HTTP Essential Training

Question 1

What does HTTP stand for?

Answer 1

Hypertext Transfer Protocol

Question 2

what is a protocol?

Answer 2

A system of rules that allows communication between two entities, like computers

Question 3

What is hypertext?

Answer 3

essentially web documents

Question 4

what are the core principles of HTTP?

Answer 4

1. Plain Language and Human Readable (GET, POST, PUT, DELETE, CONNECT, HEAD)
2. Stateless Protocol (no memory of previous requests, prevents users from becoming trapped in the middle of process)
3. Sessions (allows user to preserve sessions, such as where they were on a website, via cookies)
4. HTTP Headers (included in requests and responses and allow information to be carried back and forth)
5. Request response pairs (each message has a request that is sent and receives a response in return)

Question 5

What are differences between HTTP/1.1 vs HTTP/2, vs HTTPS

Answer 5

2 has increased performance speed as well as more security. Requires encrypted connection (via https)

HTTP 1 sends uncompressed headers, sends one file at a time, and is not encrypted

Question 6

What is a browser

Answer 6

application used to access and navigate between html documents

Question 7

what is a user agent

Answer 7

Application acting on behalf of the user, or a client application (typically a browser)

Question 8

What is tcp

Answer 8

Short for transmission control protocol. one of the main internet protocols used by the WWW, email, FTP, and remote administration

Question 9

What is IP

Answer 9

Internet protocol, used to transfer data between computers over a network. every device connected to the internet has an IP address

Question 10

what is a URL

Answer 10

Universal Resource Locator, an address pointing at a location on the web

Question 11

what is a DNS

Answer 11

Domain name server, DNS catalogs all domain name URLs and points them to the IP addresses of servers

Question 12

What is a Resource

Answer 12

The file or files available on a server when following a URL

Question 13

What is a Server

Answer 13

Computer on the internet running some form of data storage sharing application, most commonly a web server application

Question 14

What is a Proxy

Answer 14

This is a software or hardware service acting as a middle person between clients and servers (often used when an IP address needs to be hidden)

Question 15

what are request-response pairs

Answer 15

This is the method of communication between a client (usually a web browser) and server. Uses HTTP to send a request, then HTTP to send back a response

Question 16

what is a Header?

Answer 16

This is what a request and response will use to identify what they are and what they want. Contains meta data

Question 17

What are the HTTP Request Methods/Verbs?

Answer 17

Every request contains a method explaining what action the sender wishes to perform on the resource (GET, PUT, PATCH, etc.)

Question 18

what is a status response code

Answer 18

This is what comes across in the response to alert the client what happened with the request (100s-500s)

Question 19

what is a cache?

Answer 19

This is the method for storing data on the client (browser) or the server to speed up performance

Question 20

what does being stateless mean?

Answer 20

HTTP is stateless, meaning every request and response is unique, and no state is stored

Question 21

what is a cookie

Answer 21

This is a small piece of information passed back and forth between the client and the server allowing each to know what state the other is in

Question 22

What is a session?

Answer 22

This is how clients and servers share information (via cookies) which allows more speedy communication between the two

Question 23

What is the flow of all HTTP Transactions?

Answer 23

1. Browser opens a TCP connection to the server. this allows data to be sent back and forth, and ensures that all data is put back together in the same way it was sent
2. Browser sends an HTTP message including a method n(such as GET) as well as a URL pointing at the requested resource
3. Server sends a message back to the browser. This will contain a response status, header, and message
4. Once the response is received the TCP connection is closed

Question 24

what are the two main pieces of a URL?

Answer 24

a protocol declaration (how to access) and a URN to a specific resource

Question 25

What are the pieces of the URN?

Answer 25

1. Host (this is the domain registered at a domain name service)
2. Connection port (default to 443 for HTTPS and 80 for HTTP)
3. Resource path (file location within the server)
4. Optional URL Query (optional and might track or filter something. These start with a ?, each query has an argument and a value, can be strung together using ampersand)

Question 26

what is the most basic way to authenticate with the server?

Answer 26

The following header followed by a username and password combo:
Authorization: username password

Question 27

Cached files greatly increase speed, but what is the potential downside of a browser using cached files?

Answer 27

The browser will not receive a new version of the files until the cached files are either cleared, or they have expired. This could prevent the browser from seeing updates that were made since the cached files were stored.