CMPT 221 - Final Review

CMPT 221 Marist Collge

Where does node.js run?

Server side

What engine does node.js use to run javascript on the server with?

Google V8 (javascript engine)

Node.js allows you to run javascript on?

the server 

Communication of server and client done mostly with?

RESTful web services

talking to database, access of API can be done through

the server (node.js)

Advantage of using node?

 It’s modular (code chunks independent and self-contained)

How can you install things like modules in Node.js?

NPM

NPM command to install express?

npm install express

How do you tell JS you’re gonna use a specific module?

require (“module name”)

What does package.json do?

It tells node what modules are being used

What are SOAP web services?

First attempt to use web services

What does SOAP stand for?

Simple Object Access Protocol

*What is a web service?*

 *A way to allow web functionality*

What is the WSDL file?

Description of web services available and how to call them

What does WSDL stand for?

Web Services Description Language

What is the WSDL file written in?

XML

What does XML stand for?

Extensible Markup Language

What replaced earlier web services and is widely used today?

RESTful web services

What does REST in RESTful stand for?

Representational State Transfer

What do RESTful web services use to transfer information?

HTML commands

RESTful web services are?

Client-server and stateless

What does stateless mean (RESTful web services)?

There is nothing saved in information transaction, so no information stored

Benefits of RESTful statelessness?

Fast performance, reliability, scalability

RESTful data is?

Cacheable

Types of data you can receive from RESTful services?

XML, HTML, JSON, Plain text

API stands for?

Application programming interface

What is RESTful API?

a protocol to call things on the server

What three things do you need for a RESTful API call?

Base URI, mime or media type, HTTP method to be used

What types of HTML methods can be used for RESTful API calls?

GET, PUT, POST, PATCH, DELETE

What does GET do?

Retrieve data

What does PUT do?

Update by override

What does POST do?

Save new instance

What does PATCH do?

Partial update

What does DELETE do?

Remove

*Info exchange between client and server called?*

*Transport*

What languages can be used for transport?

XML or JSON

What does an XML document contain?

Tags

What is the format of a tag?

What makes XML more powerful than JSON?

Allows you to create rules for the tags

In the tags Poughkeepsie, what is the attribute?

Zip = ‘12601’

In the tags Poughkeepsie, what is the element?

city

You can give as many attributes as you want to your element?

True

All tags in XML must have?

A closing tab

What does JSON stand for?

JavaScript Object Notation

JSON is what format?

Open standard format

What does a JSON file contain?

Name/value pairs

Advantages of JSON?

Easy to represent data structures, compact, very light weight, easy to translate back into javascript objects, quick to read or write, can use arrays

Is JSON or XML faster?

JSON is faster

What are the restrictions of JSON?

Properties must be in double quotes, can only represent simple expressions and not functions, no comments

To convert JS to JSON use what?

JSON.stringify()

To convert JSON to JS use what?

JSON.parse()

What architectures types do we use?

MVC, n-tier, client server

*What is n-tier architecture?*

*Divided into tiers*

What makes something a web application?

It runs on the web and can be accessed remotely

What do protocol web applications use?

HTTP protocol

What are the 3-tiers of web applications?

Presentation layer (browser), application server (eg. node, tomcat), storage

*What is a proxy?*

server application between client with a request and server with a resource

What is a proxy used for in web applications?

Used to access the internet and return information from the internet

What does a forward proxy do?

Isolates users from the internet

What does a reverse proxy do?

Isolates web server from the internet

What does a load balancer do?

Distributes the load among all the servers available

A load balancer can be hardware or software based

True

What does a load balancer use to balance the load?

Algorithms

What does the firewall do?

Restricts access to the web servers

How does the firewall work?

It closes all the ports that are not required

What do web servers do?

Serve static HTML content

What do application servers do?

Serve dynamic content

What is sometimes in front of application servers?

Web servers

What are some examples of application servers?

 Node.js, Tomcat, .net server, PHP, Netty, Jetty

What does an application server consist of?

Web server connectors (eg. AJP, HTTP, etc.), programming language environment, runtime libraries, database connectors

What are database servers used for?

To store data in an organized manner

What are the ways you can scale?

Vertically or horizontally

What does it mean to scale vertically?

Increase capacity of existing servers (CPU, memory)

What does it mean to scale horizontally?

Add more servers

Is it easier to scale horizontally or vertically?

Vertically

*What is a N-Tier architectural pattern?*

*A tiered architecture with as many tiers as necessary*

What does MVC stand for?

Model, View, Controller

What does the Model in MVC do?

Provides a way to query and change the state of the application

What is the View in MVC?

The user interface, it could query the model

What is the Controller in MVC?

Accepts input and converts into commands, translates actions into operation of the model.

Microservices work well when scaling?

Horizontally

What are microservices?

architecture where software are small independent services that communicate thru api

What does AJAX stand for?

Asynchronous JavaScript and XML

What does AJAX allow?

Asynchronous calls

What is an asynchronous call?

A call in which results can be retrieved while other transactions occur

What does AJAX use to make asynchronous calls?

Event handlers

Where does AJAX work?

Client side

What is the advantage of an asynchronous call over a synchronous call?

can do multiple transactions at once

What is XMLHttpRequest?

Interface through which the browser can make HTTP requests

Where was XMLHttpRequest started?

Internet explorer

What does XMLHttpRequest do?

Sends the request and parses the result

What is the difference between GET and POST?

In get, information is part of the url. In post, it is part of the body

*How do we change the information on the page?*

*DOM manipulation*

What is a promise?

A wrapper around an asynchronous call to the server

What is received from a promise after a call to the server?

A success or failure message

How can we store data in web apps?

Cookies and sessions

What are cookies?

Data stored on the client that is sent to the server, or vice versa, every time a call is made

Cookies can be made on the client or server side

True

What language do databases use?

SQL

What does SQL stand for?

Structured query language