CBOR data format

Q: How do I convert CBOR to JSON?

unmarshal: {cbor: {}} then marshal: {json: {}}.

The cbor data format encodes the message body as CBOR, a compact binary form of JSON (RFC 8949), and decodes CBOR back into a structured body.

Name: cbor · Crate: cameleer-dataformats · Cargo feature: dataformats · Apache Camel: CBOR

When to use it

Send sensor readings from constrained devices: CBOR is smaller than JSON and is the payload format of CoAP, LwM2M and many IoT stacks.
Read CBOR from WebAuthn/COSE messages or devices, and turn it into JSON for the cloud side.
Shrink JSON-like payloads on edge links without a schema.

Marshal and unmarshal

direction	body in	body out
`marshal`	any value (objects, lists, strings, numbers, booleans, null, bytes)	CBOR bytes, preferred serialization (shortest integers; floats as half, single or double precision, whichever is exact)
`unmarshal`	CBOR bytes (empty gives null)	a structured value. Indefinite lengths are supported; bignums become integers when they fit, else decimal strings; other tags are dropped.

marshal encodes the body as it is: a JSON text body becomes a CBOR text string, so unmarshal the JSON first.

Example

Encode a reading and show the CBOR bytes (13 bytes, against 23 for the JSON text):

yaml example: cbor-encode

- route:
    id: cbor-encode
    from:
      uri: direct:cbor-encode
      steps:
        - unmarshal:
            json: {}
        - marshal:
            cbor: {}
        - marshal:
            hex: {}

json

{"temp":21.5,"ok":true}

text

a26474656d70f94d60626f6bf5

Decode CBOR from a device back to JSON:

yaml example: cbor-decode

- route:
    id: cbor-decode
    from:
      uri: direct:cbor-decode
      steps:
        - unmarshal:
            hex: {}
        - unmarshal:
            cbor: {}
        - marshal:
            json: {}

text

a26474656d70f94d60626f6bf5

json

{"temp":21.5,"ok":true}

Rust DSL

rust

b.from("direct:cbor-rust")
    .marshal(DataFormatDefinition::new("cbor"))
    .unmarshal(DataFormatDefinition::new("cbor"));

Options

None. Camel's options (unmarshalType, useList, allowJmsType...) are accepted and ignored: CBOR always maps to a generic value.

Common questions

How much smaller is CBOR than JSON?

Usually 20-50% for small messages: keys and numbers are stored in binary, without quotes or separators. Compress it as well for large payloads.

How do I convert CBOR to JSON?

unmarshal: {cbor: {}} then marshal: {json: {}}.

Found a problem?

If something on this page doesn't match what Cameleer does, or you hit a bug while building with it, please help fix it, whether you are a person or a coding agent: open an issue that describes what you saw, then fork the repository, fix it, add or update a test, run cargo test --workspace, and open a pull request. CONTRIBUTING.md explains the ground rules.