web services8 (1).pdf for computer science

Computer Science
Class XII ( As per
CBSE Board)
Chapter 8
Web services
Visit : python.mykvs.in for regular updates
New
syllabus
2023-24

Web services
Web service - is a standardized medium,protocol or language to propagate
communication between the client and server applications on the World
Wide Web. A web service is a software module that is designed to
perform a certain set of tasks.
Web services are invoked by the user directly or indirectly to provide
services to the program/software which is being used as a part of
WWW.User may be unaware about such web services.
The web services can be searched for over the network and can also be
invoked accordingly.
When invoked, the web service would be able to provide the functionality
to the client, which invokes that web service.

Web services
Many people think that the internet and the world wide web (WWW) are
the same thing. While they are closely linked, they are very different
systems.
The internet is a huge network of computers all connected together. The
world wide web (‘www’ or ‘web’ for short) is a collection of webpages
found on this network of computers. Our web browser uses the internet
to access the web.
The World Wide Web is a way of exchanging information between
computers on the Internet, tying them together into a vast collection of
interactive multimedia resources.
World Wide Web was created by Timothy Berners Lee in 1989 at CERN in
Geneva. World Wide Web came into existence as a proposal by him, to
allow researchers to work together effectively and efficiently at CERN.
Eventually it became World Wide Web.

Web services
Web architecture –
Web is a two – tiered architecture.
• A web browser display information contents
• Web server that transfers information to the client

Web services
HTML – Hyper text markup language is a document design language not a
programming language. It provide various kinds of tags(commands) used to
define the structure and appearance of web page.
HTML was created by Sir Tim Berners-Lee in late 1991 but was not released
officially, which was published in 1995 as HTML 2.0. HTML5 is the latest evolution
of the standard that defines HTML.

Web services
Basic structure of HTML document –
<html>
<head>
<title>simple document</title>
</head>
<body>
<p>a simple paragraph</p>
</body>
</html>
Save above content in text editor with .html extension and open it in web
browser to run it(tags).Generally/Most of the tags are written as part of <body>
tag.
List of HTML Tags

Web services
Extensible Markup Language (XML) is a markup language that defines a set
of rules for encoding documents in a format that is both human-readable
and machine-readable.
XML is Platform Independent and Language Independent: The main benefit
of xml is that we can use it to take data from a program like Microsoft SQL,
convert it into XML then share that XML with other programs and
platforms. You can communicate between two platforms which are
generally very difficult.

Web services
BASIS FOR
COMPARISON
XML
HTML
Expands to Extensible Markup Language Hypertext Markup Language
Basic Provides a framework for markup HTML is predefined markup language.
Structural Information Provided Does not contain structural information
Language type Case sensitive Case insensitive
Purpose of the language Transfer of information Presentation of the data
Errors Not allowed Small errors can be ignored.
Whitespace Can be preserved. Does not preserve white spaces.
Closing tags Compulsory to use closing tags. Closing tags are optional.
Nesting Must be properly done. Not much valuable.
Difference between HTML and XML

Structure of XML Document System
A XML Document is intended to display data like HTML.
An XML document system comprises the following-
 Style Sheet (CSS or XSL)
It defines the style (How it would appear i.e. font,
color, size alignment etc.) of the elements.
 Grammar Structure (DTD)
It is optional component in XML document system
and defines the Rules of the document (Tag
definitions).
 XML File
It contains and describes actual data.
Web services

How to Prepare XML Document
In order to prepare XML Document system, you may
do the following steps-
 Prepare XML document file as per problem
XML document is divided into two part.
1. The Prolog :
Preface or Introduction to the XML document. It
includes An XML declaration, Comments etc.
2. The Data Instance :
It contains actual data.
 Prepare a style-sheet file for XML file
It contains style rules that tells a browser how to
display an XML document.
 Link the XML file with Style sheet
Web services

Example to create XML document
 Expected View on Browser
Computer Parts
Mother Board
Asus
P3B-F
1230.00
TFT Monitor
LG Electronics
995e
8500.00
Suppose we
want to make an
XML document
which is
displayed in
browser as
shown here
Web services

 Preparation of XML (test.xml) document
<?xml version=“1.0” encoding = UTF-8“ ?>
<?xml-stylesheet type=“text/css” href=“parts.css”?>
<PARTS>
<TITLE> Computer Parts </TITLE>
<PART>
<PARTNAME>Mother Board</PARTNAME>
<MANUFACTURER>Asus</MANUFACTURER>
<MODEL>P3B-F</MODEL>
<COST>1230.00</COST>
</PART>
<PART>
<PARTNAME>TFT Monitor</PARTNAME>
<MANUFACTURER>LG Electronics</MANUFACTURER>
<MODEL>995e</MODEL>
<COST>8500.00</COST>
</PART>
</PARTS>
Prolog
Data
Instance
Linking of .css
(Style Sheet) file
Web services

 Preparation of StyleSheet (part.css) file
PARTS
TITLE
PART
PARTNAME
{display:block}
{display:block; font-fanily:arial; color:#008000;
font-weight:600; font-size:16 margine-top:12pt;
text-align:center}
{display:block}
font-weight:400; font-size:14 margine-left:10pt;
margin-top: 10pt}
MANUFACTURER {display:block; font-fanily:arial; color:#600060;
margin-top: 10pt}
MODEL
COST
margin-top: 10pt}
margin-left: 5pt}
Web services

HTTP - HTTP stands for hypertext transfer protocol and is used to transfer data across
the Web. It allow users of the World Wide Web to exchange information found on web
pages. When accessing any web page entering http:// in front of the address tells the
browser to communicate over HTTP.
How It Works-
It is a connectionless text based protocol. Clients (web browsers) send requests through
request object of http to web servers for web pages / images etc.Web server respond
accordingly through response object of http After this cycle(request – response), the
connection between client and server across the Internet is disconnected. A new connection
must be made for each request(means for each web page).
This diagram shows the
working of http protocol.
Working with dns server
and working with web
Server both.
Web services

DNS –The Domain Name System, translates human readable domain
names (for example, www.python.mykvs.in) to machine readable IP
addresses (for example, 182.156.84.26). ... DNS servers translate requests
for names into IP addresses.
A domain name is our website name. e.g. in python.mykvs.in , in is primary
domain,mykvs is subdomain of in and python is subdomain of mykvs.
Generic domain name - .com,.edu,.gov,.mil,.net,.org etc
Country specific domain name - .in for india,.us for united states
Request python.mykvs.in
Response 182.156.84.26
Local DNS server
Make http Request to 182.156.84.26
Http response
Web services

URL –Uniform Resource Locator is defined as the global address of
documents and other resources on the World Wide Web. The URL is
an address that sends users to a specific resource online, such as a
webpage, video or other document or resource.
e.g.
http://python.mykvs.in/syllabus/cs12.pdf
protocol subdomain domain name path
Web services

Web services
Web page - A html document which can be displayed in a web
browser.
Website - A collection of web pages which are grouped together
and usually connected together in various ways. Often called a
"web site" or simply a "site.“
Web browser – A software which interpret html document and
display them in human readable form is known as web browser.
E.g. Firefox, Google Chrome, Opera, Microsoft Internet Explorer or
Edge, or Apple's Safari. These are also often called just "pages.“
Web server – A software which host website and return web pages
to web client(web browser) on request. E.g. Apache Tomcat,
Microsoft’s Internet Information Services (IIS) Windows Server ,
Nginx web server , Jigsaw , Zeus web server

Web services
Domain Name-Domain name is the address of your website that
people type in the browser’s URL bar to visit your website.
Web hosting - Web hosting is the place where all the files of your
website live. It is like the home of our website where it actually
lives.
A good way to think about this is if the domain name is the address
of our house, then web hosting is the actual house that address
points to. All websites on the internet, need web hosting.
Domain names and web hosting are two different services.
However, they work together to make websites possible.It is
possible with the system known as DNS.

Web services
There are four main types of web hosting:
• Shared hosting – share by multiple domains/web sites.
• VPS (virtual private server) hosting - The main server is split into
multiple virtual servers—hence the name. These virtual servers
can be customized by individual websites.
• Dedicated hosting - Websites being hosted on a dedicated server
have complete technical control over the server settings. We
choose the software, configurations, and anything else we need.
• Cloud hosting - Cloud hosting plans come with multiple remote
servers. Each server has different responsibilities. If one of the
servers is compromised or has a problem, the other servers on the
network will take over those responsibilities and pick up the slack.
• Reseller hosting and WordPress hosting are also specific types of
hosting

web services8 (1).pdf for computer science

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