Imagine, you are learning to do the web. You have just built a small website using HTML / CSS (or the original website with NodeJS) and want to show to friends and others for suggestions and instructions.

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Image for post helps you to build a web right away by coding from a browser, no need to install any IDE

This seems easy but not simple:

  • You have to find a VPS or free host, then search for a domain name and connect the domain name to VPS
  • If your web needs some features like a microphone, webcam, you must install HTTPS, it’s not easy
  • Or you can build a web server or run the app locally, then use ngrok, …

I already clear the cache and reload the whole page.

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Picture 1: giant e-commerce Amazon and eBay

What technology do they use that can load so quickly?

It only took a few minutes to open the web to find out, but I got an answer that was both interesting, surprising, and extremely interesting.

Note: Because I don’t know what the back-end of Amazon/eBay or some eCommerce sites( which could load their sites under 1s) are, I can only predict the following 2 things about the back-end:*

  • HTML is cached in RAM of webserver or web application to minimize back-end load time (If the user is not logged in).
  • CDN system is located in many places to speed up the loading of resources (image, CSS…

We will learn about VPS, why programmers should buy a VPS, along with cool tricks we can do with it.

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Photo by Christina @ on Unsplash

What is VPS? What is the difference between VPS and host?

VPS (Virtual Private Server) is a virtual server on the network, provided by hosting service providers (Digital Ocean, Linode, Hostinger …)

Simply put, it is a server located on the network, with a pre-installed operating system (Ubuntu, CentOS). You can access the server with the highest root privileges, whatever you want.

Nowadays, when we want to put a website online, we often have to hire hosting. In essence, hosting and VPS are sharing resources on a pretty big server.

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However, hosting is like a dormitory (cheaper), you have to eat and drink in the same room with hundreds of people.

We will together learn techniques to crawler website data using DOM parsing technique using Nodejs.

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Photo by Carlos Muza on Unsplash

Perhaps you have heard about website crawling techniques somewhere. This is a fairly common technique for crawling; for example, the Google bot is also a form of crawler.

The crawler technique has many practical applications, which can include several ideas such as: Building a newspaper reader application by crawling website data from significant newspapers, crawling recruitment information from Facebook, etc.

There are many ways to create a web crawler, and there are also plenty of frameworks to support it. …

Here is a simple example to get some product data on amazon using python language.

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Photo by Christian Wiediger on Unsplash

Table of contents

  1. Install the environment
  2. Doing
  3. Conclusion

Crawl data from web pages is a not-so-unfamiliar concept to web programmers. However, after more than two years working as a programmer, I had my first experience crawling data, but also from a famous shopping site, Amazon.

There are many of you asking me to be a programmer, what do I do to crawl data from the Amazon website? …

In this article, I will talk about something quite simple in C #: Compare two objects. This is a problem that everyone thinks is easy; I will gradually raise the issue from simple to complex. The workaround will also go from simple to complicated, then back to simple. If you take the time to read this article from beginning to end, you will realize many things, and the technical ability will increase quite well.

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Photo by Luca Bravo on Unsplash

Level 1: Simple class

We start the problem with a simple class. …

In this article, I would like to present my understanding of asynchronous programming in C # and .Net.

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Photo by Patrick Tomasso on Unsplash

Table of contents

  • Asynchronous programming in C #
  • Highlights of Asynchronous Programming in C #
    1. Improve application performance
    2. Asynchronous methods in C # are easy to write
    3. Awaiting many asynchronous methods
    4. Canceling the task
    5. Parallel programming
    6. Asynchronous and threading
  • Conclusion

Asynchronous programming in C#

In many programming languages today, support for asynchronous programming has become quite popular. Asynchronous programming in C # is the same thing.

The most common example is communicating with the server via javascript Ajax. It can be understood; asynchronous programming is the ability to perform tasks independently. They do not have to run sequentially (can run in parallel) or one Thread without waiting for another to improve the performance of the application. …

Write to freelancers I love so much. I hope you can maximize your capacity.

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Photo by Fab Lentz on Unsplash

I graduated in 2005, came back to Vietnam in 2006; the Vietnamese stock market entered a boom period. At that time, financial graduates graduated “costly,” not only high salaries, respected, but many of them even dared to quit, invest, and “win” quite boldly on the stock market. Looking back 15 years, most of these quick friends, though very good, somehow lost both in financial markets and in other fields. …

XSS (Cross-Site Scripting) is a security bug that allows hackers to embed malicious code (javascript) on another website.

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This is one of the most common security flaws on Web sites. Systems from large to small such as Facebook, Twitter, … have been subjected to this error. Due to its popularity and danger, XSS is always honored to be in the top 10 most dangerous security flaws on OWASP (Open Web Application Security Project).

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Types of XSS

Previously, XSS often targeted HTML rendering code from the server-side, we called Server XSS. Two common types of XSS Server are Persistent XSS and Reflected XSS.

Here, I will take a young man named K as an example. …

After a hard time, I also completed the first lesson in the introductory security series. This article will discuss the “security” of the HTTP protocol.

The website of Lazada (e-Commerce) and ACB Bank ( Banking) in VietNam will be pulled as an example. Because the article is quite long, please slowly read it.

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Review on HTTP

HTTP is a protocol used to transmit data (See more here). Currently, most of the data on the Internet is sent via HTTP. Web or mobile applications also call the Restful API over HTTP.

However, the downside of HTTP is that data is transmitted in plain text, not encrypted or secure. This makes it easier for hackers to eavesdrop on, steal, and edit data. They call this type of attack Man-in-the-middle attack, abbreviated MITM. …



Always be nice to anybody who has access to my toothbrush.

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