Proper Object Graphs in JSON

[bep (Bjørn Erik Pedersen)]

I look into this every five years or so, and I get pretty disappointed whenever I check the current support for serializing and deserializing object graphs with proper reference handling (including circular refs) to and from JSON (or another suitable format, I guess …).

In Go’s builtin JSON encoder, you get a stack overflow: https://github.com/golang/go/issues/10769

I’m writing this application now that has a potentially very deep structure with lots of nodes. I have made some “glue code” on the client (Javascript) to keep track of both the references and the identities to the associations, so if I make a change related to a node on, say, level 3 – I only need to re-render 3 nodes (even if the tree has thousands, ReactJS is great for this).

This works, but gets ugly pretty fast.

I’m kind of surprised that this isn’t a standard in 2016. Am I missing something?

[Egon (Egon Elbre)]

Search for data-formats that natively support circular references. I.e. pretty easy to find:

package main

import (
	"fmt"
	"log"

	"github.com/Sereal/Sereal/Go/sereal"
)

type Node struct {
	ID   string
	Next *Node
}

func main() {
	send := &Node{"Hello", nil}
	send.Next = send

	data, err := sereal.Marshal(send)
	if err != nil {
		log.Fatal(err)
	}

	recv := &Node{}
	err = sereal.Unmarshal(data, &recv)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf("%p := %#v\n", send, send)
	fmt.Printf("%p := %#v\n", recv, recv)
}

Alternatively, just write your own encoding/schema for circular references – e.g. something that encodes to JSON, but flattens everything.