Build and deploy a WebJob alongside web app using azure pipelines

In this post, I’m going to share some of the issues, misunderstandings I ran into when trying to setup and deploy a WebJob alongside a web application using azure pipelines. The WebJob is a console application, and the web app is an ASP.NET core. Both the WebJob and web app target .NET 5.

More on inheritance

Inheritance is something that comes up quite often during my programming experience. Whenever I have classes that share some logic or properties, I think of inheritance. However, sometimes, using inheritance ends up making a design more brittle. Through my experience and reading, I have learned a few things about inheritance.

Authenticate against azure ad using certificate in a client credentials flow

I have an API which needs to authenticate against azure ad to obtain an access token for calling another downstream API. When registering an application in azure AD for the caller API, I could either setup a shared secret or a certificate for the API to use as part of its credentials in a client credentials flow . In the past, I had always used a shared secret as it was more convenient and easier to setup. However, using certificate provides stronger security. After spending a few hours of googling and hacking, I was able to setup and use a certificate instead of a shared secret as credentials for the caller API to authenticate against azure AD.

Template method example

In a project I work on, I need to programmatically fill out some PDF forms. The forms are very similar in terms of structure, content, and fields’ names. Using iTextSharp library, I can go through the fields in the PDF and set the values. The logic for filling out a PDF form can be generic, as I just need to know what are the fields’ names and the corresponding values of the PDF. I come up with a generic model and common logic for filing out the form, as demonstrated in the below snippets.

Notes on The Clean Architecture

In this post, I’m going to share my understanding of clean architecture after reading about it in the book “Clean Architecture” and other posts, as well as how I implement the clean architecture in an ASP.NET core project.

Notes on The Dependency Inversion Principle

The Dependency Inversion Principle is the last principle in SOLID. As a recap, SOLID is an acronym that stands for the five software design principles which Robert Martin discusses in his book “Clean Architecture – A Craftsman’s Guide to Software Structure and Design”.

• S: Single Responsibility Principle
• O: Open Closed Principle
• L: Liskov Substitution Principle
• I: Interface Segregation Principle
• D: Dependency Inversion Principle

Migrating from Microsoft.AspNetCore.Authentication.AzureAD to Microsoft Identity Web authentication library to integrate with Azure AD.

I recently had a chance to clean up some of the deprecated libraries I used for validating a JWT access token or obtain one via the client-credentials flow or the on-behalf-of flow. The libraries I used were under the Microsoft.AspNetCore.Authentication.AzureAD packages. Per the document, since ASP.NET core 5.0, users should use the Microsoft.Identity.Web package to integrate with Azure AD and Azure ADB2C.

Notes on the Interface Segregation Pattern

The Interface Segregation Pattern (ISP) is one of the principle in SOLID. As a recap, SOLID is an acronym which stands for the five software design principles:

• The Single Responsibility Principle
• The Open Closed Principle
• The Liskov Substitution Principle
• The Interface Segregation Principle
• The Dependency Inversion Principle

Rendering a PDF in angular that works with mobile browsers using ng2-pdf-viewer

In several applications I worked on, we used iframe to display PDFs. The PDF displays fine on desktop browsers. However, on a mobile browser such as Safari on iPhone and iPAD, only the first page shows up. Many people have run into the same issue, as discussed in this stackoverflow post and also on the apple communities page.

Three essential libraries for unit testing a .NET project

In this post, I share the three libraries I find useful for unit testing a .NET project: EF Core SQLite Database Provider, Bogus and Moq.