VERSION .
'
of PHP on the ' . PHP_OS . ' operating system.';
?></body></html>
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THANK YOU
11/28/2019
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server side scripting basics by Bantamlak Dejene

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server side scripting basics by Bantamlak Dejene