Chain of responsibility is a behavioural design pattern that allows a response to be passed along a chain of handlers. Each handler receives the request in sequence and optionally acts on it before passing it on to the next handler. This design pattern is useful to cases where processing of a request is done in a sequence of steps. By using handler for each of the step, the code can be loosely coupled with the main program and easy to maintain in the future.

One example of using this design pattern is dealing with an interactive Q&A where question is…

The goal of unit testing is to segregate each part of the program and test if that individual part is working correctly. This is the practise that improves the quality of code, enables bugs to be found at early stages, and facilitates any future changes and refactorings. This article talks about the steps on transforming a custom Sitefinity widget to be unit testable and how to perform it.

Starting point

Sitefinity is a CMS that allows developers to use ASP.NET MVC to build custom widgets. …

xUnit is a unit testing framework which supports .NET Core . I use it to unit test my Document Controller WPF application (.NET Framework 4.6.1) and in this project, the AutoMapper is heavily used to map domain models to view models.

I wrote unit tests for each class and when the unit tests were run, I got the following error:

System.InvalidOperationException: 'Mapper already initialized. You must call Initialize once per application domain/process.'

This error is due to the design of xUnit (Version 2.4.0) and AutoMapper (Version 7.0.1). xUnit groups tests (methods that have the attributes fact or theory) by their…

This is the first minimal viable product that has been published and used by the company.

The first version of the Document Controller is a WPF application which can be installed and launched in any Microsoft Windows Operating Systems with .NET Framework 4.6.1 installed. This application works hand in hand with a database in Microsoft Access format which is available in the company local network drive. It was completed on 23 November 2018 with the git tag v-1.0.0 being used to label the corresponding git commit in the source code repository.

Among the several core features of this application are:

Feature 1: Searching for Documents

…

I fell in love with programming when I first learnt C during the first year of my undergraduate study. Little did I know that was the beginning of my lifelong relationship with it (ok, I admit it was not really that long 😅). After I had the first contact with C, I started to learn C# and immediately noticed the beauty of this high-level object-oriented programming language. I made use of it in my internship to develop an application to automate performance test analysis. …

Document control system has always been important to any company and organisation to ensure the existence of controlled process and practices for the creation, review, modification, issuance, distribution, and accessibility of documents. Unfortunately, as someone who is tasked to take on this role, I have noticed that the document control system in my company has been inefficient and ineffective:

• Hard-copy form is used to record all requests made to revise documents. Data entry to the document control master list in spreadsheet is needed. These forms need to be filed in file folders for record keeping.
• All of the document revisions…

Web API often needs to be protected from malicious users. This article aims to show how simple authentication and authorisation can be implemented in a sample ASP.NET Core Web API app (“sample app”).

I have used the following tools to build the sample app:

• Visual Studio Code (my favourite code editor)
• SQL Server (it was run inside a Docker container because the sample app was built in macOS)
• EntityFramework Core (a good ORM that came with ASP.NET Core)

How the Simple Authentication and Authorisation Works

With authentication and authorisation implemented, my sample ASP.NET Core Web API app only accepts HTTP request with valid JSON web token (JWT)…

Upon completing the server app and having it tested while coding using Postman, I have felt that it has become a good time for me to deploy the project and host it in an actual server machine. Like most developers who are relatively new to server development and ASP.NET Core, I frequent Microsoft documentation site for official instructions on using their technologies.

Basically, the steps involve:

1. Publish your project from Visual Studio;
2. Transfer your published project files into a folder in the server machine;
3. Install IIS in your server machine;
4. Install ASP.NET Core hosting bundle for Windows (with correct version);
5. …