Reactive RESTFul API - MongoDB

NoSQL databases represent a new challenge when compared to relational databases. Combined with Reactive Programming Paradigm implemented by Spring Webflux fully supporting Reactive Streams is a game changer on how to take advantage of using asynchronous stream processing with non-blocking back pressure, dealing with a document-based database, offering significant gains of performance for those applications that must support thousands of simultaneous requests.

Table of contents

• Overview
• Requirements
• Project Structure
• Howto Build and Run
• Screenshot
• Links
• Built with
• Code Snippet
• Continued development
• Useful resources
• Author
• Portfolio

Overview

This API offers reactive endpoints to return Posts and Comments associated to a User according to this the JSON schema:

{
    _id: ObjectId('67b0edf01a432d53fce1d509'),
    moment: ISODate('2025-02-13T14:50:00.000Z'),
    title: 'Business Trip',
    body: 'Travel to Sampa',
    author: {
        name: 'Maria Brown'
    },
    comments: [
        {
            text: 'Have a nice and safe trip',
            moment: ISODate('2025-02-13T14:55:00.000Z'),
            author: {
                name: 'Alex Green'
            }
    },
        {
            text: 'Enjoy it!',
            moment: ISODate('2025-02-13T14:59:00.000Z'),
            author: {
                name: 'Bob Grey'
            }
        }
    ],
    _class: 'br.dev.ferreiras.mongodb.models.entities.Post'
}

Features

The API has been coded using Java 21, Spring Boot 3.4.2, MongoDB 4.4.2, Maven, Javadoc, Reactive Spring MongoDB, Spring Webflux and Docker.

Project Structure

• docs
  • javadocs
• src
  • main
  • java
    • br.dev.ferreiras.mongodb
      • config
      • controller
        • handlers
      • dto
      • model
        • entities
        • dto
        • embedded
      • mapper
      • repository
      • services
        • exceptions
  • resources
    • application-test.properties
    • application-properties
  • test

Howto Build and Run

- MongoDB Database : http://127.0.0.1:27017
- profile active: test
- service socket: 127.0.0.1:8080
- tweak a few knobs to get it up and running

Screenshot

Links

• Live Site URL: API MongoDB

Built with

Code Snippet

/**
 *
 * @author ricardo@ferreiras.dev.br
 * @version 1.1.030901
 * @since 1.0
 *
 */
@Repository
public interface PostRepository extends ReactiveMongoRepository<Post, String> {


  @Query("""   
      {
      'title': { $regex: ?0, $options: 'i' }
      }
      """)
  Flux<Post> searchByTitle(String text);

  @Query(
      """
          {
            $and: [
              { 'moment': { $gte: ?1 } }, { 'moment': { $lte: ?2 } }, {
                $or: [
                  {'title': { $regex: ?0, $options: 'i' } },
                  {'body':  { $regex: ?0, $options: 'i' } },
                  {'comments.text': { $regex: ?0, $options: 'i' } }
                ]
              }
            ]
          }
          """)
  Flux<Post> fullSearch(String text, Instant startMoment, Instant endMoment);

  Flux<Post> findByTitleContainingIgnoreCase(String text);
}

Continued development

• Unit Tests
• HATEOAS
• Versioning
• Swagger Docs

Useful resources

• [https://spring.io/] Awesome Java framework!.
• [https://start.spring.io/] Handy startup tool.
• [https://mvnrepository.com/] Tools that help tackle the beast
• [https://docs.spring.io/spring-data/mongodb/reference/] MongoDB reference doc
• [https://www.reactive-streams.org/] Reactive Streams
• [https://docs.spring.io/spring-framework/reference/web/webflux.html/] Spring Webflux

Author

Ricardo Ferreira

- Portfolio

My Portfolio...