Provide read/write customization hooks for GenericJackson2JsonRedisSerializer

[ashraf-revo]

ObjectMapper provide writerWithView method for controlling which property to be serialize this make us able to adjust and make sure which properties written to the cache server
for example

public class User {
    @JsonView(Views.Basic.class)
    public int id;
    @JsonView(Views.Basic.class)
    public String name;
    @JsonView(Views.Detailed.class)
    public String email;
    @JsonView(Views.Detailed.class)
    public String mobile;
}


public class Views {
    public static class Basic {
    }
    public static class Detailed {
    }
    public static class ViewBasic extends Basic{
    }
    public static class ViewDetailed extends ViewBasic , Detailed {
    }
}

so if we want to cache only id,name we only pass ViewBasic to the WriterView

for example

objectMapper.writerWithView(Views.ViewBasic.class).writeValueAsBytes(user)

if we need basic+email,mobile we should pass ViewDetailed to the WriterView

easy fix

we could override GenericJackson2JsonRedisSerializer.serialize
with this code

    @Override
    public byte[] serialize(Object source) throws SerializationException {
        if (source == null) {
            return EMPTY_ARRAY;
        }
        try {
            if (source instanceof CacheView) {
                CacheView cacheView = (CacheView) source;
                return cachingObjectMapper.writerWithView(cacheView.getCacheView()).writeValueAsBytes(source);
            } else {
                return cachingObjectMapper.writeValueAsBytes(source);
            }
        } catch (JsonProcessingException e) {
            throw new SerializationException("Could not write JSON: " + e.getMessage(), e);
        }
    }

---

    import com.fasterxml.jackson.annotation.JsonIgnore;

    public interface CacheView {
        @JsonIgnore
        Class<?> getCacheView();
    }

---

public class User implements Serializable, CacheView{
    @JsonView(Views.Basic.class)
    public int id;
    @JsonView(Views.Basic.class)
    public String name;
    @JsonView(Views.Detailed.class)
    public String email;
    @JsonView(Views.Detailed.class)
    public String mobile;

    private Class<?> cacheView;

}

[mp911de]

Right now, the contextual scope is a bit unclear. ObjectWriter instances can be obtained through various means. An approach could be providing reading- and writing functions (something along the lines of BiFunction<Object, ObjectMapper, byte[]>).

For the time being, subclassing and implementing the detail in a subclass would be the best workaround.

[ashraf-revo]

hi @mp911de thanks for you response
the problem not with passing ObjectWriter its about passing writerWithView value that will differ every time to control which property serialize to the cache server

[mp911de]

Related ticket: FasterXML/jackson-databind#3506 to enable ObjectMapper reuse.

[ashraf-revo]

hi @mp911de thank you for this big effort in implementing this task
i think we not need the read customization we care alot about the write customization because the data already written to the cache server with the write customization and the GenericJackson2JsonRedisSerializer will fetch all the data from the cache server that already written with write customization
we care about the the write customization because we can have control on which property should be written to the server , fix jackson infinite recursion (stackoverflowerror) , only cache data that not having security issue