Example:
import cborious
type Msg = object
greeting: string
value: int
let enc = toCbor(Msg(greeting: "hi", value: 42))
let dec = fromCbor(enc, Msg)Feedback welcome—API ergonomics, tag coverage, and real‑world use cases especially!
The performance seems pretty decent:
# nim c -d:release -r tests/bench_cbor.nim
Benchmarking with iters=10000
cborious: one-shot size=41 bytes repr=@[164, 98, 105, 100, 24, 42, 100, 110, 97, 109, 101, 104, 78, 105, 109, 32, 85, 115, 101, 114, 102, 97, 99, 116, 105, 118, 101, 245, 102, 115, 99, 111, 114, 101, 115, 133, 1, 2, 3, 5, 8]
cbor_serialization: one-shot size=41 bytes repr=@[164, 98, 105, 100, 24, 42, 100, 110, 97, 109, 101, 104, 78, 105, 109, 32, 85, 115, 101, 114, 102, 97, 99, 116, 105, 118, 101, 245, 102, 115, 99, 111, 114, 101, 115, 133, 1, 2, 3, 5, 8]
cbor_em: one-shot size=41 bytes repr=@[164, 98, 105, 100, 24, 42, 100, 110, 97, 109, 101, 104, 78, 105, 109, 32, 85, 115, 101, 114, 102, 97, 99, 116, 105, 118, 101, 245, 102, 115, 99, 111, 114, 101, 115, 133, 1, 2, 3, 5, 8]
--- Results (encode + decode round-trip) ---
cborious: avg=61100 ns/op total=611 ms
cbor_serialization: avg=108131 ns/op total=1081 ms
cbor_em: avg=103738 ns/op total=1037 ms
cbor_serialization/cborious: 1.77x for 10000 iterations
cbor_em/cborious: 1.70x for 10000 iterations
# nim c -d:release -r "tests/bench_cbor_simple.nim"
Benchmarking with iters=10000
cborious: one-shot size=25 bytes repr=@[135, 24, 42, 24, 100, 245, 24, 100, 251, 64, 5, 191, 9, 149, 170, 247, 144, 250, 64, 73, 14, 86, 130, 1, 2]
cbor_serialization: one-shot size=88 bytes repr=@[167, 102, 70, 105, 101, 108, 100, 48, 24, 42, 102, 70, 105, 101, 108, 100, 49, 24, 100, 102, 70, 105, 101, 108, 100, 50, 245, 102, 70, 105, 101, 108, 100, 51, 24, 100, 102, 70, 105, 101, 108, 100, 52, 251, 64, 5, 191, 9, 149, 170, 247, 144, 102, 70, 105, 101, 108, 100, 53, 250, 64, 73, 14, 86, 102, 70, 105, 101, 108, 100, 54, 162, 102, 70, 105, 101, 108, 100, 48, 1, 102, 70, 105, 101, 108, 100, 49, 2]
cbor_em: one-shot size=25 bytes repr=@[135, 24, 42, 24, 100, 245, 24, 100, 251, 64, 5, 191, 9, 149, 170, 247, 144, 250, 64, 73, 14, 86, 130, 1, 2]
--- Results (encode + decode round-trip) ---
cborious: avg=30962 ns/op total=309 ms
cbor_serialization: avg=207246 ns/op total=2072 ms
cbor_em: avg=46876 ns/op total=468 ms
cbor_serialization/cborious: 6.69x for 10000 iterations
cbor_em/cborious: 1.51x for 10000 iterationsDazzling, I remember when I started Rust, I tried to encode some data with cbor, to increase performance.
Found only discontinued serde_cbor, others were too complicated to use. I understand Rust developers implementing concise code, but you could write two classes of code. One with whatever custom, concise operations you want, and one for simple one-liner operation, like this library implements with toCbor(), fromCbor() 👍🏻👍🏻
That led me down a bit of a rabbit hole looking into Rust's CBOR world. It looks rough... The top cbor crates are archived, and the new ones look all over the place. All 3 Nim CBOR libs look to be more complete and easier to use. Obviously Cborious is the most complete! It implements self-describing CBOR ;)
Actually I quite enjoy that a few hours of prompting GPT5 on a side project can be so productive with Nim. Truth be told I was using making Cborious as a way to get over "writers block" in the mornings! Helps me overcome procrastination.
Release 0.7.1 of Cborious adds an implementation of "typed arrays" for CBOR from RFC4786. It's intended to allow skipping parsing large numerical arrays.
Here's an example showing the bytes output and that it only adds ~4 bytes of overhead in this case.
let dataIn = @[1.0'f64, -2.0'f64, 3.5'f64]
# Little-endian float64 typed array (tag 86)
var sLe = CborStream.init()
sLe.cborPackTypedArray(dataIn)
let hexLe = sLe.data.toBytes().toHexPretty()
# D8 56 58 18 then three little-endian IEEE 754 binary64 values:
# 1.0 -> 00 00 00 00 00 00 F0 3F
# -2.0 -> 00 00 00 00 00 00 00 C0
# 3.5 -> 00 00 00 00 00 00 0C 40
check hexLe == "D8 56 58 18 00 00 00 00 00 00 F0 3F 00 00 00 00 00 00 00 C0 00 00 00 00 00 00 0C 40"
var outLe: seq[float64]
var stLe2 = CborStream.init(sLe.data)
stLe2.cborUnpackTypedArray(outLe, littleEndian)
check outLe.len == dataIn.len
when system.cpuEndian == bigEndian:
for item in outBe.mitems():
swapEndian64(addr(item), addr(item))
check outLe == dataInFor usage see: https://github.com/elcritch/cborious/blob/main/tests/ttypedarrays.nim