5. 6. 7. The Web

Question 1

What is the Web?

Answer 1

A DS for linking together hypertext documents.

A client server architecture with pages hosted by web servers and viewed by client web servers

Question 2

What is the protocol for communication between client and server?

Answer 2

HTTP, pages written using hyper text markup language

Question 3

Pros and cons of client server architecture?

Answer 3

Pro: behaviour easy to understand
Con: server is a single point of failure and performance bottleneck

Question 4

What makes the web reliable?

Answer 4

Statelessness. Every request is independent of every other.

Question 5

What is a URI

Answer 5

Universal Resource Identifier.

A URI that specifies locations is URL (http://www.example.com). One that specifies name is URN (book code)

Question 6

What are the eight different methods of HTTP?

Answer 6

GET- request named resource
HEAD- metadata about a resource
POST- client sends data to server
PUT- put information from client to web server
DELETE- delete a resource
TRACE- used for debugging
OPTIONS- which commands a server will respond to
CONNECT- begins communication with resource

Question 7

What happens when a user decides on a page to view?

Answer 7

Client connects to the appropriate server- Look at protocol, Look at DN, find IP address
Fetches the content- GET
Renders it nicely so the user can see
Disconnects

Question 8

How can a web application appear to hold state?

Answer 8

GET and POST- client sends info about itself to the server so it can be recognised next time
Cookies- request the client to remember something and pass it back to the server next time

Question 9

Key Properties of the web?

Answer 9

Single point to point communication
Client/server architecture
Stateless communication
Common port 80
Every transaction is independent of every other as far as protocol is concerned.