The Open Closed Principle

In this post, I continue to share what I have learned about the SOLID principles in the book “Clean Architecture A Craftsman’s Guide to Software Structure and Design”. As a recap, six principles make up the SOLID acronym:

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

In the previous post, I wrote about the Single Responsibility Principle. In this post, I write about the Open Closed Principle.

The Single Responsibility Principle

Recently, I read the book “Clean Architecture” by Robert C. Martin. Overall, this is a great book with a wealth of information on software design principles to guide developers to build scalable, maintainable and flexible applications. A core part of the book discusses about six design principles which together make up the acronym SOLID.

Differences between a Promise and an Observable

In this post, I outline a few fundamental concepts I have learned about an Observable and how it is different than a Promise.

Before discussing the differences between an Observable and a Promise, let’s talk about what they have in common. Both Observables and Promises are frameworks for producing and consuming data. They follow the push protocol which means the producer determines exactly when to send the data to the consumer. In comparison, in a pull protocol, the producer only produces data when the consumer asks for it.

Caching node modules and Cypress installation in an azure devops pipeline.

I have a back-end-for-front-end application which I scaffolded using Visual Studio. The backend is an ASP.NET core web API, and the front end is Angular. In the angular application, I have Cypress end-to-end tests that I want to run as part of a build pipeline. Accomplishing the objective requires a few things. For instance, I need to install Cypress binaries on the build agent. I also need to start the angular app to which the tests can run again. Installing Cypress binaries is a lengthy process, and with other steps, the entire build can take a long time to finish. After a few trial and error, I finally got the build to run Cypress tests and cache the binaries. Keep in mind that caching makes sense if the time it takes to save and restore the cache data is considerably less than the time it takes to download and install the data directly.

Using Azure AD Entitlement Management to onboard and manage users.

In the previous post, I talked about using self-service sign-up via user flows to onboard an external user. With self-service sign-up, you can integrate with custom REST endpoints to implement approval workflows and other business logic. I’ve learned of another way to onboard and manage a user’s access by using Entitlement Management, which has built-in rich approval workflow and access lifecycle so you don’t have to build additional APIs to implement an approval workflow.

Getting started with Azure AD Self-Service Sign-Up via user flows

Microsoft has added several great features to help with managing identity and access of an external user in B2B collaboration. One such feature is the Azure AD Self-Service Sign-Up via user flows for an external user to sign up as a guest user in the host Azure AD tenant. I found the feature to be promising, but at the time of writing, it’s still in preview and have limitations.

Dynamically adjust font size of text to fit into a PDF text field using iTextSharp.LGPLv2.Core.

In one of the asp.net core projects I worked on, I used iTextSharp.LGPLv2.Core to programmatically fill out a PDF form. Sometimes, we have a string that is too long to fit within the rectangle area of the text field. After a bit of googling, I found and adopted the solution in this StackOverFlow to solve this problem by dynamically compute the appropriate font size I can use so that the value can fit within the field.

Repository pattern

The repository pattern is a common pattern for accessing data from a database and converting the data into an entity. The repository pattern is property the one I have used the most. But just recently, I started reading more on the different design patterns and realized a few things I did not know or misunderstood about the pattern.

Multi-layer / Multi-tier architectural pattern

In the past, I had been working on applications that were multi-layered / multi-tier applications. However, I had not recognized the terminologies as well as the subtle differences between multi-layered and multi-tier architectures and some of the pitfalls one may want to watch out for when implementing the pattern.

Integrate Azure AD B2C reset password user flow in angular using oidc-client-js.

This post continues from previous posts which I go over using oidc-client-js to interact with azure adb2c:

• Integrate a sign up / sign in user flow to authenticate a user against azure adb2c
• Integrate a edit-profile user flow.

In this post, I’m going to share how to handle resetting password.

You can find the sample project here.