How to implement programmatic view serialization to enable "fields" query parameter in REST API

[sareykaj]

Hi,
I am looking for a way to implement a "fields" query parameter to apply a dynamic projection or view on the serialized json response payload in a REST API. E.g., GET http://api.example.org/users/123?fields=(name,friends(name)) would return only the name of the user and the name property within the nested list of friends. While this could be implemented at design time with a @JSONVIEW interface, the fields query parameter needs to be evaluated at runtime. I have found the project "Programmatic JSON Views" (https://github.com/monitorjbl/json-view) that implements something in that direction but it seems to be no longer maintained. Is there any built in feature in Jackson (or Spring Boot REST). Or do you know any framework that is still maintained?
Thanks, Julian

[cowtowncoder]

Another mechanism would be use of @JsonFilter which could work:

http://www.cowtowncoder.com/blog/archives/2011/09/entry_461.html

[sareykaj]

@cowtowncoder , thanks for the hint. Is it already possible to implement filtering for nested properties. From what I could extract here FasterXML/jackson-databind#1040, the issue was closed without providing a fix.

[cowtowncoder]

It is possible to filter nested properties, but not using path expressions. That is, all filtering is by immediate properties of POJO for which filter is applied -- there is no way to (f.ex) indicate dotted path starting from object.