I am writing this post, because I would like to share some exciting news with you- the Codersee course platform has been fully migrated to codersee.com ? What does it look like? What if I already joined a course purchased through the Teachable platform? What is coming next? Let’s figure out answers to those questions […] The post Codersee Course Platform is Ready appeared first on Codersee - Kotlin on the backend ..read more

The last article in a series dedicated to Spring Boot AWS S3 integration focused on testing with LocalStack and Testcontainers. The post Test Spring Boot AWS S3 with Localstack and Testcontainers appeared first on Codersee | Kotlin, Ktor, Spring ..read more

The second article in a series dedicated to Spring Boot AWS S3 integration focused on S3Template and Kotlin. The post Spring Boot with Kotlin, AWS S3, and S3Template appeared first on Codersee | Kotlin, Ktor, Spring ..read more

A step-by-step guide on how to implement and configure a Spring Boot application to send metrics to Datadog. The post Sending Spring Boot Metrics to Datadog appeared first on Codersee | Kotlin, Ktor, Spring ..read more

Hi guys! Today we will learn how to do integration testing for Spring WebClient that invokes external REST APIs with WireMock and JUnit 5. As an example, we will implement a simple logic responsible for querying the GitHub API using coroutines. Nevertheless, I am pretty sure you will be able to easily adjust this article to your needs. (of course, if you are here only for the WireMock part, then I recommend skipping to the “WebClient Integration Testing With WireMock” chapter). Lastly, I just wanted to add that you can use this testing approach regardless of whether you are using WebClient, R ..read more

In this article, we are going to tackle Reactive Programming in Kotlin. We will start with what exactly Reactive Programming is, how we could use it to our advantage, and what techniques we can use in Kotlin. I am going to explain everything in simple terms to make this article beginner-friendly (considering you know the basics of Kotlin, of course). In some future articles, we will put that knowledge into action on the example of the Ktor project, emphasizing the Reactive approach. So don’t forget to follow me on LinkedIn to not miss out Reactive Programming If you try to search for what Rea ..read more

This comprehensive guide is about setting up a Ktor client that effortlessly retrieves data from OpenWeatherMap API. I’ll tackle client configuration, API calls, models configuration, and error handling, leaving you with a weather-fetching client ready to be used on any platform. Ktor is a flexible library that provides the ability to create a non-blocking HTTP client, which enables you to perform requests and handle responses. Its functionality could be enhanced with plugins, such as logging, serialization, authentication, and so on. Its core benefit is that it’s a lightweight framework that ..read more

Hello and welcome to my next article, in which I will show you how to test a Micronaut application in Kotlin. To be even more specific- we will work with an application that exposes a REST API and connects to MongoDB. If you would like to learn how to do that step-by-step, then you can check out my other article. (But don’t worry, we will see its code snippets in this tutorial, too). For testing, we’re going to use JUnit 5, MockK, REST Assured, as well as the @MicronautTest and Micronaut Test Resources. Micronaut Project Overview Let’s start everything by checking the project we will test toda ..read more

If you have ever struggled with the “Unexpected error occurred: Can’t find a codec for CodecCacheKey” when testing in Micronaut, then you came to the right place In this short article, I will show you how to fix this issue based on the example project. Trigger The CodecCacheKey in Micronaut Test Before I show you how to fix this issue, let me quickly introduce you to how I trigger the CodecCacheKey issue when writing tests in Micronaut. (If you are interested in the whole project, check this article about Micronaut with MongoDB). So firstly, I created a simple AppUser data class: import io.m ..read more

If you would like to learn how to use the kotlinx.serialization library with Ktor and Kotlin, then you just came to the right place! In this article I will show you how to configure it to work with: Ktor Server Ktor Client WebSockets in Ktor Before we start, I just wanted to note that we are going to use a modified project from the lesson about Ktor with Ktorm and PostgreSQL. So if you don’t know how to setup and use a Ktor server with PostgreSQL you should definitely check it up, because I will skip the basics. Additionally, if you’d like to explore kotlinx.serialization in details, then ch ..read more