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Logic Behind Software — allMatch On Empty Stream

Basically, it works this way because of the logic concept called Vacuous truth. It is a simple and short answer but because we do not like such answers, we will dive deeper. But why I even decided to write about such a niche topic. For some time, I have been interested in how mathematics affects the software engineering world directly, and I have even written an article about calculating scalability. I believe such niche topics can be quite an interesting thing for you.

We will start by shortly presenting the main problem described in today's text.

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Contention, Coherency, and Math Behind Software

Today I want to tell you a few words about how you can describe your system through mathematical equations — at least to some degree. You will get familiar with terms like Contention, Coherency, and Coherency Delay. Additionally, I want to show you laws and their mathematical equations that can help you calculate the impact of these 3 mechanics on your application.

This article is more focused on overall system design and architecture than any other written by me till today — so consider yourself warned. In the article, I will try to answer a question: Can we scale systems indefinitely? 

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Dive Into OAuth Grant Types and OpenID Connect Flows

In my last article, you could read about the differences between OAuth, SAML, and OpenID Connect. Today I want to continue the topic. We will dive deeper into the processes of authentication and authorization offered to us by respectively (OpenID Connect) and (OAuth). However, we will start with a few words about the naming conventions in both.

GrantTypes vs Flows — Semantic Difference

In general, both terms are correct and can be used simultaneously. Both of them describe the same thing – a process of obtaining an Access Token. Just keep in mind that the term “Grant Type” is more strongly related to OAuth, while the term “Flow” is more related to OpenID Connect. As a side note, I can add that the term “Flow” rarely occurs in the OAuth specification.

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Sending SMS With Scala

As you probably guessed from the title above, sending an SMS is the main topic of today's article. I started the articles with a few words about SMS service providers, then I explained what you may take into consideration while choosing the one for you, why I choose the Vonage, and added some more details about this platform. I also provided a simple step-by-step implementation of SMS sender service in Scala. 

Before we start — a quick disclaimer
 Here you can find only the most interesting code samples. The full source code is available in my GitHub repository. The link is provided in the end of the article. 


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Secure Spring Boot Application With Keycloak

In my last article about Keycloak, I mentioned the Spring Boot as one of the frameworks to integrate with Keycloak. Here I will dive deeper into how to integrate them, namely, I will describe how you can secure your Spring Boot-based REST API with help of Keycloak. I will also add a few words about the Keycloak admin console and how to use it. Of course, all necessary configurations from Spring Boot’s side will also be detailed and explained. 

Before we start — a quick disclaimer

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What Is Keycloak and What Does It Offer?

Application security is becoming a more and more important topic on a day-to-day basis. Unauthorized access to protected data can potentially cost millions of dollars in the form of various financial penalties. Almost every application needs some reliable tool to manage its users’ identities and accesses. There are a bunch of solutions on the market — both free and paid — that promise to provide such features. In today’s article, I will try to present you one of these tools, which as you probably guess from the title, will be Keycloak. I hope that this article will give you a better understating of its basics and why it may be profitable for you to get more familiar with it. As usual, I will start with a short description of what Keycloak exactly is.

Before we start — a quick disclaimer

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Database Migration tools: Flyway vs. Liquibase

I believe that there is no need for describing why the usage of database migration tools is vital for modern days apps that utilize relational database engines. I will only say that they can make our life much easier and help us to automatize a complex and repetitive process.

Through the course of this article, I will provide some more insights into similarities and differences between two of the most common open-source migration tools, namely Flyway and Liquibase.