http messages

Question 1

What is a client?

Answer 1

service requesters; initiate communication sessions with servers, which await incoming requests

i.e., typical web user’s internet-connected devices

Question 2

What is a server?

Answer 2

providers of a resource or service; share their resources with clients; abstraction

Question 3

Which HTTP method does a browser issue to a web server when you visit a URL?

Answer 3

HTTP GET request: requests a representation of the specified resource; requests using GET should only be used to request data (they shouldn’t include data)

Question 4

What three things are on the start-line of an HTTP request message?

Answer 4

1. http method: describes action to be performed
2. request target: the URL or path to get data from
3. http version: defines the structure of message and of the requested response

Question 5

What three things are on the start-line of an HTTP response message?

Answer 5

1. protocol version: usually HTTP/1.1
2. status code: indicating success/failure of request
3. status text: description of the status code

above all, something like this:
HTTP/1.1 404 Not Found

Question 6

What are HTTP headers?

Answer 6

let the client and the server pass additional information with an HTTP request or response like html headers

a case-insensitive string followed by a colon (‘:’) and a value whose structure depends upon the header

Question 7

Where would you go if you wanted to learn more about a specific HTTP Header?

Answer 7

mdn or Internet Assigned Numbers Authority

Question 8

Is a body required for a valid HTTP request or response message?

Answer 8

no

requests fetching resources, like GET, HEAD, DELETE, or OPTIONS, usually don’t need one. Some requests send data to the server in order to update it: as often the case with POST requests (containing HTML form data)

Question 9

client-server examples

Answer 9

email, network printing, and the www

Question 10

http messages types

Answer 10

1. requests sent by the client to trigger an action on the server
2. responses, the answer from the server
   ultimately: HTTP messages are the key in using HTTP

Question 11

http requests and responses are composed of?

Answer 11

1. start-line: the requests and the success/failure of the request (always a single line)
2. optional: http headers: specifying requests or describing the body of included in the message
3. blank line for all the meta-info that has been requested was sent
4. optional: body: data associated with the request or document associated with a response

Question 12

http acronym meaning

Answer 12

HyperText Transfer Protocol: allows the fetching of resources; defines a language for clients and servers to speak to each other.

Question 13

http messages recap

Answer 13

….

Question 14

What is a client?

Answer 14

service requesters

Question 15

What is a server?

Answer 15

providers of a resource or service

Question 16

Which HTTP method does a browser issue to a web server when you visit a URL?

Answer 16

HTTP GET

Question 17

What is on the first line of an HTTP request message?

Answer 17

1. http method: describes action to be performed
2. request target: the URL or path to get data from
3. http version: defines the structure of message and of the requested response

Question 18

What is on the first line of an HTTP response message?

Answer 18

1. protocol version: usually HTTP/1.1
2. status code: indicating success/failure of request
3. status text: description of the status code

above all, something like this:
HTTP/1.1 404 Not Found

Question 19

What are HTTP headers?

Answer 19

let the client and the server pass additional information with an HTTP request or response like html headers

a case-insensitive string followed by a colon (‘:’) and a value whose structure depends upon the header

Question 20

Is a body required for a valid HTTP message?

Answer 20

no

requests fetching resources, like GET, HEAD, DELETE, or OPTIONS, usually don’t need one. Some requests send data to the server in order to update it: as often the case with POST requests (containing HTML form data)