Spring boot + WebFlux (Kotlin) + reactive mongodb and r2dbc (H2) codebase containing real world examples (CRUD, auth, advanced patterns, etc) that adheres to the RealWorld spec and API.

This codebase was created to demonstrate a backend of a fully fledged fullstack application built with **Spring boot + WebFlux (Kotlin) ** including CRUD operations, authentication, and etc.

This codebase intentionally uses an "unusual" setup of the persistence tier with both reactive mongodb, and r2dbc over H2 for reactive relational database. This setup demonstrates that spring webflux can work well with both reactive nosql datastore, such as mongodb, cassandra, gcp firestore and etc., and "traditional" relational database, such as h2, mySql, oracle, with the help of r2dbc (reactive to database connector). And these two datastore technologies works "peacefully" side by side in a single project module. 😁

An application of such setup can have a delayed decision on the kind of the datastore solution for the project. The data service layer makes the transition to either direction "relatively" painless.

We've gone to great lengths to adhere to the **Spring boot + WebFlux (Kotlin) ** community style guides & best practices.

For more information on how to this works with other frontends/backends, head over to the RealWorld repo.

How it works

It uses Kotlin 1.7.20, and Spring Reactive Stack: WebFlux + Spring Data Reactive MongoDB + Spring Data R2DBC (H2).
It provides ability to handle concurrency with a small number of threads and scale with fewer hardware resources, with functional development approach.

• WebFlux spring boot 2.7.2
• MongoDB Reactive
  • (embedded) mongodb: 3.5.5 (see application.yml)
• r2dbc-h2 0.9.1
  • h2: 2.1.210 (see build.gradle.kt)

Database

It uses embedded MongoDB database, and r2dbc-h2 database for demonstration purposes.

Basic approach

The quality & architecture of this Conduit implementation reflect something similar to an early stage startup's MVP: functionally complete & stable, but not unnecessarily over-engineered.

Project structure

- api - the controllers
- dto - non-persistence tier data structures
- persistence - includes entities, repositories and support classes
- exceptions - exceptions and exception handlers.
- security - security settings.
- service - contains the business logics (note: spock unit tests).
- validation - custom validators and validation settings.

Tests

1. Integration tests covers followings,

• End to End api tests using test harness covers all the happy paths.
• Repository test on customized repository impl
• Security

2. Unit tests utilize spock framework to mock the scenarios that not easily repeatable by Integration test

• api handlers
• services

Getting started

You need JAVA 17 installed.

• to build ./gradlew clean build
• to run ./gradlew booRun
  • run in debug mode ./gradlew bootRun --debug-JVM, and attach the debugger to the spring boot process

To test that it works, open a browser tab at http://localhost:8080/api/tags .
Alternatively, you can run

curl http://localhost:8080/api/tags

Run test

The repository contains a lot of test cases to cover both api test and repository test.

./gradlew test

Help

Please fork and PR to improve the project.

Credits

Thanks to project Spring Boot + WebFlux + MongoDB from which this project adopted its code bases of the integration tests.