ruststream 0.4.0

Async messaging framework for Rust: broker-agnostic traits, router, codecs, and a conformance harness for broker authors.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57

//! CBOR codec backed by [`ciborium`].

use bytes::{BufMut, BytesMut};
use serde::{Serialize, de::DeserializeOwned};

use crate::codec::{Codec, CodecError};

/// A `ciborium`-based [`Codec`]. Stateless; clone freely.
#[derive(Debug, Clone, Copy, Default)]
pub struct CborCodec;

impl Codec for CborCodec {
    fn encode<T: Serialize>(&self, value: &T) -> Result<BytesMut, CodecError> {
        // Serialize straight into the BytesMut writer: one buffer, no Vec-to-Bytes hop.
        let mut buf = BytesMut::new();
        ciborium::into_writer(value, (&mut buf).writer())
            .map_err(|err| CodecError::Encode(Box::new(err)))?;
        Ok(buf)
    }

    fn decode<T: DeserializeOwned>(&self, bytes: &[u8]) -> Result<T, CodecError> {
        ciborium::from_reader(bytes).map_err(|err| CodecError::Decode(Box::new(err)))
    }
}

#[cfg(test)]
mod tests {
    use serde::{Deserialize, Serialize};

    use super::*;

    #[derive(Debug, Serialize, Deserialize, PartialEq)]
    struct Sample {
        id: u32,
        name: String,
    }

    #[test]
    fn cbor_roundtrip() {
        let codec = CborCodec;
        let value = Sample {
            id: 12,
            name: "cbor".into(),
        };
        let bytes = codec.encode(&value).unwrap();
        let back: Sample = codec.decode(&bytes).unwrap();
        assert_eq!(back, value);
    }

    #[test]
    fn cbor_decode_error_surfaces() {
        let codec = CborCodec;
        // 0xff is the CBOR "break" code; not a complete top-level item.
        let err = codec.decode::<Sample>(b"\xff").unwrap_err();
        assert!(matches!(err, CodecError::Decode(_)));
    }
}