Introduction to

1
Session 1
Introduction to
Web Applications and ASP.NET
2
Session Objectives

• Describe the following -

• Web application
• Web application development cycle

• Explain Active Server Pages

• Explain the features of ASP.NET

3
Client/Server and Web Applications
Permanent Connection
Client-Server Application
Client 1
Server
Permanent Connection
Client 2
HTTP Request
Client 1 (Browser)
ActiveX Data Objects (ADO)
HTTP Response
IIS
Database
Client 2 (Browser)
Web Application
4
Web-enabled Application Architecture
Internet
Proxy Server
Client 1 (Browser)
Web server HTTP
Certificate Server
Database Server
Other servers FTP SMTP Exchange Server
Server-based programs ASP CGI ISAPI
5
HTTP at work
Page Request
Client (Browser)
SERVER
Send me Introduction to Hypertext
Client (Browser)
SERVER
Introduction to Hypertext
6
Network Interface and HTTP Service
Internet
Network Interface
Transport Layer and Internet Layer (TCP / IP)
Windows Sockets
HTTP
FTP
7
Accessing Database Information
Internet
Client (Browser)
Web server HTTP
Database Server
ODBC
8
Web Application Development Cycle

• Planning the Web application

• Designing the application

• Constructing and testing the components of the
  application

• Going live

• Production and Maintenance

9
Web Application Development Process
Idea
A
Planning Phase
Functional Specifications complete?
Construction and Testing
No
Yes
Complete?
Design Phase
No
Yes
Design complete?
Going Live
No
Production and Maintenance
Yes
A
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Scripting
?Web client Browser
Data entry
?Web Server CGI Scripts
Processing
Server-based processing
?Web client Browser JavaScript VBScript
Data entry
?Web Server CGI Scripts
Processing
Processing
Client-side processing
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Validating Data
HTML Form
User input
JavaScript data validation
Data valid?
No
Yes
Submit data to server
Valid Data
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Client-Side Scripting
Validate data
Provide user interaction
Dynamically change content
Integration
Specifies the scripting language
ltscript language"JavaScript"gt lt!-- JavaScript
statements //--gt lt/scriptgt
comment tags
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Active Server Pages

• ltHTMLgtltBODYgt
• ltCENTERgtltIgtltFONT COLOR"HOTPINK" size 5gt
• ltIf Time gt 120000 AM And Time lt 120000
  PM Thengt
• "Now the time is between 1200 am and 1200 pm"
• ltElsegt" Now the time is between 1200 pm and
  1200 am"
• ltEnd Ifgt
• lt/FONTgtlt/Igtlt/CENTERgt
• lt/BODYgtlt/HTMLgt

Executed on server
Output
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Processing of ASP file
HTTP Request
Client (Browser)
IIS
HTTP Response
ASP.DLL
ActiveX Data Objects (ADO)
VBScript
IIS
JavaScript
Database
ASP file
15
Advantages of ASP
Automatic compilation
Web page with dynamic content
ASCII text to a client browser
Pros
Inaccessible source code
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ASP file in a Web-based application
HTTP Request
Client (Browser)
IIS
HTTP Response
Active Server Components

• Active Server Pages (ASP)
• JavaScript
• VBScript

• Active Server Pages (ASP)
• JavaScript
• VBScript

• Active Server Pages (ASP)
• JavaScript
• VBScript

Database
17
Evolution of ASP.NET
Denali
First beta version of ASP
ASP 1.0
Available as an add-on to IIS 3.0
ASP 2.0
Came as a part of windows NT 4.0
ASP 3.0
Came along with Windows 2000
ASP.NET
Comes along with the .NET framework
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Drawbacks of ASP
Only two non-typed languages VBScript and
JavaScript
Interpreted ASP pages
Spaghetti-like mixture of code, HTML and text
Using the same file.
DRAWBACKS
Extra code for functionality
No Re-usage of code
No debugging mechanism
Shut down of web server to install a new version
of a DLL
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Advantages of ASP.NET
ASP.NET

• Supports strongly typed languages like C, VB

• Compiled pages improving execution speed

• An inbuilt method Trace, helps in debugging a
  page

• Supports re-use of code by the mechanism of
  inheritance

• Provides server controls that are declarative

• ASP code is separated from the HTML design and
  text

• No need to register component.

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Features of ASP.NET - 1

• Recognizes the type of client browser and
  accordingly display the contents to the client.

• Adds functionality using C or VB.NET

ASP.NET

• Uses server - side caching

• Ships with many built-in server controls

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Features of ASP.NET - 2

• Refers hierarchical namespaces.

• Global.asax file holds additional events

ASP.NET

• Web service - a function deployed and used over
  the web