Category: Computing

Adding virtual hosts on Bitnami Apache

Adding virtual hosts on Bitnami Apache

Over the weekend, I’ve spent a substantial chunk of time figuring out how to add a virtual host onto a client’s subdomain. In laymen’s terms, this means that:

  1. My client has a website hosted on a domain (which we shall call example.com, for confidentiality reasons)
  2. We want to build a web application on app.example.com, which will be entirely separate from example.com.
  3. To save on cost, we want to host app.example.com on the same server that example.com is using (i.e. create a virtual host on the web server).

This means that we have to configure our web server so that it will serve a different webroot depending on the domain it is being accessed from.

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Shallow vs. deep copying in Python

Shallow vs. deep copying in Python

If you’ve worked with Lists in Python before, you’ll quickly realise that they work differently from primitives like integers and strings. Consider the following:

a = "hello"
b = a
a = "world"
print(a) # Outputs world
print(b) # Outputs hello

Notice that changing the value of a does not change the value of b. This is called passing by value. In Python, Lists do not behave this way:

a = [2, 3, 4, 5]
b = a
a.append(6)
print(a) # Outputs [2, 3, 4, 5, 6]
print(b) # Outputs [2, 3, 4, 5, 6]

In the above example, notice that changing the value of List a also changes the value of List b. This is because both a and b are referring to the same List, and this is called passing by reference.

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Security for your Ubuntu Droplet

Setting up basic security for your Ubuntu Droplet

Have you recently spun up a new Ubuntu Droplet on DigitalOcean? The other day, when I checked my authentication logs in /var/log/auth.log, I came across several login attempts with random usernames.

Malicious login attempts in Ubuntu
Login attempts by malicious users.

We often take security for granted, but it becomes something of great concern once you start to manage servers of your own. If you were to leave your Droplet as it is, it is only a matter of time before hackers guess your login credentials and gain access to your system. Hence, here are some basic security measures you should set up to prevent others from breaking in:

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Swords and Shields
Awesome starters artwork by Ry Spirit: https://instagram.com/ryspiritart/

Calculating EVs needed to raise a stat in Pokémon

As a result of working on upgrades for this Pokémon Effort Value Calculator, math has been a pretty big part of my life for the past few months, as I’ve been rearranging the games’ formulas for stat and damage calculation to make my own that fit my needs.

One such formula was the EVs needed one, which gives you the amount of EVs you need to invest to raise a stat by n points. Everyone knows that at Level 100, you get 1 stat point for every 4 EV points you invest; but what happens when you’re not at Level 100, or when you factor in stat modifiers like Nature, or item and ability boosts?

Don’t know what effort values are? Start with this article from Bulbapedia. Don’t play the mainline Pokémon games? Then you should start with these.

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RAM in Black
Image by Tim Sullivan, from https://stocksnap.io/photo/computer-ram-IN0CFPMXAQ

RAM, explained in English

RAM stands for Random-Access Memory, but that is something that you can find out just by doing a quick Google search. If you read the results of said Google search to understand what it is, you’ll start running into jargon that can be difficult to understand for a layperson. Here are some examples:

…a form of computer memory that can be read and changed in any order, typically used to store working data and machine code

Wikipedia: https://en.wikipedia.org/wiki/Random-access_memory

…temporary storage that goes away when the power turns off

Avast: https://www.avast.com/c-what-is-ram-memory

…is used to load and run applications, such as your spreadsheet program, respond to commands, such as any edits you made in the spreadsheet, or toggle between multiple programs, such as when you left the spreadsheet to check email

Crucial.com: https://www.crucial.com/articles/about-memory/support-what-does-computer-memory-do

These are not bad examples, per se, but if you don’t work with computers a lot, these explanations will seem very abstract. What does working data mean, for example; or why is RAM temporary storage (why not just make it permanent)?

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