Is there a way to support GenericJackson2JsonRedisSerializer?

[FalconIA]

To free up memory, I try to use GenericJackson2JsonRedisSerializer instead.

@Bean
public RedisTemplate<String, ExpiringSession> sessionRedisTemplate(RedisConnectionFactory connectionFactory) {
    RedisTemplate<String, ExpiringSession> template = new RedisTemplate<>();
    template.setKeySerializer(template.getStringSerializer());
    template.setHashKeySerializer(template.getStringSerializer());
    template.setValueSerializer(template.getStringSerializer());
    template.setHashValueSerializer(new GenericJackson2JsonRedisSerializer());
    template.setConnectionFactory(connectionFactory);
    return template;
}

Then get a exception:

com.fasterxml.jackson.databind.JsonMappingException: Unexpected token (END_OBJECT), expected FIELD_NAME: missing property '@class' that is to contain type id  (for class java.lang.Object)
 at [Source: [B@5b44b124; line: 1, column: 283]
    com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:148)
    com.fasterxml.jackson.databind.DeserializationContext.wrongTokenException(DeserializationContext.java:946)
    com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer._deserializeTypedUsingDefaultImpl(AsPropertyTypeDeserializer.java:149)
    com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer.deserializeTypedFromObject(AsPropertyTypeDeserializer.java:101)
    com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer.deserializeTypedFromAny(AsPropertyTypeDeserializer.java:165)
    com.fasterxml.jackson.databind.deser.std.UntypedObjectDeserializer$Vanilla.deserializeWithType(UntypedObjectDeserializer.java:554)
    com.fasterxml.jackson.databind.deser.impl.TypeWrappedDeserializer.deserialize(TypeWrappedDeserializer.java:42)
    com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3736)
    com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2819)
    org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer.deserialize(GenericJackson2JsonRedisSerializer.java:117)
    org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer.deserialize(GenericJackson2JsonRedisSerializer.java:98)
    org.springframework.data.redis.core.AbstractOperations.deserializeHashValue(AbstractOperations.java:316)
    org.springframework.data.redis.core.AbstractOperations.deserializeHashMap(AbstractOperations.java:277)
    org.springframework.data.redis.core.DefaultHashOperations.entries(DefaultHashOperations.java:227)
    org.springframework.data.redis.core.DefaultBoundHashOperations.entries(DefaultBoundHashOperations.java:101)
    org.springframework.session.data.redis.RedisOperationsSessionRepository.getSession(RedisOperationsSessionRepository.java:233)
    org.springframework.session.data.redis.RedisOperationsSessionRepository.getSession(RedisOperationsSessionRepository.java:220)
    org.springframework.session.data.redis.RedisOperationsSessionRepository.getSession(RedisOperationsSessionRepository.java:141)
    org.springframework.session.web.http.SessionRepositoryFilter$SessionRepositoryRequestWrapper.getSession(SessionRepositoryFilter.java:276)
    org.jasig.cas.client.authentication.AuthenticationFilter.doFilter(AuthenticationFilter.java:103)
    org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:343)
    org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:260)
    org.jasig.cas.client.session.SingleSignOutFilter.doFilter(SingleSignOutFilter.java:76)
    org.springframework.session.web.http.SessionRepositoryFilter.doFilterInternal(SessionRepositoryFilter.java:125)
    org.springframework.session.web.http.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:65)
    org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:343)
    org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:260)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Here is a hash value session example:

{"validFromDate":["java.util.Date",1456392459037],"validUntilDate":null,"attributes":{"@class":"java.util.Collections$EmptyMap"},"principal":{"@class":"org.jasig.cas.client.authentication.AttributePrincipalImpl","name":"cas","attributes":{"@class":"java.util.Collections$EmptyMap"}}}

[rwinch]

Thanks for the report!

I think maybe someone from the Spring Data Redis team might be better qualified to answer this. @christophstrobl Any ideas?

[christophstrobl]

MapSession cannot be mapped by jackson without customizing the ObectMapper. Still GenericJackson2JsonRedisSerializer can use a preconfigured ObjectMapper instance.
Please have a look at the follwoing configuration using a MixIn.

@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "@class")
abstract class MixIn {

    @JsonIgnore
    abstract boolean isExpired();
}

// ...

ObjectMapper mapper = new ObjectMapper()
mapper.setVisibility(
    mapper.getVisibilityChecker()
        .withFieldVisibility(Visibility.ANY)
        .withGetterVisibility(Visibility.NONE)
        .withSetterVisibility(Visibility.NONE)
        .withCreatorVisibility(Visibility.NONE));

mapper.addMixIn(MapSession.class, MixIn.class); // register the MixIn
mapper.enableDefaultTypingAsProperty(DefaultTyping.NON_FINAL, "@class"); // enable default typing

GenericJackson2JsonRedisSerializer serializer = new GenericJackson2JsonRedisSerializer(mapper);

Additional customizations might be required for sepecific session content.

[rwinch]

@christophstrobl Thanks for the very detailed answer!

@FalconIA Can you respond if this answers your question?

[FalconIA]

@christophstrobl Thanks for your answer.
Just know that serialization can be configured using mix-in feature.

I try to customize ObectMapper in my project.
I don't registere MapSession with mix-in.
I just register several min-in class to configure class used in session attributes.

@Bean
public RedisTemplate<String, ExpiringSession> sessionRedisTemplate(RedisConnectionFactory connectionFactory) {
    RedisTemplate<String, ExpiringSession> template = new RedisTemplate<>();
    template.setKeySerializer(template.getStringSerializer());
    template.setHashKeySerializer(template.getStringSerializer());
    template.setValueSerializer(template.getStringSerializer());
    template.setHashValueSerializer(new GenericJackson2JsonRedisSerializer(customObjectMapper()));
    template.setConnectionFactory(connectionFactory);
    return template;
}

private ObjectMapper customObjectMapper() {
    ObjectMapper mapper = new ObjectMapper();
    mapper.setVisibility(
            mapper.getVisibilityChecker()
                    .withFieldVisibility(Visibility.ANY)
                    .withGetterVisibility(Visibility.NONE)
                    .withSetterVisibility(Visibility.NONE)
                    .withCreatorVisibility(Visibility.NONE));
    mapper.addMixIn(AssertionImpl.class, AssertionMixin.class); // register the MixIn
    mapper.addMixIn(AttributePrincipalImpl.class, AttributePrincipalMixin.class); // register the MixIn
    mapper.enableDefaultTypingAsProperty(ObjectMapper.DefaultTyping.NON_FINAL, "@class"); // enable default typing
    return mapper;
}

@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "@class")
public static abstract class AssertionMixin {

    @JsonCreator
    AssertionMixin(final @JsonProperty("principal") AttributePrincipal principal) {
    }
}

@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "@class")
public static abstract class AttributePrincipalMixin {

    @JsonCreator
    AttributePrincipalMixin(final @JsonProperty("name") String name) {
    }
}

It works well!
@rwinch @christophstrobl Thanks for your help.

[christophstrobl]

thanks @FalconIA for letting us know! glad it works!

[rwinch]

@FalconIA Awesome! Given your feedback I'm going to close this.