Spring Boot GraphQL Aliases Fields

A GrahphQL server returns a Query Operation result, that may contain a variable that later needs to be renamed as per client requirement.GraphQL supports Field Aliases that support the renaming of variable at Query time only.

package org.wesome.graphql.controllers;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.graphql.data.method.annotation.Argument;
import org.springframework.graphql.data.method.annotation.QueryMapping;
import org.springframework.stereotype.Controller;
import org.wesome.graphql.entity.Apple;
import org.wesome.graphql.service.AppleService;

import java.util.List;

@Controller
public class AppleGraphQLController {
    @Autowired
    private AppleService appleService;

    @QueryMapping("findAppleByTaste")
    List<Apple> findAppleById(@Argument String appleTaste) {
        return appleService.findAppleByTaste(appleTaste);
    }

    @QueryMapping("findAllApple")
    List<Apple> findAllApple() {
        return appleService.findAllApple();
    }
}

package org.wesome.graphql.entity;

public record Apple(int appleId, String appleName, String appleTaste) {
}

package org.wesome.graphql.entity;

public enum AppleTaste {
    SWEET("sweet"), TANGY("tangy"), BITTER("bitter"), SOUR("sour");
    private final String appleTaste;

    AppleTaste(String appleTaste) {
        this.appleTaste = appleTaste;
    }
}

package org.wesome.graphql.service;

import org.wesome.graphql.entity.Apple;

import java.util.List;

public interface AppleService {
    List<Apple> findAppleByTaste(String appleTaste);

    List<Apple> findAllApple();
}

package org.wesome.graphql.service;

import com.github.javafaker.Faker;
import org.springframework.stereotype.Service;
import org.wesome.graphql.entity.Apple;
import org.wesome.graphql.entity.AppleTaste;

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

@Service
public class AppleServiceImpl implements AppleService {
    private static List<Apple> apples;

    static {
        Faker faker = new Faker();
        apples = IntStream.rangeClosed(1, 10).mapToObj(value -> new Apple(value, faker.food().fruit(), AppleTaste.values()[faker.random().nextInt(0, 3)].name())).collect(Collectors.toList());
    }

    @Override
    public List<Apple> findAppleByTaste(String appleTaste) {
        return apples.stream().filter(apple -> apple.appleTaste().equalsIgnoreCase(appleTaste)).collect(Collectors.toList());
    }

    @Override
    public List<Apple> findAllApple() {
        return apples;
    }
}

package org.wesome.graphql;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class GraphqlProjectApplication {
    public static void main(String[] args) {
        SpringApplication.run(GraphqlProjectApplication.class, args);
    }
}

\src\main\resources\graphql\schema.graphqls

# Apple Enumeration
enum AppleTaste {
    SWEET, TANGY, BITTER, SOUR
}
# Apple Object
type Apple{
    # primary key of apple
    appleId:ID!
    # apple Name
    appleName:String
    # apple AppleTaste
    appleTaste:AppleTaste
}
# Apple Query
type Query{
    # query to get all apples
    findAllApple:[Apple]
    # query to get apple by taste
    findAppleByTaste(appleTaste:AppleTaste):[Apple]
}

\src\main\resources\application.properties

spring.graphql.graphiql.enabled=true

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.1.5</version>
        <relativePath/>
    </parent>
    <groupId>org.wesome</groupId>
    <artifactId>spring-boot-graphql</artifactId>
    <version>0.0.1-snapshot</version>
    <name>spring-boot-graphql</name>
    <description>implementing graphql in spring boot</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-graphql</artifactId>
        <dependency>
            <groupId>com.graphql-java</groupId>
            <artifactId>graphql-java-extended-scalars</artifactId>
            <version>21.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webflux</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.graphql</groupId>
            <artifactId>spring-graphql-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

GraphiQL

GraphQL provides an inbuild UserInterface GraphiQL, which can be accessed via http://localhost:8080/graphiql or access GraphQL via Postman, in the query section add the below query

query FindAllApple {
    findAllApple {
        appleId
        appleName
        appleTaste
    }
}

Query Operation with alias

query FindAllApple {
    findAllApple {
        id: appleId
        name: appleName
        taste: appleTaste
    }
}