HTTP, NPM, NODE, Express

Question 1

What is a client?

Answer 1

A service requestor.

Question 2

What is a server?

Answer 2

A service provider.

Question 3

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

Answer 3

a get request

Question 4

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

Answer 4

The method, verbs i.e. GET PUT, POST or a noun HEAD, OPTIONS, the target (URL), HTTP version

Question 5

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

Answer 5

Version ie. (HTTP/1.1),
status code (404),
status text i.e. 404 Not found (for human reading)

Question 6

What are HTTP headers?

Answer 6

A string followed by colons and a value.
A key value pair.

Question 7

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

Answer 7

MDN

Question 8

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

Answer 8

No. Their could just be a confirmation in the start line.

Question 9

What is AJAX?

Answer 9

Asynchronus processing request, to load data with having a user reload a page.

Question 10

What does the AJAX acronym stand for?

Answer 10

Asynchronous JavaScript And XML

Question 11

Which object is built into the browser for making HTTP requests in JavaScript?

Answer 11

XMLHttpRequest object.

Question 12

What event is fired by XMLHttpRequest objects when they are finished loading the data from the server?

Answer 12

load event.

Question 13

Bonus Question: An XMLHttpRequest object has an addEventListener() method just like DOM elements. How is it possible that they both share this functionality?

Answer 13

Prototype inheritance from the window.

Question 14

What is NPM?

Answer 14

Node-package manager.

Question 15

What is a package?

Answer 15

A directory with one or more files, of a chunk of reusable code.

Question 16

How can you create a package.json with npm?

Question 17

What is a dependency and how do you add one to a package?

Answer 17

A package that your package requires you to use. Version control, majorversion(breaking changes).minorversion(adds functionality backwards compat).bugfixversion(fixes something, should always update this)

Question 18

What happens when you add a dependency to a package with npm?

Answer 18

It gets put into your package.json, and downloads the package and all dependencies in your node-modules.

Question 19

What are some other popular package managers?

Answer 19

Yarn and PNPM.

Question 20

DEV dependencies.

Answer 20

Packages for when your in development, so they can easily removed at launch.

Question 21

Scripts in npm?

Answer 21

Scripts allow you to create shortcut keywords to run different packages.

Question 22

What is Express useful for?

Answer 22

Handling server requests.

Question 23

How does Express fit into a full-stack web application?

Answer 23

It helps handle your server requests, to get data from databases and send it to the client.

Question 24

How do you add express to your package dependencies?

Answer 24

npm i express

Question 25

What Express application method starts the server and binds it to a network PORT?

Answer 25

.listen , we use port 8080 / With httppie you can just do < http :8080 > It assumes GET and localhost

Question 26

What is Express middleware?

Answer 26

Function calls that respond to requests made to express.

Question 27

What is Express middleware useful for?

Answer 27

Modify your data, return an html page, send a file to be downloaded? Lots of things?

Question 28

How do you mount a middleware with an Express application?

Answer 28

You pass a directory as an argument and when the routing goes through this code is executed with the use method.

Question 29

Which objects does an Express application pass to your middleware to manage the request/response lifecycle of the server?

Answer 29

The request and response objects.

Question 30

Whats an api endpoint?

Answer 30

A specific URL.

Question 31

What is the appropriate Content-Type header for HTTP messages that contain JSON in their bodies?

Answer 31

application/json.

Question 32

What is the significance of an HTTP request’s method?

Answer 32

A generalization of what a server should do.

Question 33

What does the express.json() middleware do and when would you need it?

Answer 33

Parses incoming JSON.

Question 34

What is SQL and how is it different from languages like JavaScript?

Answer 34

It’ s declarative, it does what you ask.

Question 35

How do you retrieve specific columns from a database table?

Answer 35

select followed by the column and then a from what table

Question 36

How do you filter rows based on some specific criteria?

Answer 36

use the where keyword followed by column and your comparator statement.

Question 37

What are the benefits of formatting your SQL?

Answer 37

READABILITY!

Question 38

What are four comparison operators that can be used in a where clause?

Answer 38

=, !=, <, >

Question 39

How do you limit the number of rows returned in a result set?

Answer 39

the limit keyword followed by a number, must be last statement.

Question 40

How do you retrieve all columns from a database table?

Answer 40

select *
from “tablename”

Question 41

How do you control the sort order of a result set?

Answer 41

order by keyword ,defaults ascending, specify <desc> after the column name.</desc>

Question 42

How do you add a row to a SQL table?

Answer 42

insert into “tablename” (“columnname”, “columnname”)

Question 43

What is a tuple?

Answer 43

A list of values inside parentheses.

Question 44

How do you add multiple rows to a SQL table at once?

Answer 44

add commas between tuples.

Question 45

How do you get back the row being inserted into a table without a separate select statement?

Answer 45

returning * will return all sent. Is good to see autogenerated IDs

Question 46

How do you update rows in a database table?

Answer 46

update <tablename>, set <valuename> = <value>, usually followed by a filter statement
where <attribute> = <value></value></attribute></value></valuename></tablename>

Question 47

Why is it important to include a where clause in your update statements?

Answer 47

The where clause specifies which rows you should update.

Question 48

How do you delete rows from a database table?

Answer 48

DELETE
FROM <tableName>
WHERE <attributeName> = <value>
returning *;</value></attributeName></tableName>

Question 49

How do you accidentally delete all rows from a table?

Answer 49

Forgetting a where statement.

Question 50

What is a foreign key?

Answer 50

A reference to the primary key of another table.

Question 51

How do you join two SQL tables?

Answer 51

JOIN <tableName> using (<columnName>)</columnName></tableName>

Question 52

How do you temporarily rename columns or tables in a SQL statement?

Question 53

What is the purpose of the Express Static middleware?

Answer 53

to serve basic files to the client.

Question 54

What does express.static() return?

Answer 54

Returns a response object or calls next.

Question 55

What are several examples of static files?

Answer 55

CSS, Images, Index.html(when using react), basic javascript. Any files that don’t change and aren’t dynamic like react?

Question 56

What is a good way to serve application images using Express?

Answer 56

Using relative links to a static image folder. Serving them statically.