Module 1 Week 1 Flashcards
Why does backend development pay more than front end development?
Because it requires more set up, configuration, resources, and IT structural knowledge.
Full stack developers must have a solid grasp of…
Planning, architecture, design, development, deployment, and maintenance.
Examples of soft skills include…
Communication and listening to understand, not just respond.
Backend developers build the schema. What is the schema?
A representation of a plan or theory in the form of an outline or model.
True or false? Backend developers build the architecture of how data is used.
True
What are the two types of networks?
Wired and wireless
Can network switches connect to other network switches?
Yes
What is a web server?
A computer that runs applications and service ranging from websites to instant messaging.
Why do they get the name servers?
Because they provide a service to another computer and it’s user (also known as the client)
Where and how are servers stored?
In data centers with hundreds to thousands of other servers.
What is the roll of a data center?
To ensure servers have continuous power, continuous internet connection, and are kept cool 24 hours a day.
Servers are built based on what?
The purpose they serve
Servers for only storing images would most likely have what?
A lot of hard drive space
Servers for computing complex calculations would most likely have what?
A fast processor and a lot of memory
The physical components of a server are called what?
Server hardware
The code that runs on server hardware is called what?
Software
The functions of a web server are…
Website storage & administration, data storage, security, managing email. and handling web requests.
When you type a website into your browser it is the web servers job to respond with the contents of that website. What is this called?
The request-response cycle
Web servers are designed to…
Respond to thousands of requests by clients per second
A webpage is…
A document that displays images, text, videos, and other content in the web browser.
A website is…
A collection of webpages that are linked together.
How many years would it takes to download all the webpages on the internet with our current speed?
3,000,000 years
True or false? All the billions of webpages rely on the same core technologies.
True
A webpage is what in its most basic form?
A text document
What does html do?
It structures the content we see
What does css do?
Controls the colors and style
JavaScript is responsible for what?
The user interaction
What does html stand for?
Hypertext Markup Language
How does html work?
By using markup tags, and the tags describe the content displayed in the browser window.
Html is made up of…
Headings, paragraphs, images, and multimedia elements like audio and video.
The way html describes content is known as what?
Markup
What does CSS stand for?
Cascading Style Sheets
CSS is commonly known as what?
Styling
What does CSS do?
Enhances html elements by telling them how to display.
What is JavaScript?
A programming language built into web browsers.
What does JavaScript do?
Provides web developers with tools for interactivity, data processing, control, and action.
A couple examples of JavaScript in action are…
A website telling you your login information is wrong and a video website updating in real time.
How is each line of code processed?
In sequential order.
When code is processed first to last like building blocks. The process is known as…
Page rendering
True or false? The response from the web server must be a complete webpage in order to fulfill the request and show the page in the browser.
True
A web browser is…
A software application used to browse the world wide web
URL stand for what?
Uniform Resource Locator
What does the URL contain?
The HTTP protocol, the domain name, and the file path.
The browser and sever communicate using what?
HTTP
What is web hosting?
A service where you place your website and files and the hosting company’s web server. Essentially renting the space for stables and secure storage.
What are the four kinds of web hosting?
Shared hosting, Virtual Private hosting, Dedicated hosting, and Cloud hosting.
What is the cheapest way of web hosting?
Shared hosting
How does Shared hosting work?
By renting a location on a web server containing many web hosting accounts. Meaning you share the servers processing power, memory, and bandwidth with other websites which can slow your performance.
Who is Shared hosting a good option for?
Small websites with a small amount of users and those looking for a low cost way to launch a website and play around with it.
What is a Virtual Private Server (VPS)?
A Virtual Server with dedicated CPU, Memory, and Bandwidth resources.
How does a VPS work?
Shared with other account but uses fixed resources for each account so your website is unlikely going to be impacted by the performance of others.
What is Dedicated hosting?
A hardware server for personal use.
What’s the benefit of using Dedicated hosting?
All CPU, Memory, and Bandwidth resources are yours to use.
Cloud Hosting is…
When your website runs in the cloud environment which spans across multiple physical and virtual servers. Causing your website to jump to another server if one fails.
The benefits of cloud hosting are…
You can use as many resources as you need without hardware limitations, you pay based on resource used, and allows you to scale your website as popularity grows.
Many major web applications operate using what kind of hosting?
Cloud Hosting
What is web acceleration?
When a server caches commonly requested content to speed up its delivery.
True or false? A web server can also be used to communicate between web clients and servers in local area networks such as a company’s intranet.
True
What does HTTP do?
Defines how text, images, and videos are transmitted on the web.
Web standards are…
Browsers operating identical enough to provide content in a similar fashion.
A rendering engine is used by the browser to…
Translate data into texts and images
What are hyperlinks?
URLs embedded into a webpage
URL is also known as what?
The web address
How do websites save information about you?
With cookies
We can modify our browsers using…
Extensions and add-ons
The internet is…
A whole bunch of computer networks connected to each other.
The first network experiment in the 1960s wasn’t about communication. It was about…
Optimizing processor usage, or time-sharing, so scientists could share computer power.
Our only source of computing before the 1960s was…
Mainframes
What allowed mainframes to start processing more than one task at a time?
Time-Sharing
What was the benefit of time-sharing?
It allowed multiple scientists to use a mainframes computing power at the same time.
Who came up with packet switching?
The British
Packet switching was revolutionary because…
It helped avoid congestion in busy networks by cutting up data at one end and putting it back together at the other.
The term internet was thought to be born when…
The French were working on a scientific network called CYCLADES and decide to work on direct connections between computers, as opposed to working on gateway computers.
What forms the basic communication language of the internet
TCP/IP protocols
What does the TCP/IP protocol do?
Labels the packets of data to make sure even though some pieces of data take a different route, they all arrive at their destinations and can be reassembled.
What year did networks begin to really communicate with each other?
- Arguably the beginning of the internet.
Email was developed for ARPANET in what year?
1972
The internet was mostly what in 1976?
Email traffic
Who invented the interface using HTTP, HTML and URLs that made internet browsers possible?
Timothy Berners Lee
Why did Timothy Berners Lee develop his interface
While spending time with LERN, the European Organization for Nuclear Research, he wanted to manage the scientists information and make it possible for them to share and interconnect their work easily, making progress more likely.
When was the first website created on the World Wide Web and by who?
1991 by Timothy Berners Lee
What year did the internet spread enough to become workable by the masses
1995
Who invented the internet?
Not one person in particular. It was many cool inventions that came together over time and helped create what we know today as the internet.
What engine does the chrome browser use?
The Blink Engine.
What is a browser engine (layout or rendering engine) ?
A core software component of every major web browser that’s used to transform html documents and other resources of a webpage into an interactive virtual representation on a users device.
A browser engine also…
Enforces the security policy between documents, handles navigation through hyperlinks and data submitted through forms, and implements the document object model (DOM) data structure exposed to page scripts.
The browser engine works in concert with…
The JavaScript engine
How a computer sends and receives data is similar to what?
The postal system
What makes it possible to send data across the internet?
Internet Protocol (IP) addresses
IP addresses function like…
Addresses in a postal system
Computers are…
Destinations that request and receive data
Networks are…
Routes that requested data travels across
IP version 4
192.0.2.235
IP version 6
4527:0a00:1567:0200:ff00:0042:8329:326b
Data is sent across a network as…
A series of messages called IP packets, also known as data grams.
High level IP packets contain…
A header and data. Just like an envelope has an address and a letter. As well as return addresses
Just like letters. IP packets can be delivered…
Out of order, damaged, or can become lost.
To solve delivery problems with IP packets…
The payload part of the packet contains other protocols. These are an extra message within the payload of an IP packet.
The two most common protocols used with IP are
Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)
TCP solves
IP packets becoming lost, damaged, or delivered out of order with the cost of a small delay when sending data.
UDP solves…
The corrupt packet issue but packets can still arrive out of order or not arrive at all.
TCP is used for…
Sending data that must arrive correctly and in order such as texts and image files.
UDP is used for…
Things like voice calls or live video streaming.
What does the lock icon beside the url mean?
That the secure version of HTTP is being used (HTTPS)
What is HTTP?
A core operational protocol of the World Wide Web that enables the web browser to communicate with a web server that hosts a website. It is the communication protocol we use when browsing the web.
What does an HTTP request consist of?
A method, path, version, and a header.
The HTTP method describes…
The type of action that the client wants to perform.
What are the most commonly used HTTP methods?
GET, POST, PUT, and DELETE.
What is the GET method used for?
Retrieving information from the server
What is the POST method used for?
Sending data to the server.
What is the PUT method used for?
Updating whatever currently exists on the website with something else.
What is the DELETE method used for?
Removing the resource.
What are the two most common versions of the HTTP protocol?
Version 1.1 and Version 2.0
What is the path?
The representation of where the resource is stored on the web server.
An example of a path is…
If you wanted to request an image from a page on a website then the URL in the address bar would need to contain the full path to that particular file on the web server
Example.com/images/image.jpg
What do headers do?
They contain additional information about the request and the client that’s making the request.
There are certain request methods that…
The requests will also contain a body of content that the client is sending.
True or false? HTTP responses follow a format similar to the requests.
True
An HTTP request and response format…
Following the header, the response will optionally contain a message body consisting of the response contents such as the HTML document, the image file, and so forth.
What indicates if the HTTP request is successfully completed?
HTTP status codes
The status message is…
The text representation of the status codes.
Two very common HTTP status codes are…
404 error not found & 500 error page not responding
What are the five groups of status codes
Informational, successful, redirection, client error, and server error.
Informational status code #s
100-199
Successful status code #s
200-299
Redirection status code #s
300-399
Client error status code #s
400-499
Server error status code #s
500-599
Informational responses are…
Provisional responses sent by the server that are interim before the actual response.
What is the most common informational response and what does it mean?
100 continue, which indicates the Web client should continue to request or ignore the response if the request is already reading finished.
What do successful responses indicate?
The request was successfully processed by the web server.
What is the most common successful response and what does it mean?
200 OK which is a response we receive everyday when we successfully receive content from a website.
What does OK mean when the method is GET?
The resource is found and included in the body of the HTTP response.
What does OK mean If the method is PUT or POST?
The resource was successfully transmitted to the web server.
What does OK mean if the method is DELETE?
The resource is deleted.
What do redirection responses indicate to the client?
That the requested resource has been moved to a different path.
What are the most common redirection responses?
301 moved permanently & 302 found
What is the different between 301 and 302?
302 means a temporary redirection.
What do client error responses indicate?
The request contained bad syntax or content and cannot be processed by the web server.
400 is used when…
The client submits bad data to the web server.
401 is used to…
Indicate the must login to an account before the request can be processed.
403 is used to…
Indicate the request was valid but the web server is refusing to process it ( often indicating the user does not have the sufficient permissions to execute an action in a web application)
404 is used to…
Indicate that the request resource was not found on the web server.
Server error responses indicate…
That a failure occurred on the web server while trying to process the request.
What is the most common server error response?
500 internal server error
500 internal server error is…
A generic error status indicating that the server failed to process the request.
What is HTTPS very useful for?
Things like securing credit card information used on a website.
What is HTTPS used for?
Secure communication between 2 computers so that nobody else can see the information being sent or received.
How does HTTPS secure communication?
Through encryption
How is HTTPS different than HTTP?
It turns information into secret code that only the other computer can read.
HTTP is a protocol used by web clients and web servers that is…
The foundation of any data exchanges on the web.
What is an example of an http request?
GET/home.html HTTP/1.1 this includes the method, the resource request, and protocol version in that order.
What is an HTTP header?
A case-insensitive name followed by a : and then followed by a value.
What does the host header do?
Specifies the host of the server and indicates where the resource is requested from.
What does the user-agent header do?
Informs the web server of the application that is making the request. Often including the operating system (Mac, windows, Linux) version and application vendor.
What does the accept header do?
Informs the web server what type of content the client will accept as the response.
What does the accept-language header do?
Indicates the language and optionally the locale that the client prefers.
What does the content-type header do?
Indicates the type of content being transmitted in the request body.
HTTP response headers
The date, server, content-length, and content-type
Date header
Includes the date and time the HTTP response was generated
Server header
Describes the web server software used to generate the response.
Content-length header
Describes the length of the response.
Content-type header
Describes the media type of the resource returned (e.g. html, document, image, video)
What is the aim of the HTTP response body?
To provide the client with the resource it requested, or inform the client that the action it requested has been carried out; or else to inform the client that an error occurred in processing its request.
What does html reference?
CSS and JavaScript
HTML is used on top of TCP to…
Transfer webpages and other content from websites.
Dynamic Host Configuration Protocol (DHCP)
Used to assign your computer an IP address when it connects to a network.
How does DHCP work?
Computers communicate over User Datagram Protocol (UDP) using a protocol with a type of server called a DHCP server. The server keeps track of computers on the network and their IP addresses. It will assign your computer to an IP address and respond over the protocol to let it know which IP address to use. Once your computer has an IP address it can communicate with other computers on the network.
Domain Name System Protocol (DNS)
Provides a way for your computer to know which IP address to communicate with when you visit a website in your web browser. After your computer does this is will check with the DNS server associate with domain name and then return the correct IP address.
Internet Message Access Protocol (IMAP)
Used to download emails and manage your mailbox on the server storing your emails.
Simple Mail Transfer Protocol (SMPT)
Allows email clients to submit emails for sending via an SMPT server. It can also be used to receive from an email client, but IMAP is more commonly used for this.
Post Office Protocol (POP)
An older protocol used to download emails to an email client.
What is the difference in using POP instead of IMAP?
POP will delete emails on the server once they have been downloaded to your local device but IMAP won’t.
Even tho POP isn’t commonly used in email clients, developers often use it to do what?
Implement email automation because it’s more straight forward than IMAP.
File Transfer Protocol (FTP)
A way to transfer the files from your local computer to the server they’ll run on. It allows you to list, send, receive, and delete files on a server.
Secure Shell Protocol (SSH)
The most common method of logging in and interacting with the computer remotely when working with servers. Using an SSH client allows you to connect to an SSH server running on a server to preform commands on the remote computer. All data sent over SSH is encrypted.
SSH File Transfer Protocol (SFTP)
Pairing SSH and FTP ensures that data using FTP is transmitted securely. FTP alone transmits data insecurely.
What is more informative than interactive? A website or webpage
A website is more informative.
Web applications
Highly interactive, have dynamically updated content, and have personalized results.
The Main developer tool functions in the browser are…
Elements, Console, Sources, Network, Performance, and Memory.
Console Function
Outputs JavaScript logs and errors from the web application.
Sources Function
Shows all content resolve for the current page. Includes html, css, JavaScript, images, and videos.
Network function
You can inspect the timeline and details of HTTP requests and responses for the webpage.
Performance function
Shows what the web browser is doing over time. Very useful if your web application is running slow because you can pinpoint the functions that are taking the most time.
Memory function
Displays the parts of your code that are consuming the most resources.
Elements function
The most used tab, used to inspect the documents, html elements, and their properties.
Why are the the web developer tools on our browser very effective?
They allow us to quickly inspect and diagnose problems.
Frameworks and libraries contain…
Key processes used everyday in software development
Open source means…
Freely available to anyone to edit and build from.
frameworks and libraries that are licensed and built internally are called what?
Proprietary frameworks and libraries.
True or false? Many developers use the terms framework and library interchangeably.
True
LIBRARIES
are full of Reusable pieces of code that can be used by your application and they are purpose built to provide a specific functionality such as validating email addresses, etc. They help save time.
FRAMEWORKS
provide a structure for developers to build with, just like builders use blueprints. They handle functionality common to all web applications such as receiving HTTP requests. The programmer then implant a their own code which defines the functionality of the application. They generally use many libraries and are considered opinionated.
Frameworks define…
The libraries, flow, and control of an application.
Framework advantages vs disadvantages
Time saving, structured, best practice vs. structure constraints, compatibility.
True or false? Some of the libraries the framework uses may conflict with a library that you are required to use and cause compatibility issues.
True
The upside to not using a framework is..
Replacing libraries is much easier than replacing a framework.
APIs are most likely being used when…
We access information like reading the news, purchasing something, or connecting with friends on social media.
What are APIs
Developer friendly, easily accessible, and very valuable/useful development tools. The are a service, application, or interface offering advanced functionality with some syntax.
What does API stand for?
Application Programming interface
The term API is…
Intentionally open to many applications and use cases.
True or false? A lot of the day to day job of a web developer involves working with APIs
True
3 common API that web developers work with are…
Browser API, RESTful API, and sensor-based API
Why do APIs get nicknamed middleware or gateways
Because APIs are often the bridge between different components or systems in software development.
Browser API/Web API
Built in to the browser and extend the functionality of the browser by adding new services. They are designed to simplify complex functions and provide easy syntax for building advanced features.
DOM API
Turns an HTML document into a tree of nodes which are represented as JavaScript objects.
Geolocation API
Returns the coordinates of where the browser is located.
Fetch API
For fetching data
Canvas API
For graphics
History API
For Keeping history
RESTful API
Provides data for popular web and mobile apps (“web servers”) and are critical for web development.
REST stands for…
Representational State Transfer
What is REST
A set of principles that help build highly efficient APIs
What is a main responsibly of RESTful APIs
Sending and receiving data to and from a centralized database.
Sensor-Based API
Actual physical sensors that are interconnected with each other; this is what the Internet of Things (IOT) is based on. The sensors can communicate through API and they track and respond to physical data. (Examples: Philip hue smart lights, Node Bots)
Server API
GET, POST, PUT, DELETE
API endpoint example
HTTP://example.com/?T=info
How do we create discoverable interfaces?
APIs using the REST principle and good design practice.
What do APIs use endpoints for?
To specify how different resources can be accessed. The endpoint is built in to the URL when accessing the API
What happens when the API endpoint is hit?
The API performs whatever server side processing is need to build the response.
Two most common endpoint response are../
Full webpages and a data form based on JavaScript called JSON
We often use APIs to..
Extend the abilities or systems or act as a bridge between different components.
What does IDE stand for?
Integrated Development Environment
What is an IDE?
The main tool in your toolbox as a developer. It is just like a text editor but for code.
Syntax highlighting
Improves the readability for developers and is built in to the IDE. Special keywords are highlighted in different colors to help differentiate them from basic syntax.
Some great features of an IDE are…
Error highlighting, autocomplete, intellisense, and refactoring.
Transport Layer Security (TLS)
A protocol by applications to communicate securely across a network. It prevents tampering with and eavesdropping on email, web browsing, messaging, and other protocols.
Proxies
A group of entities between servers and clients that perform different operations and act as gateways or caches.
There are more computers between a browser and server handling requests such as…
Routers, modems, and more; they are Hidden in the network and transport layer.
True or false? A web page isn’t a hypertext document
False.
What is load balancing?
When a collection of servers work together to provide the data requested.
What makes a proxy transparent
When they forward on the requests they receive without altering them in any way.
What make a proxy non transparent?
When they change the request in some way before passing it along to the server.
What are the numerous functions proxies can perform?
Caching (public or private), filtering (like an anti virus scan or parental controls), load balancing (to allow multiple servers to serve different requests), authentication (to control access to different resources), logging (allowing the storage of historical information)
What can make HTTP stateful?
Cookies
HTTP relies on what?
TCP. Which is connection-based
What is QUIC
A general-purpose transport layer network protocol that builds on UDP to provide a more reliable and efficient TLP
Who designed QUIC
Jim Roskind at Google
Common features controllable with HTTP are?
Caching, relaxing the origin constraint, authentication, proxy & tunneling, sessions.
HTTP flow
- Open a TCP connection 2. Send an HTTP message 3. Read the response sent by the server 4. Close or reuse the connection for further requests
What happens when HTTP pipelining is activated?
Several requests can be sent without waiting for the first response to be fully received.
HTTP message defined in HTTP/1.1 and earlier..
Are human-readable
Messages in HTTP/2 are…
Embedded into a binary structure, a frame, allowing optimizations like compression of headers & multiplexing.
What is the most commonly used API based on HTTP?
XMLHTTPRequest API which is used to exchange data between a user agent and server. The modern fetch API provides the same features with a more powerful and flexible feature set
What is a protocol?
A rule which describes how an activity should be performed, especially in the field of diplomacy.
Why is HTTP so successful?
Because it is relatively simple compared to most client/server protocols.
What is the key to designing protocols?
To think through all possible uses of the protocol and describe each scenario carefully.
Metadata
Data about data
Open Systems Interconnection (OSI) model
A more abstract model than TCP/IP that can be used to understand a wide range of network architectures.
What are the OSI model layers?
- Physical 2. Datalink 3. Network 4.Transport 5. Session 6. Presentation 7. Application
What is the TCP/IP model widely used to do? Compared to the OSI model
Guide implantation of TCP/IP network, hardware, and software while the OSI model can help us look at and compare a wide range of network architectures ranging from openly developed networks to proprietary vendor-specific networks.
