How to serialize JNothing as null

Question

With lift-json backed json4s, if I do the following:

val foobar = ("foo" -> JNothing) ~ ("bar" -> 42) 
println(write(foobar))

The output is:

{, "bar":42}

which is not valid JSON. I would like to obtain:

{"foo":null, "bar":42}

Is there any way to serialize JNothing into null?

why do you need that? No foo element means it is `null` already — Tala, Jul 08 '13 at 08:16
@Tala: the deserializer at the other end is expecting it, as a mandatory value that can be null. — Eduardo, Jul 08 '13 at 08:20
Ussually this is overcome by setting `null` by default to these fields — Tala, Jul 08 '13 at 08:35
@Tala: if I had control over the receiving end, sure. However, I am required to send {"foo":null, "bar":42} — Eduardo, Jul 08 '13 at 08:44
I'd say that producing invalid JSON is a bug which should be reported... — Alexey Romanov, Jul 08 '13 at 11:31
@AlexeyRomanov: I am not sure if I am using `write` correctly, though. If I do `compact(render(foobar))` the output is correct. — Eduardo, Jul 08 '13 at 12:55
I came across the same issue the other day. It's definitely a bug in json4s, so I filed an issue https://github.com/json4s/json4s/issues/114 — mjaskowski, Apr 13 '14 at 17:52

score 2 · Accepted Answer · answered Jul 08 '13 at 08:55

2

I have found that, if I replace JNothing for JNull, I get the results that I expect.

answered Jul 08 '13 at 08:55

Eduardo

1 Answers1