Spring GraphQL DGS Netflix

https://github.com/spring-boot-tutorials/spring-graphql-dgs-netflix

In this article we will configure Spring Boot to serve GraphQL endpoints.

Create Initial Code Base

Go to https://start.spring.io/
Add the following dependencies:
- graphql-dgs-spring-graphql-starter
- spring-boot-starter-web
- lombok
Click Generate

Dependencies

Dependencies used in pom.xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>com.netflix.graphql.dgs</groupId>
    <artifactId>graphql-dgs-spring-graphql-starter</artifactId>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

GraphQL Schema Files

Create new file src/main/resources/schema/schema.graphqls:

type Query {
    albums(titleFilter: String): [Album]
}

type Album {
    title: String
    artist: String
    recordNo: Int
}

Model

Let’s create a new POJO src/main/java/com/example/spring_graphql_dgs_netflix/Album.java

@Data
public class Album {

    private final String title;
    private final String artist;
    private final Integer recordNo;

    public Album(String title, String artist, Integer recordNo) {
        this.title = title;
        this.recordNo = recordNo;
        this.artist = artist;
    }
}

Component

Create a stub repository with fake data src/main/java/com/example/spring_graphql_dgs_netflix/AlbumDgsComponent.java:

@DgsComponent
public class AlbumDgsComponent {

    // do not name `albumList` as `album` as that would overload the method `album()` for DGS
    private final List<Album> albumList = Arrays.asList(
            new Album("Rumours", "Fleetwood Mac", 20),
            new Album("What's Going On", "Marvin Gaye", 10),
            new Album("Pet Sounds", "The Beach Boys", 12)
    );

    @DgsQuery
    public List<Album> albums(@InputArgument String titleFilter) {
        if (titleFilter == null) {
            return albumList;
        }
        return albumList.stream()
                .filter(s -> s.getTitle().contains(titleFilter))
                .collect(Collectors.toList());
    }
}

Run & Verify Application

Open terminal at project root and execute the following:

mvn spring-boot:run

Goto: http://localhost:8080/graphiql

Execute the following GraphQL query:

query {
    albums(titleFilter: "o") {
        title
        artist
        recordNo
    }
}