D Guides

Have you ever wonder when you deploy an app into cloud how exactly it is hosted in cloud? Or maybe is it safe to host an app in cloud and how they maintain high availability?This post will clear  all your doubts  and free your mind. What is a Datacenter? Inside of a Datacenter Azure Datacenter is the smallest node or the exact physical location where our resources reside.But datacenters are not exposed to end users.These datacenters act exactly as the on premises servers.But since these datacenters are cloud datacenters you have extra capabilities which will help you grow with the customer base (Scale Up) or vice versa (Scale Down) for a lower cost than creating and maintaining own servers. Curious about Azure Regions ? Azure has more Regions than any other cloud provider.If you want the exact numbers there are 58 global regions and a region is a set of datacenters inside a latency defined perimeter.Most of the time we deal with these region when we ...

Welcome back to D Guides folks.This post is valuable for newbies for react development.I am sharing about few tools you can use when developing react applications.It is important leaning tools like these same as understanding a framework like React.These tools will help us to maintain high code quality. 1. Prettier Prettier is a tool which will format the code consistently according to the standards.First step to do is install prettier as a developer dependency.Why developer dependency is the next question hops into your mind.We don't need to have prettier as a dependency when we are deploying the application so that is why it is installed as a developer dependency.Then we need to install prettier plugin for vs code.VS Code is my first choice when doing web development.Then we are changing two things in preferences.First thing is enabling format on save.Other option we are enabling is require config.By that we ensure that prettier will run only on the projects prettier h...

Even though you are a beginner for node js you all know that Node.js is single threaded.But we use Node.js for powerful backends and we can include concurrence functionality into a Node.js application using events and call backs.In simple terms 'Event Loop' is what permits Node.js to perform non blocking I/O operations.Node.js uses event in large scale and it is the reason behind the speed when comparing to other technologies in the same stack What exactly is 'Event Loop' ? Everything happens in Node.js platform is because of events.'Event Loop' mechanism is inside the library called 'Libuv'.Since there is only one thread both userland code (code of the user) and event loop run in that same thread.Every callback is handled by the so called mechanism 'Event Loop'.Every userland code running in a Node application is a callback.Event Loop is behind the huge success of Node.js development.As I mentioned earlier every Node application i...

Welcome back to D Guides folks.I am breaking the radio silence after several months and I am hoping to update my 'Programming Guides' section on a weekly basis.Today I am sharing about an interesting topic but at first glance it may look like a monster.But it is not.Do you know what is 'Elasticserach'?Elasticsearch is a document oriented database which will store data in JSON document form.Basically it is a search index or a search engine.As the word 'Elasticsearch' implies this concept is to analyse and search your data in real time.The link below will take you to the official documentation of Elasticsearch. Elasticsearch Official Documentation There is another thing called 'ELK' stack which is the acronym for three open source projects:  Elasticsearch , Logstash and Kibana . As I mentioned earlier Elasticsearch will help you to store,analyse and search data in real time. Kibana is a platform to visualise data you feed in to Elasticsear...

Welcome back to D Guides.I am Sadeepa Gayashan and I am the newly joined contributor of D Guides.I will share my knowledge on cyber security through Cyber Guides of this blog.Today I am going to share with you how steal session cookies.Most web applications maintain a user session to identify the user across multiple HTTP requests. Sessions are identified by session cookie.After a successful login server will send you a session cookie by the Set-Cookie   header.We can steal the session cookie by calling document.cookie . For demo purposes, we will use the DVWA Application. First, we need to run DVWA as a server in localhost or in VirtualBox in our web browser.Now login with Username: admin, Password: password.  this is the interface of the web application.Once logged in, we want to navigate to the DVWA Security tab, select the security level in the drop-down box, and hit Submit 1. Set security low Then we need t...

Welcome back to D Guides. I decided to educate you about new releases and updates of mobile phone manufacturing giant 'Apple' since yesterday they held their launch event for the year 2019. If you are a regular visitor of my blog you can remember that I have written a post about the event took place in 2018 as well. If you have not read it, read it by the link given below. https://dwguides.blogspot.com/2018/09/what-happened-in-apple-event-2018.html Enough beating around the bush. Let's go straight into serious business. What exactly happened in the event? If you are a die-hard fan of Apple products as some of my friends ; ) you have definitely watched the whole event live. If you want to watch the event please visit the official youtube channel of Apple. The  event took place on 10th September 2019 at Steve Jobs Theater. I started writing this post right before they start the live streaming the event. Apple Arcade They first introduced the new Apple...