Configure the use of custom ObjectMapper for GraphQL

[Nxtra]

How can I specify an ObjectMapper that has to be used when calling the /graphql endpoint?

I found this issue: #97. Where a combination of ObjectMapperConfigurer and schemaParserOptions is mentioned.

I currently have the following JacksonConfig.

@Configuration
public class JacksonConfig {

    @Bean
    public ObjectMapper objectMapper() {
        return new ObjectMapper()
                .setDefaultPropertyInclusion(JsonInclude.Include.NON_EMPTY)
                .findAndRegisterModules();
    }

    @Bean
    ObjectMapperConfigurer objectMapperConfigurer() {
        return (mapper, context) -> mapper.setDefaultPropertyInclusion(JsonInclude.Include.NON_NULL);
    }

    @Bean
    SchemaParserOptions schemaParserOptions() {
        return SchemaParserOptions.newOptions()
            .objectMapperConfigurer((ObjectMapper mapper, ObjectMapperConfigurerContext context) -> mapper.setDefaultPropertyInclusion(JsonInclude.Include.NON_NULL))
            .build();
    }
}

As you can see I am trying to set a different setting for DefaultPropertyInclusion when calling the \graphql endpoint.
(This is because I want the empty interfaces: [] array to be in the response from the introspection)

However, currently with the above configuration, the ObjectMapper with DefaultPropertyInclusion = NON_EMPTY is still being used when doing the graphql introspection. Instead of the ObjectMapper with DefaultPropertyInclusion = NON_NULL.

Can you help me with how I should configure a custom ObjectMapper for the queries on /graphql?

[neerajsu]

@Nxtra What is the need to set objectMapper in 3 different beans. Just SchemaparserOptions should suffice. Have you tried removing the other beans and checking if its working?

[Eboubaker]

I had problems with ObjectMapper trying to serialize ApplicationPart (uploaded file). This is how I did it ( I intercept the _convert call of ObjectMapper)

import com.coxautodev.graphql.tools.SchemaParserOptions;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import graphql.schema.*;
import graphql.servlet.core.ApolloScalars;
import graphql.servlet.core.DefaultObjectMapperConfigurer;
import org.apache.catalina.core.ApplicationPart;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class GraphQLConfig {
    @Bean
    public GraphQLScalarType uploadScalar() {
        return ApolloScalars.Upload;
    }

    @Bean
    public SchemaParserOptions schemaParserOptions() {
        var defaultObjectMapperConfigurer = new DefaultObjectMapperConfigurer();
        return SchemaParserOptions.newOptions()
            .objectMapperProvider(fieldDefinition -> {
                var mapper = new ObjectMapper() {
                    @Override
                    protected Object _convert(Object fromValue, JavaType toValueType) throws IllegalArgumentException {
                        if (toValueType.getRawClass().equals(ApplicationPart.class)) {
                            return fromValue;
                        }
                        if (toValueType.hasContentType()
                            && toValueType.getContentType().getRawClass().equals(ApplicationPart.class)) {
                            return fromValue;
                        }
                        return super._convert(fromValue, toValueType);
                    }
                };
                defaultObjectMapperConfigurer.configure(mapper);
                return mapper;
            })
            .build();
    }
}

This is what I have in the graphql Mutation

scalar Upload
type Mutation {
    saveOrder(attachments: [Upload!]!, order: OrderInput!): Order
}

In the service:

import com.coxautodev.graphql.tools.GraphQLMutationResolver;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
@Service
public class OrderService implements GraphQLMutationResolver {
    @Transactional
    public Order saveOrder(List<ApplicationPart> attachments, @NotNull Order order) {
        // 
    }
}

my build.gradle:

dependencies {
    implementation("com.graphql-java-kickstart:graphql-spring-boot-starter:5.10.0")
}