Blog on Akshay Raj Gollahalli

Tauri 2 With Flutter: A Template

Sun, 22 Dec 2024 23:38:20 +1300

The template can be found at akshaybabloo/tauri_flutter_template

Setting Swapfile on Ubuntu

Wed, 08 May 2024 13:26:07 +1200

When you are running out of memory on your Linux system, the OS starts killing processes to free up the memory. This is not a good idea, as it can lead to data loss. To avoid this, a swap file is used. By default, Ubuntu creates a swap file during installation. However, if you want to create a new swap file or change the size of the existing swap file, you can do so by following the steps below.

Running OpenCV with CMake and Ninja

Sun, 24 Mar 2024 14:53:40 +1300

INFO

Code can be found at https://github.com/akshaybabloo/opencv-cmake-ninja.

This post assumes that you have already built OpenCV with Visual Studio and CMake CLI or CMake GUI. If not, please refer to Build OpenCV With Visual Studio and CMake CLI or Build OpenCV With Visual Studio and CMake GUI.

Using QAbstractListModel With QML ListView in Qt6

Sun, 08 Oct 2023 21:22:52 +1300

INFO

The code can be found at https://github.com/akshaybabloo/qabstractlistmodel-with-qml-listview

This blog is going to be big!

Ever found yourself working on a project, wanting to combine the power of C++ with the flair of a QML ListView? That was me not too long ago. I thought diving into this would be straightforward, but as I dug deeper, I realised there were some gaps in available resources, especially when it came to dynamically handling lists.

Importing Existing Project to STM32CubeIDE

Thu, 03 Aug 2023 21:43:05 +1200

Let’s get one thing straight: I’m not the biggest fan of the Eclipse IDE. There, I’ve said it. In my view, Eclipse tends to overcomplicate tasks and create unnecessary obstacles for users just starting out. However, given that STM32 has chosen to tightly integrate their tools with their Eclipse-based IDE - STM32CubeIDE - I find myself using it regardless. While alternatives like VSCode or CLion are available, that’s not the focus of this post.

Build OpenCV With Visual Studio and CMake CLI

Wed, 17 May 2023 10:58:20 +1200

In the previous post, we have seen how to build OpenCV with Visual Studio and CMake GUI. In this post, we will see how to build OpenCV with Visual Studio and CMake CLI.

Compared to the previous post, this should be straight forward. We will be using the same CMake settings as before. The only difference is that we will be using the CMake CLI instead of the GUI and we will also use Ninja.

Helpful Powershell Cmdlets/Functions

Sun, 26 Feb 2023 12:02:06 +1300

These are some of the PowerShell cmdlets that I have found useful. I will be adding more as I find them. I usually add them to my PowerShell profile so that I can use them anywhere. To get the path of your PowerShell profile, run the following command:

> $profile
C:\Users\<user>\Documents\PowerShell\Microsoft.PowerShell_profile.ps1

Don’t forget to restart PowerShell after adding the cmdlets to your profile.

Table of Contents

List all USB devices
Get the size of a folder
List PATH environment variable
Print environment variables

List all USB devices

function Get-UsbDevices { 
 Get-PnpDevice -InstanceId 'USB*' -Class 'USB' -Status OK 
}
Set-Alias -Name lsusb -Value Get-UsbDevices

Get the size of a folder

This is a recursive function that will get the size of a folder in MB with 2 decimal places.

Build OpenCV With Visual Studio and CMake GUI

Sat, 25 Feb 2023 12:15:12 +1300

If you want to use the command line approach, check out my other blog - Build OpenCV With Visual Studio and CMake CLI.

If you have ever used OpenCV, you would know that it is a very powerful library for image processing. This is owing to ease in usage and availability of multiple functions which can be utilised to perform a variety of image processing tasks. In this post, we will explore the steps on how to build OpenCV with Visual Studio and Cmake GUI.

git-alias: Over Engineered Pretty Git Alias Printer

Tue, 06 Dec 2022 23:02:37 +1300

The binary files and the code can be found at github.com/akshaybabloo/git-alias.

Now there are different ways to list all the aliases in git. One of the ways is to use the command git config --get-regexp alias which will list all the aliases in the following format:

alias.la !git-alias

But is it pretty, though? No. So, I decided to use Go language to make it look 😍.

If you don’t know Go language, it’s a programming language developed by Google. It’s a compiled language and it’s pretty fast. It’s also easy to learn. I would recommend you to learn it if you are interested in programming.

dnode: Search and Delete Node Modules Folders Recursively

Tue, 17 Aug 2021 12:41:03 +1200

Source: github.com/akshaybabloo/dnode

Node’s package managers makes it easy to develop applications, but the bloat it brings with it is (that’s node_modules) painful. My 2013 Mac with 256 GB HDD cannot handle it. I currently have around eight projects that use yarn package manager and the total size of all node_modules comes to around ~2.2GB. And lets not even get to the cache folder (Tip: yarn cache clean). All the hate for node_modules is totally justified.

uHugo: A CLI Tool for Hugo Static Site Generator

Sat, 10 Jul 2021 21:25:21 +1200

uHugo is a CLI utility tool written in Python for maintaining Hugo binary files. You might think “Wait! don’t we have Homebrew, Chocolatey, Snap and a plethora of other tools for this?” that’s exactly why, and also they are package managers. uHugo takes it to the next step by not only updating your Hugo binary file to the version you need, but also updates cloud provider’s environment variables or configuration files. For example, Cloudflare Pages has a CI/CD system that builds and uploads the files to their storage place, but you will need to specify which version of Hugo you want to used to build these files. Some static host providers have configuration files to specify the version name, whereas Cloudflare Pages don’t; you will need to specify the Hugo version under their environment variable section.

Cookiecutter Template for Writing Go Command Line Interface

Sun, 27 Jun 2021 18:25:31 +1200

I have been developing a lot of Go language based CLIs and most of them have similar structure. And every time I start a new project I tend to rewrite the same structure. So, instead of doing that I copied the required code and turned in into a cookiecutter template 😎.

The repository is available at - github.com/akshaybabloo/go-cli-template.

This template is highly inspired by GitHub’s CLI.

Requirements

Python 3.6+
1. Install cookiecutter
Go 1.16+

Usage

In your terminal type in

Setting Azure AD B2C Authentication in Postman

Thu, 04 Mar 2021 16:20:34 +1300

Azure AD B2C has been so far good, mostly because of the 50k free user authentication 😇, also it just works. The problem I had using B2C with backend was acquiring and testing tokens in development.

Yes, Azure AD B2C has Resource Owner Password Credential (ROPC) flow that allows you to get tokens by just posting your username and password, but they don’t recommend it. Though, I have been using that locally to get the tokens.

Creating Custom Widget for QListWidget in Qt 6

Sat, 02 Jan 2021 16:44:41 +1300

With the arrival of Qt 6 and the complete integration of CMake, I wanted to give Qt another try before I give up and go to Electron. So far it has been good.

I have been trying to create an app that uses QListWidget with custom widgets as a list, to list recently viewed files. The custom widget contains a label and a button, this button deletes itself on clicking. I had trouble connecting the child widget to the parent, and if you had the same problem then this article could help you.

Mongo: A MongoDB Helper for Go Language

Mon, 01 Jun 2020 19:50:00 +1200

I am an avid user of MongoDB; I have used it everywhere from saving machine learning parameters to storing financial details. I have recently moved to Go language from Python/C++ and at the time of writing this article, MongoDB had its package for Go language - mongo-go-driver.

Traditionally, whenever we create a document in a collection, the database creates a unique ID - _id (more on that here), this field is of type ObjectID. ObjectID is a hexadecimal string that contains - 4-byte of timestamp value, 5-byte of a random value, 3-byte of incrementing counter.

Stopping HTTP Server Gracefully: Context vs Channels vs SyncGroup

Sun, 02 Feb 2020 13:01:03 +1300

Complete code can be found at github.com/akshaybabloo/gracefully-exit-go-http-server

I am developing a CLI application that requires it to authenticate and obtain a token from an API. I had a problem of gracefully shutting down the HTTP server from another function (handle), in this case, after a token is received. Go 1.8 introduced Shutdown that gracefully shuts down the server without interrupting any active connections.

In this post, we will look at using three ways to tell the server to shut down gracefully. Also, I am using Gorilla’s mux router.

dotnetcore: A .Net Core SDK Uninstaller for POSIX (now with Windows support)

Fri, 19 Jul 2019 17:09:20 +1200

There is no official way to uninstall previous versions of .Net Core SDK on POSIX type operating systems, this tool may help you solve that problem.

In Windows this tool can help you launch uninstaller as easy as writing a command line.

The repository can be found at https://github.com/akshaybabloo/dot-net-core-uninstaller.

Note: You might need super user account to use this library.

Instillation

pip install dot-net-core-uninstaller

Usage

There are to ways to use this:

Using SLF4J With Apache Log4j: An Example

Fri, 07 Jun 2019 11:56:12 +1200

Logging is essential when developing a software to keep a track on what is happening internally. This blog will show you how to use SLF4J with Apache Log4j.

1. Requirements
2. What is logging?
3. What is Log4J?
- 3.1. Why use Log4J when Java has java.util.logging?
4. What is SLF4J?
- 4.1. Why use SLF4J when Log4J has different types of log levels?
5. All about log4j2.xml

1. Requirements

This example assumes that you are familiar using Maven dependency manager. All the dependencies are listed in pom.xml

azsecrets: A CLI to Set Azure Key Vault as Environment Variables

Sat, 13 Apr 2019 18:05:05 +1200

Repository: https://github.com/akshaybabloo/azsecrets Documentation: https://akshaybabloo.github.io/azsecrets/

Using environment variables to store your secrets is one of the more natural way to do; these variables then can be used in your code throughout the life cycle of your Docker environment. You shouldn’t hard code your secret keys inside your application; it is just not secured. Docker lets you add the environment variable before creating an image or at the entry point when starting up your image, azsecrets lets you set these environment variables that are stored in Azure Key Vault.

Splitting Django Settings for Local and Production Development

Thu, 04 Apr 2019 23:37:42 +1300

I have been working on a few projects that use Django 2+ and deploying them to Azure Docker container. I do have one problem though; my development settings are very much different from my production. So, I have divided settings.py into a package with - base.py, local.py and production.py:

<project name>
├── <project name>
│   ├── __init__.py
│   └── settings
│      ├── __init__.py
│      ├── base.py
│      ├── local.py
│      └── production.py
└── .dockerignore

`.dockerignore` file

While building a container, the CLI looks for .dockerignore file, which contains the file or file pattern to be ignored before sending the information to the Docker daemon. We can compare this to .gitignore, that ignores any file mentioned in this before committing into the version control.

Setting Up Powershell Core in Visual Studio Code for macOS

Mon, 03 Dec 2018 10:30:16 +0530

Things we need:

Apple computer/laptop running macOS 10.14 (yes, the expensive one)
Ruby (it’s pre-installed on macOS, I have 2.3 pre-installed)
Homebrew
Visual Studio Code
Patience to do this :)

If you are NOT a newbie, jump to Step 4.

1. Installing Homebrew

Open Terminal and copy the link from the Homebrew website, this will install all the necessary packages and everything nice. Easy as.

2. Installing Visual Studio Code

Goto Visual Studio Code website, click on the big, obvious, button to download the DMG package. Open the package and copy it to Application folder. Again, easy as.

Spark: A Hugo Theme for Researchers

Sun, 14 Oct 2018 19:07:26 +1300

Hugo is a super fast static site generator with more than 500 contributors. Companies such as 1Password, Kubernetes and Cloudflare rely on Hugo to generate their documentation. Even this website is generated using Hugo.

There are a number of themes out there for companies, bloggers, and personal websites but I have yet to see one for researchers and PhD candidates. Introducing Spark.

Spark has been developed for researchers and PhD students by a researcher, it is fully SEO integrated. It has the following features:

Running Java 8 With Java 9 and 10 on Windows 10

Wed, 04 Apr 2018 14:33:10 +1200

Oracle has decided that from Java 9 there will be a new java version every six months and the third release would be an LTS release (?). More on it here.

Not all libraries have upgraded them self to the latest Java releases, for example at the time of writing this Scala 2.12.5 doesn’t fully support Java 9, so I still had to use Java 8. For some reason, if you want to experiment with the newer releases of Java and for the same reason, if you install Java 9 or 10, you just cannot run Scala (or other libraries that run Java 8) that’s because Java 9/10 changes your path. Even though you add a JAVA_HOME variable, you still find Java 9/10 being used in command line.

Export Your Github and Gitlab Releases as a Changelog

Mon, 22 Jan 2018 13:02:05 +1200

The repository can be found at https://github.com/akshaybabloo/release-exporter-old.

At the time of writing this blog post, I have 55 repositories on my GitHub account, and more than half of them are active. None of the repositories has a changelog in it, but I have made sure that I have written the release notes at the time of releasing the package/software.

So why do we need changelog you ask? I would recommend reading this and this.

Using Dirent With Msvc Compilers

Tue, 12 Dec 2017 12:58:56 +1200

At the time of writing this blog, I am developing a C++ version of my Spiks library - libSpikes. I was compiling the libSpikes using Cygwin and MinGW.

If you have used Linux before you can recognise the way Cygwin folder is structured. Cygwin tends to create a complete POSIX environment on the Windows, that means it brings loads of DLL files to compile C++ files. MinGW, on the other hand, brings the functionality of Win 32 API’s and also provides specific POSIX API’s.

Collatz Conjecture Lets Compute This

Thu, 17 Aug 2017 12:51:48 +1200

Before we look into what a Collatz conjecture is, I highly recommend watching the (below video by Numberphile.

Collatz conjecture also called as $3n+1$ problem, $3x+1$ mapping, Hasse’s algorithm, Kakutani’s problem, Syracuse algorithm, Syracuse problem, Thwaites conjecture, and Ulam’s problem.

Basically, the problem states that all positive whole numbers should eventually compute to $1$, which is based on the following condition:

Part 1.2 Car Nd Masking and Colouring a Region of the Image

Tue, 09 May 2017 12:55:25 +1200

In this part of Car-ND, we will look at how to mask and colour the region.

Table of Contents

1 Basic Math
- 1.1 One Degree Polynomial
2 Let’s Code
- 2.1 Complete Code
- 2.2 Output
3. What’s Next?

1 Basic Math

Before I show you the code, let’s understand some (very) basic mathematics that are necessary to understand for this part

1.1 One Degree Polynomial

A polynomial equation looks something like this (lets call it equation 1):

Part 1.1 Car Nd Detect Road Lanes Using Computer Vision and Python 3

Fri, 24 Feb 2017 11:46:09 +1200

This blog is few part series in the field of Computer Vision and Deep Learning. In this blog, we will try to understand the following questions:

What is Computer Vision?
Why use Computer Vision?
What are the languages out there that do Computer Vision?
A simple example of image manipulation.

1. What is Computer Vision?

According to Wikipedia

Computer vision is an interdisciplinary field that deals with how computers can be made to gain high-level understanding from digital images or videos. From the perspective of engineering, it seeks to automate tasks that the human visual system can do.

Retrieving Dns Records Using Python

Fri, 16 Sep 2016 11:34:26 +1200

You can retrieve DNS records using dnspython package. You can install the package using pip install dnspython.

Gist can be found at https://gist.github.com/akshaybabloo/2a1df455e7643926739e934e910cbf2e

The problem with this package is that you cannot retrieve all the records at a time so a quick and dirty alternative is to put them in for loop. Few record names in this list (ids) raise an exception, for example ANY, this is because there is no DNS record called ANY.

Introduction to Unreal Engine 4

Fri, 16 Sep 2016 11:25:50 +1200

The project files can be downloaded from https://github.com/akshaybabloo/UnrealEngine_4_Notes

UnrealEngine 4 using Blueprint visual scripting system.

Note 1: This project is developed on Mac OSX 10.11.2 using UnrealEngine 4.10.2. It should work on Windows as well.

Note 2: Notes shown below may contain few lines from the original UnrealEngine Documentation.

Outcome

Note 3: This is only a gif file compressed to load easily. The quality of the environment is 1000000% better than this.

Unreal Engine 4 and Samsung Gear VR

Mon, 05 Sep 2016 11:20:47 +1200

A simple game using Unreal Engine 4.10.* and 4.11.2 for GearVR

The code can be found at - https://github.com/akshaybabloo/GearVR-UnrealEngine4

Note 1: For Mac users make sure you download Java 6 -> https://support.apple.com/kb/dl1572 and Java 7. The setup is the same for UnrealEngine 4.11.

Table of content

1 Introduction
2 Requirements
3 Instillation
4 Developing a game
5 Packing it up for Android
- 5.1 Package Configuration
- 5.2 Packing
6 Installing it on Android

License

Setting up WiFi EAP-PEAP on Linux

Sat, 25 Jun 2016 18:29:02 +1200

A few months ago I was trying to setup up WiFi on my Raspberry Pi. That time I didn’t know that Pi has problems with Enterprise WiFi and my university did not provide support to Linux distribution. Thanks to Google I fond the answer.

I don’t want others to have the same problem. Follow these steps to setup up your office/university WiFi.

Step 1: Requirements

Make sure you have your username, password, proxy IP and WiFi SSID. For the sake of this tutorial let’s consider a username, password, proxy IP and WiFi SSID.

Emotiv and Matlab

Mon, 06 Jun 2016 16:29:14 +1200

The code can be found at https://github.com/akshaybabloo/Emotiv-Matlab

Note 1: Please note that this only works on 32-bit version of Matlab

There are two ways to get the data from your Emotiv EPOC device

One -> Copyright (c) May 2010 The Johns Hopkins University Applied Physics Laboratory (JHU/APL).

Table of Contents

1 Structure
2 Requirements
3 Installing mex compiler
4 Using .m files
- 4.1 Using one (EEG Logger)
- 4.2 Using two (Emotiv EEG)
5 Troubleshooting

License

Retrieving User Repositories Using Github Api With Little Help of Python 3

Tue, 02 Feb 2016 11:20:32 +1200

There are different ways to retrieve user repositories; one such is using Python libraries, but they usually need your API keys even though your repository is public. We could do this by using GitHub’s API v3 HTTP request.

For example, to retrieve my public libraries I would use https://api.github.com/users/akshaybabloo/repos, this returns a JSON array; we just have to use the Python’s json standard library to get the desired key-value pairs (in Python’s terminology - Dictionary).

Blog on Akshay Raj Gollahalli

Tauri 2 With Flutter: A Template

Setting Swapfile on Ubuntu

Running OpenCV with CMake and Ninja

Using QAbstractListModel With QML ListView in Qt6

Importing Existing Project to STM32CubeIDE

Build OpenCV With Visual Studio and CMake CLI

Helpful Powershell Cmdlets/Functions

List all USB devices

Get the size of a folder

Build OpenCV With Visual Studio and CMake GUI

git-alias: Over Engineered Pretty Git Alias Printer

dnode: Search and Delete Node Modules Folders Recursively

uHugo: A CLI Tool for Hugo Static Site Generator

Cookiecutter Template for Writing Go Command Line Interface

Requirements

Usage

Setting Azure AD B2C Authentication in Postman

Creating Custom Widget for QListWidget in Qt 6

Mongo: A MongoDB Helper for Go Language

Stopping HTTP Server Gracefully: Context vs Channels vs SyncGroup

dotnetcore: A .Net Core SDK Uninstaller for POSIX (now with Windows support)

Instillation

Usage

Using SLF4J With Apache Log4j: An Example

1. Requirements

azsecrets: A CLI to Set Azure Key Vault as Environment Variables

Splitting Django Settings for Local and Production Development

.dockerignore file

Setting Up Powershell Core in Visual Studio Code for macOS

1. Installing Homebrew

2. Installing Visual Studio Code

Spark: A Hugo Theme for Researchers

Running Java 8 With Java 9 and 10 on Windows 10

Export Your Github and Gitlab Releases as a Changelog

Using Dirent With Msvc Compilers

Collatz Conjecture Lets Compute This

Part 1.2 Car Nd Masking and Colouring a Region of the Image

1 Basic Math

1.1 One Degree Polynomial

Part 1.1 Car Nd Detect Road Lanes Using Computer Vision and Python 3

1. What is Computer Vision?

Retrieving Dns Records Using Python

Introduction to Unreal Engine 4

Unreal Engine 4 and Samsung Gear VR

Setting up WiFi EAP-PEAP on Linux

Step 1: Requirements

Emotiv and Matlab

Retrieving User Repositories Using Github Api With Little Help of Python 3

`.dockerignore` file