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2440: 141
Web Site Administration
Web Server-Side Programming
Instructor: Joseph Nattey
The Need for Programming Languages
Web pages with just HTML statements are static pages
Pages that contain programming statements allow
changes and they are called dynamic pages
Programming languages can also be used to update
databases and communicate with other systems
Programming Languages
a programming language processes information from the
user and from data stored in a database.
the result of the processing can consist of a report sent to
the user or data returned to the database.
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Programming Languages
The data can come from a variety of sources including a
user who typed information on a web page.
Programming languages perform three basic steps
Input data, Processes data, Store data, Output data
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Programming
Programming languages process data in three ways,
sequence, decision/logic, repetition/iteration
Sequence – one instruction after another is processed
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Programming
Programming languages process data in three ways.
Decision/logic – based on data more than one option is
possible.
Pseudo code for .10 percent book
discount with purchase of more
than 3 books:
if (books > 3 then
totSales = sales * .10
else
totSales = sales
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Programming
Programming languages process data in three ways.
Repetition – also known as looping or iteration structures,
provides our program logic with ability to repeat a block of
statements based on the evaluation
of a Boolean expression.
Pseudo code to repeat a sequence
statement 10 times:
while cnt < 10
total = cnt * qty
Flow Chart to repeat a sequence
statement 10 times:
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Programs
Programs are written to perform specific tasks
Programming is accomplished using major elements such as:
Syntax and Expressions
Comments
Literal Values
Data Types and Variables
Input/Output Data
Arithmetic Operations
Logical Operations
Selections/Decisions
Repetitions/Looping
Arrays
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Web Programming Languages
Web pages that contain only HTML/XHTML statements
are called static pages
Web pages that contain programming statements are
known as dynamic pages (allow the content to change)
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Web Programming Languages…
Programming languages can be used to create:
Dynamic webpages on client Web browsers
Using client-side scripting languages such as JavaScript and
VBScript
Dynamic webpages that run on Web servers and update
databases
Using server-side scripting languages such as Java Server Pages
(JSP), Active Server Pages (ASP), ASP,NET, PHP, Coldfusion, etc
Using SQL on DBMSs such as Oracle, MySQL, SQL Server, DB2, etc
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Server-Side Programming
Server-side programs provide dynamic content and
allows interaction with Web users using:
DHTML
Active Server Pages (ASP)
Servlets and Java Server Pages (JSP)
PHP: Hypertext Preprocessor (PHP)
Practical Extraction and Reporting Language (Perl)
Databases
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Dynamic Documents
Dynamic HTML (DHTML) is a term for a combination
of client-side technologies that produce dynamic
documents
DHTML can be used to create simple animations,
images, and text with resources such as:
HTML/XHTML
Style sheets (CSS)
Client-side scripting (JavaScript or VBScript)
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Web Applications
Web applications use a combination of the following
HTML/XHTML
Style sheets (CSS)
Client-side scripting languages
such as JavaScript or VBScript
Server-side scripting languages
Such as ASP, ASP.NET, PHP, JSP, etc
Database Management Systems (DBMS) to create and
manipulate databases
Usually using the embedded Structured Query Language (SQL)
especially in Relational Databases.
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HTML Form Page
<html>
<head>
<title>HTML Form Page</title>
</head>
<body>
<form action=“http://localhost/cgi-bin/perl/hello.cgi”
method=“post”>
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<input name=“firstname” type=“text” />
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<input value=“Send” type=“submit” />
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</form>
10. </body>
11. </html>
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Web Server-Side Programming
Opening <html> tag
Opening <head> tag
Specifying the title of the page (HTML Form
Page) with the two-sided <title> tag
Closing </head> tag
Opening <body> tag
Opening <form> tag specifying the recipient
CGI file using the action attribute and the
method of sending data (using the HTTP’s
post) with the method attribute
Using the <input> tag’s type attribute to
specify the form component (text for textbox)
being used to accept data, and the name
attribute to uniquely identify the component
Using the <input> tag’s type attribute to
specify a submit button (submit) being used
to send data, and the value attribute for the
button’s caption
Closing </form> tag
Closing </body> tag
Closing </html> tag
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DHTML Sample Code
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<html>
<head>
<script type = "text/javascript">
document.writeln("Hello World");
</script>
<style type=“text/css”>
p {color: blue}
</style>
<title>DHTML Page</title>
</head>
<body>
<p> Embedded style </p>
<p style="color: red"> Inline style </p>
</body>
</html>
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Web Server-Side Programming
Opening <html> tag
Opening <head> tag
Opening <script> tag specifying the script
language of choice (JavaScript)
Displays text (“Hello World”) on a browser
Closing </script> tag
Opening <style> tag specifying the style sheet
type (css – cascading style sheet)
Specifying a value of blue as the text color for
all paragraphs on the page – Embedded style
Closing </script> tag
Specifying the title of the page (DHTML Page)
with the two-sided <title> tag
Closing </head> tag
Opening <body> tag
Displays a paragraph on the page
Displays a paragraph with an Inline style
Closing </body> tag
Closing </html> tag
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Active Server Pages (ASP)
Microsoft’s server-side technology for creating
dynamic Web pages
Based on Microsoft’s Component Object Model
(COM) and ActiveX Controls
COM is a Microsoft standard that defines how software
components from different vendors can work together
ActiveX controls are components built using the COM
specifications
VBScript and JavaScript are the most popular ASP
languages but any language (such as C++, Perl, Java)
that supports COM can also be used
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ASP Page
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<%@ language=“Javascript”>
<html>
<%= “Hello World” %>
</html>
<%@ Language=VBScript %>
<html>
<head>
<title>Example 1</title>
</head>
<body>
<%
FirstVar = "Hello world!"
%>
<%=FirstVar%>
</body>
</html>
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Specifies the ASP script language using the @
directive
Opening <html> tag
Displays text on a page using the = directive
Closing </html> tag
1. Assigns the text "Hello World" to the variable FirstVar.
2. Uses HTML to make an HTML page.
3. Uses <%FirstVar%> to print out the value of the
variable FirstVar.
4. Ends the HTML page.
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Servlets and Java Server Pages (JSP)
Sun Microsystem’s alternative to Microsoft’s ASP
Rely on Sun’s Java programming language
Java – a portable object-oriented language
Servlets – are server-side programs like CGI programs but
run as part of the Web server instead of executing as
separate processes (as CGI scripts do)
JSP – provides the same benefits of servlets
lets you mix regular, static HTML with dynamically-generated
HTML.
JavaBeans – a component model written in Java to allow
developers write reusable components
JSP’s solution to separate content from presentation
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JSP Page
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<html>
<%= “Hello World” %>
</html>
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Opening <html> tag
Displays text on a page using the =
directive
Closing </html> tag
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PERL
(gyina)
Perl is the Swiss Army chainsaw of scripting
languages: powerful and adaptable.
It was first developed by Larry Wall, a linguist working
as a systems administrator for NASA in the late 1980s,
as a way to make report processing easier.
Since then, it has moved into a large number of roles:
automating system administration, acting as glue
between different computer systems; and, of course,
being one of the most popular languages for CGI
programming on the Web.
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Perl CGI Script
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#!/cgi-bin/perl
#hello.cgi – Sample perl script
print “Content-type: text/html\n\n”;
use CGI qw(:standard);
use strict;
my ($fname);
$fname = param(‘firstname’);
print “<HTML\n”;
print “<head><title>Perl CGI
Script</title></head>\n”;
print “<body>Hello $fname</body>\n”;
print “</html>\n”;
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Location of the Perl interpreter (required in
UNIX; optional in Windows)
Comment (non-executable statement)
Sends an HTML document type (text/html) to
the browser using the HTTP header line
(Content-type) and creates a new line
Allows the script to parse data from the form
when received
Prevents Perl from using undeclared variables
Declares a scalar variable (preceded by a $
sign) named fname
Assigns a form data to a variable
Sends the opening <html> tag to the browser
Sends the two-sided <head> and <title> tags
to the browser
Sends the two-sided <body> and contents of
the page to the browser
Sends the closing </html> tag to the browser
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PHP: Hypertext Preprocessor (PHP)
A simple open-source server-side programming language
used for developing interactive Web documents
Includes object-oriented programming (OOP) capabilities
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PHP Page
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<html>
<?php echo “Hello World” ?>
</html>
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Opening <html> tag
Displays text on a browser
Closing </html> tag
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Databases
Databases are a collection of data and metadata
(data about other data) about entities using a
database management system (DBMS)
DBMS – software used to create, construct and manipulate
databases
E.g. DB2, Oracle, Microsoft SQL Server, MySQL, etc
Entities – any thing, place, event, etc that data is collected
about
Data is collected in the form of attributes to help make up records
Attributes – description of an entity
Records – collection of attributes
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Database Management Systems
(DBMSs)
The purpose of a DBMS is to store data in an organized
manner for further processing
Structured Query Language (SQL) is the language used to
define and manipulate the data
Most databases are relational and organize data into
tables
DBMS
Most DBMSs use a data definition language (DDL) and
data manipulation language (DML) to help create and
manipulate databases
The most widely used DDL/DML for databases is the
structured query language (SQL) – pronounced “sequel”
Used by virtually all DBMSs
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SQL
SQL is a language embedded in virtually all DBMSs to
perform several tasks including:
Creating the structure of database objects
Using the create command
Removing database objects
Using the drop command
Changing the structure of database objects
Using the alter command
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SQL…
(kyere)
Other SQL functionalities include:
Adding records into database tables
Using the insert command
Removing records from database tables
Using the delete command
Changing records in database tables
Using the update command
Retrieve records from database tables
Using the select command
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Web Servers and Server-Side
Programming Language
Choosing a programming language for server-side
programming depends on the type of Web server to use
and vice versa
The two most popular Web servers allows you to choose
their most friendliest programming language
IIS is most friendly with ASP, ASP.NET
Apache is most friendly with PHP, JSP, etc
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