Firebase Realtime Database repositories for Spring Boot

Provides a generic way to interact with the Firebase Realtime Database in a Spring Boot application. It basically provides a generic repository that mimics the main REST endpoints to be used most probably in backend admin applications. Here is the list of methods that have been implemented:

• set
• update
• push
• remove
• removeAll
• get
• find
• findAll

Getting started

Preconditions

• you need to have a RestTemplate bean available
• you need to have Jackson on the classpath

But they usually come easily with web applications using:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

Declare dependencies

To use this, just include these dependencies in your pom:

<dependency>
    <groupId>com.github.fabiomaffioletti</groupId>
    <artifactId>spring-boot-starter-data-firebase</artifactId>
    <version>1.0.0.RELEASE</version>
</dependency>

...and you need also the firebase-admin dependency on your classpath:

<dependency>
    <groupId>com.google.firebase</groupId>
    <artifactId>firebase-admin</artifactId>
    <version>[version]</version>
</dependency>

Configuration

To get it to work you need to:

1. go to your firebase console, generate a service account file and include it in your classpath or in your file system
2. specify two things in your application.properties (or yml) file

firebase.service-account-filename=[classpath|file]:[service-account-filename].json
firebase.realtime-database-url=[realtime database url] # for example https://your-application.firebaseio.com

The code part

Then, on the Java part:

1. create a class representing the document you need to persist
2. annotate it with @FirebaseDocument, specifing the realtime database path
3. create an ID property and annotate it with @FirebaseId

@FirebaseDocument("/albums")
public class Album {

    @FirebaseId
    private String id;

    private String title;

}

Then create a class that extends the DefaultFirebaseRealtimeDatabaseRepository class, and annotate it with @Repository or mark it as a Spring @Bean in your application configuration.

@Repository
public class AlbumRepository extends DefaultFirebaseRealtimeDatabaseRepository<Album, String> {
}

Finally, put @EnableFirebaseRepositories just next to @SpringBootApplication or in any @Configuration class in your application.

Notes

This is at its very early development stages. I did it because I found a lot of code and configuration duplication in every Firebase project I worked on. It is very far from what I would like it to be, but still I wanted to expose it to the community, hoping that it would be improved and used by people with the same needs as mines.

I could not commit the firebase service account file I am using for testing, so if you would like to contribute, you should create the service account file and put it in the src/test/resources/application.properties file.

Next steps

• Provide repositories for Cloud Firestore
• Provide repositories for Cloud Storage
• Automatically register repository beans interfaces rather than annotated classes