DEV Community: Harsha Vardhan

Are you preparing for your next frontend interview?

Harsha Vardhan — Wed, 21 Oct 2020 04:00:09 +0000

Here are some of my favorite resources which I always look up to for technical interviews.

Additional Resources to learn DATA structures,javascript..etc

USEFUL TIPS FOR BEGINNERS / DEVELOPERS

Harsha Vardhan — Thu, 15 Oct 2020 09:34:10 +0000

Learning path for all developers:

Tutorials to build your knowledge
Build project & apply your knowledge
Build more advanced projects if you can
Build your portfolio
Create Github account & push on Github
Practice interview questions
Apply for jobs
Repeat

Path for Web-Developers

Learn HTML, CSS and JavaScript.
Learn a framework or library( react, vue, angular are the trending at the moment )
Learn webpack.
Learn git.
Open a GitHub account.
Create a project and push it to GitHub.
Apply for a job.

Checklist for #CodeNewbies looking for jobs & internships -

A portfolio website & blog
knowledge of your fav. Tech Stack
1 page Résumé (pdf)
Realtime Projects
GitHub profile
Stack Overflow profile
Professional Email ID

How to become a better Programmer:

Get better at Googling
Find a mentor
Help others
Build side projects
Improve your soft skills
Keep learning
Master the skills you already have
Ask for help
Take regular breaks
Don't give up

AWS Cheatsheet

Harsha Vardhan — Sat, 10 Oct 2020 11:19:10 +0000

AWS Services CheatSheet

Cloud Cloud computing is becoming very popular nowadays and AWS has pioneered the market.

Most companies ask AWS related questions in interviews, so this blog explains the 40 most popular services offered by AWS

VPC - Virtual Private Cloud (VPC) lets you launch AWS resources in a private, isolated cloud.
Route 53 - It's a scalable and highly available DNS and domain name registration service.
EC2 - Amazon Elastic Compute Cloud (EC2) provides
resizable compute capacity in the cloud.
Elastic Beanstalk - AWS Elastic Beanstalk is an application container for deploying and managing applications.
Lambda - AWS Lambda is a compute service that runs
your code in response to events and automatically manages the computing resources.
EC2 Container Service - Amazon ECS allows you to easily run and manage Docker containers across a cluster of EC2 instances.
Mobile Hub - AWS Mobile Hub lets you quickly build, test, and monitor the usage of your mobile apps
Device Farm - Device Farm helps to improve the quality of Android, Fire OS, and iOS apps by testing them against real phones and tablets in the AWS Cloud
SNS - Simple Notification Service (SNS) lets
you publish messages to subscribers or other applications.
Cognito - Cognito is a simple user identity and data sync. service that helps to securely manage and synchronize app data for your users across their mobile devices.
Mobile Analytics - Mobile Analytics is a service that lets you easily collect, visualize, and understand app usage data at scale.
IAM - AWS Identity and Access Management (IAM)
lets you securely control access to AWS
services and resources.
Inspector -Amazon Inspector enables you to analyze the behavior of the applications you run in AWS and helps you to identify potential security issues.
Directory Service- AWS Directory Service provides managed directories in the cloud.
Certificate Manager - AWS Certificate Manager lets you easily provision, manage, & deploy SSL/TLS
certificates for use with AWS services.
WAF - Web Application Firewall protects
web applications from attack by providing web
traffic filtering against common web exploits.
GameLift - Deploy and scale session-based multiplayer games in the cloud in minutes, with no upfront costs.
S3 - Amazon Simple Storage Service (S3) can be
used to store and retrieve any amount of data.
Import/Export Snowball - AWS Import/Export Snowball accelerates moving large amounts of data into and out of AWS using secure appliances for transport.
Glacier - It is a low-cost storage service
that provides secure and durable storage for
data archiving and backup.
Storage Gateway - AWS Storage Gateway securely integrates on-premises IT environments with cloud storage for backup and disaster recovery.
CloudWatch - Amazon CloudWatch provides monitoring for resources and applications.
Config - AWS Config gives you an inventory of your AWS resources lets you audit resource configuration history & notifies you when resource configurations change.
CloudFormation - It lets you create & update a collection of related AWS resources in a predictable fashion.
API Gateway - Amazon API Gateway makes it easy to create, maintain, monitor, and secure APIs at any scale.
SQS - Amazon Simple Queue Service (SQS) offers a
reliable, highly scalable, hosted queue for storing messages.
CloudSearch - AWS CloudSearch is a fully managed search service for websites and apps.
RDS - Amazon Relational Database Service (RDS)
makes it easy to set up, operate, and scale
familiar relational databases in the cloud.
ElastiCache - ElastiCache improves application performance by allowing you to retrieve information from an in-memory caching system.
DynamoDB - DynamoDB is a scalable NoSQL data store that manages distributed replicas of your data for high availability.
Redshift - It is a fast, fully managed, petabyte-scale data warehouse that makes it cost-effective to analyze all your data using your existing business intelligence tools.
SES - Amazon Simple Email Service (SES) enables
you to send and receive an email.
CodeCommit - AWS CodeCommit is highly scalable,
managed source control service that hosts private Git repositories.
CodeDeploy - AWS CodeDeploy lets you fully automate code deployments
AWS IoT - AWS IoT is a managed cloud service that lets connected devices easily and securely interact with cloud applications and other devices.
Machine Learning - Amazon Machine Learning is a service that enables you to easily build smart applications.
Data Pipeline - AWS Data Pipeline is a lightweight
orchestration service for periodic, data-driven workflows.
Kinesis - Amazon Kinesis services make it easy to work
with real-time streaming data in the AWS cloud.
WorkSpaces - Amazon WorkSpaces is a fully managed desktop computing service in the cloud.
WorkMail - Amazon WorkMail is a managed email and calendaring service that offers strong security controls and support for existing desktop and mobile clients.

Credits:- mayank

Useful resources for web developers🖥

Harsha Vardhan — Thu, 08 Oct 2020 07:14:30 +0000

🔨50+ free tools and resources to create awesome user interfaces 👇

1.Photos & Videos 👇
https://coverr.co/
https://mixkit.co/
https://www.pexels.com/
https://photos.icons8.com/creator
https://www.unscreen.com/
https://www.remove.bg/
https://generated.photos/faces
https://duotone.shapefactory.co/

2.Illustrations 👇👇

https://www.openpeeps.com/
https://usesmash.com/
https://opendoodles.com/
https://control.rocks/
https://icons8.com/ouch
https://getavataaars.com/
http://knutsynstad.com/fauxcode/

3.Palette👇👇

https://colormixer.web.app/02007115ff623007ff9bc91b64440301ffff7c5f55610300/Sunset
https://cssgradient.io/
https://colorsinspo.com/
https://www.colorhexa.com/index.php
https://mycolor.space/
https://palettte.app/
https://colorable.jxnblk.com/

4.Typography 👇👇

https://freebiesbug.com/free-fonts/
https://fontsarena.com/
https://befonts.com/
https://www.fontsquirrel.com/
https://fontjoy.com/
https://type-scale.com/

5.Animations & Effects 👇👇

https://brumm.af/shadows
https://emilkowalski.github.io/css-effects-snippets/
https://wweb.dev/resources/css-separator-generator
https://animista.net/
https://shopify.github.io/draggable/
https://tympanus.net/Development/BlockRevealers/index.html

6.Iconography 👇👇

https://iconstore.co/
https://css.gg/
https://nucleoapp.com/tool/icon-transition
https://tilda.cc/free-icons/
https://ikonate.com/
https://akveo.github.io/eva-icons/#/
https://icons8.com/animated-icons

7.Patterns & Shapes 👇👇

https://bansal.io/pattern-css#triangles
https://getwaves.io/
https://www.blobmaker.app/
https://msurguy.github.io/rad-lines/
https://products.ls.graphics/paaatterns/
https://www.scribbbles.design/

8.Utility 👇👇

https://nucleoapp.com/
https://www.checklist.design/
https://designsystemsrepo.com/design-systems-recent/
https://csspeeper.com/
https://icons8.com/upscaler

Back-end Developers RoadMap❤

Harsha Vardhan — Sun, 27 Sep 2020 11:19:32 +0000

Roadmap for Back-End Developers💕

Internet

How does the internet work?
What is HTTP?
Browsers and how they work?
DNS and how it works?
What is Domain Name?
What is hosting?

Basic Front-end Knowledge

HTML
CSS
JavaScript

OS and General Knowledge

Terminal usage
How OSs work in general
Process Mgt.
Threads & concurrency
Basic terminal commands
Memory mgt.
Interprocess comm.
I/O mgt.
POSIX basics
Basic networking concepts

Learn a Language

Make sure to learn it fast and clear. Core details about its runtime e.g concurrency, memory model etc.

Java
Python
PHP
C#
Javascript
Ruby
Rust
Go

Version Control System

Basic usage of Git
Repo hosting services
I. GitHub
II. Gitlab
III. Bitbucket

Relational Databases
MySQL
PostgreSQL
MariaDB
MS SQL
Oracle

NoSQL Databases

MongoDB
RethinkDB
CouchDB
DynamoDB

More About Databases

ORMs
ACID
Transactions
N+1 Problem
Data Replication
Sharding Strategies
CAP Theorem
Database Normalisation
Indexes and how they work

Learn About APIs

REST
JSON APIs
HATOAS
Open API Spec and Swagger
Authentication
GraphQL

Caching

CDN
Server-side I. Redis II. Memcached
Client-side

Web Security Knowledge

Hashing Algorithm
- MD5 and why not to use it
- SHA Family
- Scrypt
- Bcrypt
HTTPS
Content Security Policy
CORS
SSL/TLS
OWASP Security Risk

Testing

Integration Testing
Unit Testing
Functional Testing

CI/CD

Jenkins
GitLab
CircleCI
Bamboo
TeamCity
Travis CI
Buddy

Design and Development Principles

SOLID
KISS
YAGNI
DRY
GOF Design Patterns
Domain-Driven Design
Test-Driven Development

Architectural Patterns

Monolithic
Microservices
SOA
CQRS and Event Sourcing
Serverless

Message Brokers

RabbitMQ
Kafka

Containerization

Docker
rkt
LXC

Web Servers

Nginx
Apache
Caddy
MS IIS

Building For Scale

Migration Strategies
Horizontal vs Vertical Scaling

Front_END Web developer Roadmap

Harsha Vardhan — Mon, 21 Sep 2020 10:37:13 +0000

Complete Front end web development roadmap

HTML

learn the basics
Forms and validations
Accessibility
SEO
Convention and best Practices

Web Components

HTML elements
Custom elements
Shadow DOM

CSS

Learn the basics
Responsive Design
Making layouts
- Floats
- Positioning
- Display Box
- Model CSS
- Grid
- FlexBox

CSS Architecture

BEM
OOCS
SMACSS

CSS Preprocessor

Sass
Postcss
Less

CSS FrameWorks

CSS first Frameworks
- Bootstrap
- Materialise CSS
- Bulma
- JS Based Framework
- Reactstrap
- Material Ui
- Tailwind CSS
- Chakra UI

Modern CSS

Styled Component
CSS MOdules
Styled JSX
Emotion
Radium
Glamorous

Javascript

Syntax and Basic Construct
Learn DOM manipulation
Learn Fetch API/ Ajax
ES6+
Modular javascript
Understand below Concepts
- Closures
- Scope
- Async await
- Prototype
- Event Bubbling
- Shadow DOM
- Hoisting
- Strict ...etc *....And many more

JS Framework

React js
- MobX
- ReduX
Vue js
- VueX
Angular
- RxJS
- NgR

Type checkers

Typescript
Flow

Progressive Web Apps(PWA)

Storage
web Sockets
Service Workers
Location
Notification
Device Orientation
Payments
Credentials
Accelerated Mobile pages (AMP)

Perfomance

PRPL Pattern
RAIL Model
Perfomance
Metrics
Using LightHouse
Using DevTools

Server Side Rendering (SSR)

React js
- Next.js
- After.js
- Angular
- Universal
Vue.js
- Nuxt.js

GraphQL

Apollo
Relay Modern

Static site generators

Next.js
Gatsby.js
Nuxt.js
Vuepress
jekyll
Hugo

Mobile Applications

ReactNative
NativeScript
Flutter
Ionic

Desktop Applications

electron
Carlo
Proton Native

Pacakage Managers

npm
Yarn

Test your apps

Jest
React-testing-library
cypress
enzyme

Build Tools

Linters and formatters
- Prettier
- ESLint
- StandardJS

Module Bundlers

Webpack
Rollup
Parcel

web security Knowledge

Owasp top 10
CORS
HTTP
CSP(Content Security policy)

Note:- You don't need to learn all the above things..
Pick some of them and master them

Some useful websites for resources

Useful Cheatsheets for web developers & designers

Harsha Vardhan — Fri, 18 Sep 2020 06:15:51 +0000

Useful cheatsheets that must be in your basket

https://alialaa.github.io/css-grid-cheat-sheet/

https://reactcheatsheet.com/

https://www.supremo.co.uk/typeterms/

https://www.sketchingwithcss.com/samplechapter/cheatsheet.html

https://moz.com/blog/seo-cheat-sheet

https://shortcuts.design/

https://gitsheet.wtf/

https://github.com/LeCoupa/awesome-cheatsheets

http://www.storiesinflight.com/html5/

https://easings.net/en

https://fontawesome.com/cheatsheet

https://mbeaudru.github.io/modern-js-cheatsheet/

Preparation plan for placement interviews

Harsha Vardhan — Wed, 16 Sep 2020 10:54:51 +0000

3 Months interview preparation schedule

Week 0: Programming language

Week 1, 2 & 3: Data Structures

Week 4, 5 & 6: Algorithms

Week 7 & 8: System Design

Week 9 : Operating System

Week 10: Object-Oriented Design

Week 11: Database management

Week 12: Revision.

Programming language -

The best programming language for your #coding interviews is the language that
you’re most comfortable with. Prefer - #Java or CPP or #Python or #javascript

Brush up all the concepts of the #programming language of your choice.

Data Structures

Start by revising Computer Science Data Structures concepts.

Complexity Analysis (a.k.a BigO)
Arrays
Stacks
Queues
Linked List
Trees
Tries
Graphs (BFS and DFS)
Hash Tables
Heaps

Algorithms

Next, start by revising the most asked algorithms and the problems based on them.

Searching and Sorting
Greedy Algorithms
Dynamic Programming
Pattern Searching
Other String Algorithms
Backtracking
Divide and Conquer

Searching Algorithms for an interview

Linear Search
Binary Search
Jump Search

Sorting Algorithms for an interview

Selection Sort
Bubble Sort
Insertion Sort
Merge Sort
Quick Sort
Heap Sort
Counting Sort

System Design -

System Design Basic Concepts

Network Protocol
Horizontal & Vertical Scaling
Cache
Load Balancers
Content Delivery Network (CDN)
Reverse Proxy
Message Queue
Consistent Hashing
Database Sharding

System Design -

Large System Architecture

Design Url Shortening Service (ex – bitly)
Design Pastebin Architecture
Desing Rate Limiter
Parking Lot System
WhatsApp
Uber design
Instagram
Tinder Service

Operating Systems -

Threads
Locks
Synchronization
TLB
Interrupt vs System Call
Kernel
Round Robin Algorithm
Threads
Concurrency
Paging
Page Replacement Algorithms
Interrupts
Scheduling

Database Management System:

Introduction to DBMS
Database Architectures
ER Model, Relational Model 4.Keys in Relational Model
Database Normalization
Normal Forms
Concurrency Control
Indexing in Database
B+ Tree Introduction and SQL.

Object-Oriented Design -

Class & Objects
Polymorphism
Abstraction
Inheritance
Encapsulation
Practice Questions
- Design an ATM.
- Design an elevator.
- Design a Parking System.

Resources to follow for Coding interview Preparation -

...

Revise Core CS topics also

1. Compiler design
2. Theory of computation
3. Discrete Mathematics
4. Microcontrollers/Microprocessors
5. Computer Architecture
6. software engineering
7. Computer networks
8. DBMS

Some useful links/resources

Web server PenetrationTesting checklist

Harsha Vardhan — Sun, 30 Aug 2020 04:01:15 +0000

Web server pentesting performing under 3 major category which is identity, Analyse, Report Vulnerabilities such as authentication weakness, configuration errors, protocol Relation vulnerabilities.

“Conduct a serial of methodical and Repeatable tests “ is the best way to test the web server along with this to work through all of the different application Vulnerabilities.

2.“Collecting as Much as Information” about an organization Ranging from operation environment is the main area to concentrate on the initial stage of web server Pen testing.

3.Performing web server Authentication Testing, use Social engineering techniques to collect the information about the Human Resources, Contact Details, and other Social Related information.

4.Gathering Information about Target, use whois database query tools to get the Details such as Domain name, IP address, Administrative Details, autonomous system number, DNS etc.

5.Fingerprint webserver to gather information such as server name, server type, operating systems, an application running on the server etc use fingerprint scanning tools such as, Netcraft, HTTPrecon, ID Serve.

6.Crawl Website to gather Specific information from web pages, such as email addresses

7.Enumerate web server Directories to extract important information about web functionalities, login forms etc.

8.Perform Directory traversal Attack to access Restricted Directories and execute the command from outside of the Web server root directories.

Performing vulnerability scanning to identify the weakness in the network use the vulnerability scanning tools such as HPwebinspect, Nessus . and determine if the system can be exploited.
Perform web **cache poisoning attack to force the web server’s cache to flush its actual cache content and send a specifically crafted request which will be stored in the cache.
Performing HTTP response splitting attack to pass malicious data to a vulnerable application that includes the data in an HTTP response header.
Bruteforce SSH,FTP, and other services login credentials to gain unauthorized access.13. Perform session hijacking to capture valid session cookies and ID’s,use tools such as Burb suite , Firesheep ,jhijack to automated session hijacking.
Performing a MITM attack to access sensitive information by intercepting the communications between the end-users and web servers.
Use tools such as Webalizer, AWStats to examine the web server logs .

Important Checklist Suggested by Microsoft

Services

Unnecessary Windows services are disabled.
Services are running with least-privileged accounts.
FTP, SMTP, and NNTP services are disabled if they are not required.
Telnet service is disabled.

Protocols

WebDAV is disabled if not used by the application OR it is secured if it is required.
TCP/IP stack is hardened
NetBIOS and SMB are disabled (closes ports 137, 138, 139, and 445).

Accounts

Unused accounts are removed from the server.
6 Guest account is disabled.
IUSR_MACHINE account is disabled if it is not used by the application.
If your applications require anonymous access, a custom least-privileged anonymous account is created.
The anonymous account does not have write access to Web content directories and cannot execute command-line tools.
Strong account and password policies are enforced for the server.
Remote logons are restricted. (The “Access this computer from the network” user-right is removed from the Everyone group.)
Accounts are not shared among administrators.
Null sessions (anonymous logons) are disabled.
Approval is required for account delegation.
Users and administrators do not share accounts.
No more than two accounts exist in the Administrators group.
Administrators are required to log on locally OR the remote administration solution is secure.

Files and Directories

Files and directories are contained on NTFS volumes
Web site content is located on a non-system NTFS volume.
Log files are located on a non-system NTFS volume and not on the same volume where the Web site content resides.
The Everyone group is restricted (no access to \WINNT\system32 or Web directories).
Web site root directory has denied write ACE for anonymous Internet accounts.
Content directories have deny write ACE for anonymous Internet accounts.
Remote administration application is removed
Resource kit tools, utilities, and SDKs are removed.
Sample applications are removed

Shares

All unnecessary shares are removed (including default administration shares).
Access to required shares is restricted (the Everyone group does not have access).
Administrative shares (C$ and Admin$) are removed if they are not required (Microsoft Management Server (SMS) and Microsoft Operations Manager (MOM) require these shares).

Ports

Internet-facing interfaces are restricted to port 80 (and 443 if SSL is used)
Intranet traffic is encrypted (for example, with SSL) or restricted if you do not have a secure data center infrastructure.

Registry

Remote registry access is restricted.
SAM is secured (HKLM\System\CurrentControlSet\Control\LSA\NoLMHash).

Auditing and Logging

Failed logon attempts are audited.
IIS log files are relocated and secured.
Log files are configured with an appropriate size depending on the application security requirement.
- Log files are regularly archived and analyzed.
- Access to the Metabase.bin file is audited.
- IIS is configured for W3C Extended log file format auditing.

Server Certificates

Ensure certificate date ranges are valid.
Only use certificates for their intended purpose (For example, the server certificate is not used for e-mail).
Ensure the certificate’s public key is valid, all the way to a trusted root authority.
Confirm that the certificate has not been revoked.