cbor2-cli

The cbor command line tool for CBOR (RFC 8949), built on the cbor2 crate:

cargo install cbor2-cli   # installs the `cbor` binary

Or install it from the ldclabs Homebrew tap:

brew install ldclabs/tap/cbor2-cli   # installs the `cbor` binary

Usage: cbor [COMMAND] [INPUT]

Commands:
  (none)  Show each CBOR item as one line of diagnostic notation (§8)
  decode  Convert CBOR items to pretty-printed JSON, or to
          pretty-printed diagnostic notation with --diag
  encode  Convert JSON values to CBOR items

INPUT is a file path, a hex string (optionally 0x-prefixed), a base64/base64url string, or - for stdin; stdin is the default. An argument containing a path separator is always a file path. Everything streams: multiple JSON values become a CBOR sequence (RFC 8742), and a CBOR sequence becomes one output document or line per item. Data errors exit with status 1, usage errors with status 2.

Show: cbor

The everyday command. It renders each item as the human-readable text form of RFC 8949 §8 — what CBOR specs and test vectors are written in — and it is exact: every item is captured as its wire bytes, so indefinite-length items keep their _ markers, segmented strings appear as (_ ...), undefined and unassigned simple values appear as themselves, byte strings render as h'...' and bignums print as plain integers, exactly as in RFC 8949 Appendix A.

$ cbor a201020326                  # hex, pasted straight from a spec
{1: 2, 3: -7}

$ cbor 0x8301820203820405          # 0x-prefixed works too
[1, [2, 3], [4, 5]]

$ cbor oWFhAQ                      # base64url, padded or not
{"a": 1}

$ cbor message.cbor                # a file
16([h'a1010a', {5: h'89f52f65a1c580933b5261a78c'}, h'5974e1b9...'])

$ cbor bf61610161629f0203ffff      # wire details survive
{_ "a": 1, "b": [_ 2, 3]}

decode

cbor decode decodes each item into the data model and pretty-prints it as JSON, or — with -d/--diag — as indented diagnostic notation. Unlike the bare cbor, this re-spells the item (indefinite lengths and non-preferred encodings are not preserved).

$ cbor decode a1018202036466697665f5
{
  "1": [
    2,
    3
  ]
}
"five"
true

$ cbor decode --diag a101820203
{
  1: [
    2,
    3
  ]
}

JSON conversion is best-effort where CBOR is richer: byte strings become lowercase hex strings, non-string map keys are JSON-encoded into strings, non-finite floats and undefined become null, integers beyond the 64-bit ranges become strings, and tags are dropped (keeping the inner value).

encode

cbor encode reads JSON text (from a file or stdin) and writes each value as a CBOR item:

$ echo '{"name": "example", "ok": true}' | cbor encode | cbor
{"name": "example", "ok": true}

$ echo '{"name": "example", "ok": true}' | cbor encode | xxd -p
a2646e616d65676578616d706c65626f6bf5

License

Dual-licensed under MIT or the UNLICENSE.