HTTPS/Node/Express

Question 1

What is a client?

Answer 1

Service REQUESTERS are clients (users?) - something that is CONSUMING resources

Question 2

What is a server?

Answer 2

Service PROVIDERS are servers

Question 3

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

Answer 3

The GET method

Question 4

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

Answer 4

HTTP method (verb like GET, PUT, POST. . . or noun like HEAD or OPTION)
-How is the request being made?
Request Target - usually a URL or absolute path
-Where is the request going?
The HTTP version (defines structure of remaining message)

Question 5

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

Answer 5

The protocol version (usually HTTP/1.1)
The status code - indicates success or failure of request
The status text - brief, informational, textual description of the status code

Question 6

What are HTTP headers?

Answer 6

Headers are where the client and server can pass additional information with an HTTP request or response.

- General Headers - apply to the message as a whole
- Request Headers - modify the request by specifying it further, giving context, or restricting it
- Representation Headers - describe the original format of the message data

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

A body is not required

Question 9

What is a CLI?

Answer 9

Command Line Interface

- An interface that receives commands from the user via text

Question 10

What is a GUI?

Answer 10

Graphical User Interface

- An interface that receives commands from users via graphical icons and audio indicators

Question 11

Give a use case for the following command:

man

Answer 11

Manual lists information on a command

Question 12

Give a use case for the following command:

cat

Answer 12

Concatenates files

Question 13

Give a use case for the following command:

ls

Answer 13

Lists directory contents

Question 14

Give a use case for the following command:

pwd

Answer 14

Prints the name of the current/working directory

Question 15

Give a use case for the following command:

echo

Answer 15

Displays a line of text . . . “echoes” the text input

Question 16

Give a use case for the following command:

touch

Answer 16

Change files timestamps

Question 17

Give a use case for the following command:

mkdir

Answer 17

Makes directories

Question 18

Give a use case for the following command:

mv

Answer 18

Moves or renames files

Question 19

Give a use case for the following command:

rm

Answer 19

Removes files

Question 20

Give a use case for the following command:

cp

Answer 20

Copies files and/or directories

Question 21

What are the three virtues of a great programmer?

Answer 21

1) Laziness:
The quality that makes you go to great effort to reduce overall energy expenditure. It makes you write labor-saving programs that other people will find useful and document what you wrote so you don’t have to answer so many questions about it.
2) Impatience:
The anger you feel when the computer is being lazy. This makes you write programs that don’t just react to your needs, but actually anticipate them. Or at least pretend to.
3) Hubris:
The quality that makes you write (and maintain) programs that other people won’t want to say bad things about.

Question 22

What is Node.js?

Answer 22

Node.js is a program that allows JavaScript to be run outside of a browser

Question 23

What can Node.js be used for?

Answer 23

It can be used to build backend Web applications, command-line programs, and automation

Question 24

What is a REPL?

Answer 24

Read-eval-print loop
- a simple interactive computer programming environment that takes single user inputs, executes them, and returns the result to the use

Question 25

When was Node.js created?

Answer 25

2009

Question 26

What is the process object in a Node.js program?

Answer 26

It is a global object that provides information about, and control over, the current process

Question 27

How do you access the process object in a Node.js program?

Answer 27

- You can access it using the require(‘process’); function and assigning it to a variable or logging it to the console - Because it is global you can just access it with the process name

Question 28

What is the data type of process.argv in Node.js?

Answer 28

An array of strings

Question 29

What is a JavaScript module?

Answer 29

A JavaScript module is a section of a program, a small section of a larger database. It is a JavaScript file in this context.

Question 30

What values are passed into a Node.js module's local scope?

Answer 30

exports, require, module, __filename, __dirname

Question 31

Give two examples of truly global variables in a Node.js program.

Answer 31

Console and process

Question 32

What is the purpose of module.exports in a Node.js module?

Answer 32

To be able to use data in one module in another module

Question 33

How do you import functionality into a Node.js module from another Node.js module?

Answer 33

You use require to import the functionality

Question 34

What is a directory?

Answer 34

A special kind of file that lists other files

Question 35

What is a relative file path?

Answer 35

The path to go from one directory to another file

Question 36

What is an absolute file path?

Answer 36

The path to a file form the root directory

Question 37

What module does Node.js include for manipulating the file system?

Answer 37

fs module

Question 38

What method is available in the Node.js fs module for writing data to a file?

Answer 38

The writeFile method

Question 39

Are file operations using the fs module synchronous or asynchronous?

Answer 39

Yes | - Base versions are asynchronous but Sync versions are synchronous

Question 40

What is NPM?

Answer 40

NPM is a software registry where open source developers can borrow and share packages of code. There are three primary components: - The Website - The Registry - The CLI

Question 41

What is a package?

Answer 41

A package is a directory with at least one file and a package.json file

Question 42

How can you create a package.json with npm?

Answer 42

With the npm init command

Question 43

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

Answer 43

- A dependency is third-party code that is required at runtime (generally a package) - You can add a dependency with the npm install command

Question 44

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

Answer 44

- It creates a module folder with the required package | - It updates the package.json file to require the dependencies

Question 45

How do you add express to your package dependencies?

Answer 45

npm install express or just npm i express

Question 46

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

Answer 46

The listen() method

Question 47

How do you mount a middleware to an Express application?

Answer 47

By using the use method or the HTTP request method as a method of the app object

Question 48

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

Answer 48

Request object and response object

Question 49

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

Answer 49

application/json; charset=utf-8

Question 50

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

Answer 50

- It tells the server what type of request a client is making - It allows us as the programmer to determine what response to send the client

Question 51

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

Answer 51

- It parses the json body of incoming requests | - We would need to mount it to our server if we are expecting clients to send json to the server