olpc-cjson provides a serde_json::Formatter to serialize data as canonical JSON, as defined by OLPC and used in TUF. It is developed as part of tough, a Rust library for using TUF repositories.

OLPC's canonical JSON specification is subtly different from other "canonical JSON" specifications, and is also not a strict subset of JSON (specifically, ASCII control characters 0x00–0x1f are printed literally, which is not valid JSON). Therefore, serde_json cannot necessarily deserialize JSON produced by this formatter.

This crate is not developed or endorsed by OLPC; use of the term is solely to distinguish this specification of canonical JSON from other specifications of canonical JSON.

use olpc_cjson::CanonicalFormatter;
use serde::Serialize;
use serde_json::json;

let value = json!({"b": 12, "a": "qwerty"});
let mut buf = Vec::new();
let mut ser = serde_json::Serializer::with_formatter(&mut buf, CanonicalFormatter::new());
value.serialize(&mut ser).unwrap();
assert_eq!(buf, br#"{"a":"qwerty","b":12}"#);