Backport GenericJackson2JsonRedisSerializer.configure(…) to 3.1.x

[roeniss]

GenericJackson2JsonRedisSerializer(ObjectMapper mapper) constructor removes the chance to apply setup in GenericJackson2JsonRedisSerializer(@Nullable String classPropertyTypeName).

Currently I managed to make copy of GenericJackson2JsonRedisSerializer.TypeResolverBuilder like this:

    @Bean
    GenericJackson2JsonRedisSerializer genericJackson2JsonRedisSerializer(ObjectMapper mapper) {
        GenericJackson2JsonRedisSerializer serializer = new GenericJackson2JsonRedisSerializer(mapper);
        GenericJackson2JsonRedisSerializer.registerNullValueSerializer(mapper, null);

        StdTypeResolverBuilder typer = new TypeResolverBuilder(DefaultTyping.EVERYTHING,
                mapper.getPolymorphicTypeValidator());
        typer = typer.init(JsonTypeInfo.Id.CLASS, null);
        typer = typer.inclusion(JsonTypeInfo.As.PROPERTY);
        
        if (StringUtils.hasText(classPropertyTypeName)) {
	        typer = typer.typeProperty(classPropertyTypeName);
        }
        mapper.setDefaultTyping(typer);

        return serializer;
    }

    private static class TypeResolverBuilder extends ObjectMapper.DefaultTypeResolverBuilder {
        // ... (same implementation with original)
    }

original in the comment means this: https://github.com/spring-projects/spring-data-redis/blob/main/src/main/java/org/springframework/data/redis/serializer/GenericJackson2JsonRedisSerializer.java#L381

I hope there's a more simple way to do this.

[jxblum]

From your code snippet above, it is not apparent what aspects of Jackson's ObjectMapper you customized. I assume you declared an object of type ObjectMapper as a managed bean in the Spring context? The question is, does the ObjectMapper instance really need to be managed by the Spring container?

NOTE: There are other situations where Spring Data Redis's GenericJackson2JsonRedisSerializer creates and maintains separate and internal instances of ObjectMapper. For example.

It is apparent that you are duplicating the logic from this constructor, but are allowing the ObjectMapper to passed during construction, presumably because you constructed a "custom" instance of ObjectMapper as a managed bean in the Spring container.

You can accomplish this another way, if you do not need the ObjectMapper to strictly be a managed bean in the Spring context.

NOTE: For the record, is it questionable whether declaring an ObjectMapper as a managed bean is strictly necessary given customizations are quite use case and/or domain specific.

Simply do the following:

@Configuration
class MyApplicationRedisConfiguration {

    @Bean
    GenericJackson2JsonRedisSerializer jsonRedisSerializer(
            @Value("${spring.redis.serialization.class-property-type-name}") String classPropertyTypeName) {

        GenericJackson2JsonRedisSerializer jsonRedisSerializer = 
            new GenericJackson2JsonRedisSerializer(classPropertyTypeName);

        jsonRedisSerializer.configure(objectMapper -> {
            // add ObjectMapper customizations here
        });

        return jsonRedisSerializer;
    }
}

Additionally, your "jsonRedisSerializer" @Bean method could also be "injected" with other configuration used to customize the ObjectMapper created by Spring Data Redis's GenericJackson2JsonRedisSerializer (as seen here).

I demonstrated such an injection with the classPropertyTypeName configuration. Clearly, you are able to add others.

[roeniss]

configure is the one that I need. Thank you jxblum! I'm using Spring bom 2.7.15 so I didn't notice such method exists (that method is added on 3.1.1 with this PR).

The question is, does the ObjectMapper instance really need to be managed by the Spring container?

I needed not the one in Spring container but one with jsr310 module added. When I debugged, objectmapper that is newly made in GenericJackson2JsonRedisSerializer has only one module, and Spring-managed objectmapper has 7 modules including jsr310 (for me, it is needed to serialize/deserialize Instant type). I had to use Spring's one or make one by myself. Either way needs duplicating logic as you might guess.

[jxblum]

Hi @roeniss - Right, I was also wondering the version of the Spring (Boot/Data) BOM you had in play. Thank you for sharing that information. I always base my answers on the latest bits if not otherwise specified.

Anyway, I will talk to the team about potentially back porting this method (configure(:Consumer<ObjectMapper>)).

[roeniss]

Thank you so much! Farewell.

[jxblum]

@mp911de & @christophstrobl - I propose we (minimally) back port the configure(:Consumer<ObjectMapper>) method (source & Javadoc) I added to SD Redis to resolve Issue #2601, to 3.0.x and 2.7.x.

Thoughts?

[mp911de]

As this change (GenericJackson2JsonRedisSerializer.configure(…)) is already part of 3.1.x, closing this issue.