oxml-json 0.0.8

A small JSON value, parser and serialiser for the oxml suite's JSON-RPC crates
Documentation
  • Coverage
  • 100%
    14 out of 14 items documented1 out of 8 items with examples
  • Size
  • Source code size: 79.6 kB This is the summed size of all the files inside the crates.io package for this release.
  • Documentation size: 290.6 kB This is the summed size of all files generated by rustdoc for all configured targets
  • Ø build duration
  • this release: 2s Average build duration of successful builds.
  • all releases: 2s Average build duration of successful builds in releases after 2024-10-23.
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  • sebastienrousseau

Why this exists

Two crates in the oxml suite speak JSON-RPC: oxml-mcp over the Model Context Protocol, and oxml-lsp over the Language Server Protocol. For a while each carried its own copy of this file, because neither could reach the other's private module.

A copy is fine until it is not. A defect fixed in one would not have reached the other, and nothing would have noticed — the failure mode this suite keeps finding elsewhere. So it lives here instead.

The extraction was worth it immediately. Moving the fuzz target here came with a stronger assertion — that anything which parses must survive a round trip — and it found a defect within ninety seconds that had been in both copies: 1e999 is grammatically valid JSON, parses to infinity, and infinity has no JSON representation, so serialising it produced output that would not parse. It is now refused, because writing null instead would silently change the value.

Scope

JSON-RPC messages are small and their shapes are fixed, so this implements what those protocols need rather than everything the grammar allows. It is not a general-purpose JSON library and does not try to be. If you want serde, use serde — it is better at this, and this crate exists to avoid a dependency in a specific place, not to compete.

Install

[dependencies]
oxml-json = "0.0.8"

Quick Start

use oxml_json::{parse, Json};

let value = parse(r#"{"jsonrpc":"2.0","id":1}"#).expect("valid JSON");
assert_eq!(value.get("jsonrpc").and_then(Json::as_str), Some("2.0"));

let reply = Json::object(vec![
    ("jsonrpc", Json::str("2.0")),
    ("id", Json::Number(1.0)),
]);
assert_eq!(reply.to_json(), r#"{"id":1,"jsonrpc":"2.0"}"#);

Object keys come back out in sorted order, which makes serialised output comparable in a test without parsing it again.

Numbers

Numbers are f64, which is what JSON's grammar describes and what both protocols use for ids and codes. An integer beyond 253 does not survive that, which no request id in either protocol reaches. A literal outside f64's range is refused rather than rounded to infinity.

Development

./scripts/gate.sh

Everything CI runs: format, clippy, tests, rustdoc, the #![forbid(unsafe_code)] check, the example, a 95% coverage floor and an MSRV build. Fuzzing runs in CI on every pull request.

Security

See SECURITY.md. This crate parses untrusted input by design — both protocols carry it — so it is fuzzed continuously and refuses malformed input rather than guessing at it.

License

Licensed under either of

at your option.