server-side development

Question 1

what does node.js do

Answer 1

runs js on the server side

Question 2

what are http methods

Answer 2

textual commands passed via http protocols between the client and the browser

Question 3

GET

Answer 3

requesting/retrieving content

Question 4

POST

Answer 4

sending data and retrieving content

Question 5

what is a web server

Answer 5

software that runs on the server or cloud infrastructure

Question 6

what does the web server do

Answer 6

handles http requests
listens for tcp connection requests from clients

Question 7

what is a port

Answer 7

communication endpoints for a host on a network using tcp

Question 8

how many processes can be assigned to a port at once

Answer 8

1

Question 9

how many well known ports are there

Answer 9

1023

Question 10

what is the software loopback ip

Answer 10

127.0.0.1

Question 11

what are endpoints in node

Answer 11

code intended to receive a request from a client

Question 12

how can endpoints in node be distinguished

Answer 12

via the url and the http method

Question 13

node routes

Answer 13

the connection of the http request to the endpoint

Question 14

response object

Answer 14

what you send back to the client

Question 15

request object

Answer 15

what came in from the client/browser
an object is created to encapsulate this information

Question 16

what is AJAX and what does it do

Answer 16

asynchronous javascript and xml
allows content to be updated after loading a page without intervention from the user which allows for dynamic pages

Question 17

how does AJAX work

Answer 17

after the page has loaded we use js at the client side to query the server
the server responds with content which is processed by js and if we need to the page is updated without being reloaded

Question 18

why dont we need html in ajax

Answer 18

we dont need to render the page

Question 19

what is axois

Answer 19

a http client library that runs in browser and on node.js that simplifies querying a web service in js

Question 20

how do we handle errors in axios

Answer 20

promises; then and catch

Question 21

what does express do

Answer 21

simplifies handling http requests in js/node.js

Question 22

+ url encoded parameters

Answer 22

the simplest way of passing data

Question 23

how do we pass multiple parameters in url encoded parameters

Answer 23

separating them with &

Question 24

res.end (express)

Answer 24

ends the response ; nothing else should follow it

Question 25

res.send (express)

Answer 25

can be used multiple times to construct a response

Question 26

CORS

Answer 26

cross origin response sharing: a security feature that allows or restricts resources on a web page to be requested from another domain outside the domain where they originated from

Question 27

what is the difference between GET and http POST

Answer 27

get encodes the data in a url whilst with post the data is encoded in a http request

Question 28

what is http post used for

Answer 28

sending content of a html form to the server

Question 29

what does the json parser look like and what is its role

Answer 29

app.use(express.json()); parses the incoming requests

Question 30

how do we access incoming data with json

Answer 30

const name = req.body.q

Question 31

when should POST be used and why

Answer 31

when wanting to send data not 'visible' so more secure no restriction on data length

Question 32

when should we use GET and what are the downsides of using it

Answer 32

when retrieving web pages no security kept in browser history

Question 33

what is the format of json when sending data using POST

Answer 33

key value pairs e.g. {"str": "words"}

Question 34

what is the role of web sockets

Answer 34

allow you to keep the connection open between the client and server in js so the server can send back data to the client as necessary

Question 35

how do we set up web sockets on the server

Answer 35

we use a server object to create it a http connection is 'upgraded' to a web socket as requested we handle the socket like a get (wss.on) and send responses to the client then disconnect when done (ws.close())

Question 36

what module is used by node to interact with files

Answer 36

fs

Question 37

how do we read and send files with node

Answer 37

readFile(filename, callback) sendFile(filename, callback)

Question 38

what does _dirname mean when using files

Answer 38

the path where the currently running script is

Question 39

. (fs module)

Answer 39

current directory

Question 40

..(fs module)

Answer 40

up a directory

Question 41

/(fs module)

Answer 41

filesystem root

Question 42

what is the point of a db

Answer 42

allows you to store and access data efficiently

Question 43

sql as a relational database

Answer 43

data is in tables

Question 44

sql as non-procedural

Answer 44

you specify what to do not how to do it

Question 45

when do we use sqlite

Answer 45

for smaller embedded applications

Question 46

.verbose() (sqlite)

Answer 46

gives more info on the errors