The document provides an overview of web architecture and related technologies. It discusses: - The history and basics of the World Wide Web and how it works. - Key protocols like HTTP and HTTPS, including how requests and responses are structured. - Common status codes and HTTP verbs used in requests. - The layers of a web application, including presentation, logical, and data layers. - Differences between two-tier and three-tier architectures, with two-tier having just client and data tiers while three-tier separates the logical/business tier.

1. Web Architecture
Presented By: Sudip Pudasaini
Date: 22nd SEP, 2015

2. Introduction: Me
lGraduated in BEIT From Nepal College Of Information
Technology (NCIT, 2012) .
lWorked in Himalaya College Of Engineering as a Teacher.
lWorked for 9 months.
lCurrently working in Leapfrog Technology Nepal as a Sr. Quality
Assurance Engineer.
lIt's been almost 3 years.
lEngaged in a project First Help Financial (FHF) .
lI prefer Automation and Security Testing

3. Agenda
lWWW (W3)
lHTTP & HTTPS
lRequest vs Response
lStatus Code
lHTTP Verbs
lTwo Tier & Three Tier

4. World Wide Web
lIn 1989 Sir Tim Berners - Lee Invented WWW.
lSimply known as “The Web”
lIs an information space where
ldocuments and web resources
lare identified by URIs, interlinked
lby hypertext link and can be
laccessed via Internet.
lPrimary tool to interact on Internet
lWeb Page: primarily text documents
lformatted and annotated with
lHTML.
lWebsite: Multiple web pages with
lcommon domain name.

5. HTTP & HTTPS
lHTTP:
lHypertext Transfer Protocol, Application Layer Protocol
lUse to communicate between distributed system, hosts and
clients.
lCommunication usually takes place over TCP/IP, default port is 80
but other port can also be used.
lCommunication takes place as Request/Response pair.
lCurrent Version is HTTP/1.1

6. HTTP & HTTPS
lHTTPS:
lHTTPS = HTTP + SSL (Secured Socket Layer)
lEncrypt and verify the integrity of traffic between the browser and
server.
lVerifies browser is talking to the correct server.

7. Client/Server Communication

8. Communication Failure

9. Request Vs Response
lFrom Server To Client
lServer Get Request and
send Response.
lResponse Headers,
Information about Server
environment like content-
type, content-lenght, server,
etc
lResponse Body, is actual
response being rendered to
the client's browser.
lFrom Client To Server
lClient Send Request and Get
Response.
lRequest Headers,
Information about client
environment like content-
type, content-lenght, host, etc
lRequest Body, is actual
request being sent to the
server

10. Status Code
lOr Response Code,
l1xx: Informational Message
l2xx: Successful
l3xx: Redirection
l4xx: Client Error
l5xx: Server Error

11. HTTP Verbs
lHTTP Methods
lDesired action to be performed on the identified resource.
lHTTP/1.0 specification defines GET, POST & HEAD
lHTTP/1.1 Specification added 5 new option: OPTIONS, PUT,
DELETE, TRACE & CONNECT.

12. HTTP Verbs
lGET:
lPasses all request data in URL query string.
lDo not change the server state.

13. HTTP Verbs
lPOST:
lPasses all the request data in HTTP request body.
lChange the server state by posting data.

14. HTTP Verbs
lHEAD
lIdentical with GET Request but with out response body.
lThis is useful for retrieving meta-information written in response headers.
lPUT
lUse to update known resource through URI.
lIf URI does not point to existing resource, new resource can be created.
lDELETE
lThe DELETE method deletes the specified resource.

15. Web Architecture
lOverview:
lLayers Of web application
lTwo Tier Application
lThree Tier Application

16. Layers Of Web Application
Presentation Layer:
What user sees
Client-side or “View”
Logical Layer:
Middle Tier, backend or “Control”
Underlying processing engines and their rules
Data Layer:
The physical data storage layer
Model

17. Two Tier Architecture
Client Server Communication
Divided in to two parts
Client Application (Client Tier)
Database (Data Tier)
Advantages:
Easy to maintain and modification
Faster communication
Disadvantages:
Can not handle multiple request

18. Three Tier Application

19. lThank You!