CBOR

local cbor = require("nauthilus_cbor")

The nauthilus_cbor module exposes the same CBOR policy used by the HTTP authentication endpoint. It can encode Lua values to a CBOR byte string and decode CBOR byte strings back into Lua values.

Supported Values

Decoded CBOR values are converted to Lua as follows:

CBOR value	Lua value
null	cbor.null
boolean	boolean
text string	string
byte string	string
integer	number
floating point	number
array	table with consecutive numeric keys
map	table

When encoding Lua values:

• nil becomes CBOR null.
• booleans, strings, numbers, arrays, and maps are supported.
• integer Lua numbers are encoded as integers; non-integer numbers are encoded as floating point values.
• array tables use consecutive numeric keys from 1 to #table.
• map tables use string keys; integer numeric keys are converted to string keys.
• cbor.bytes(value) marks a Lua string for CBOR byte-string encoding.
• cbor.null can be used when a table needs an explicit null value.

cbor.decode

Decodes a CBOR byte string.

Syntax

local value, err = cbor.decode(payload)

Parameters

• payload (string): CBOR bytes.

Returns

• value (any): The decoded Lua value, or nil on error.
• err (string): Error text, or nil on success.

Example

local cbor = require("nauthilus_cbor")

local value, err = cbor.decode(request_body)
if err ~= nil then
  return nauthilus_builtin.custom_log("CBOR decode failed: " .. err)
end

if value.optional_field == cbor.null then
  value.optional_field = nil
end

cbor.encode

Encodes a Lua value as a CBOR byte string.

Syntax

local payload, err = cbor.encode(value)

Parameters

• value (any): Lua value to encode.

Returns

• payload (string): Encoded CBOR bytes, or nil on error.
• err (string): Error text, or nil on success.

Example

local cbor = require("nauthilus_cbor")

local payload, err = cbor.encode({
  username = "alice@example.test",
  ok = true,
  attributes = {
    "mail",
    "uid",
  },
  binary = cbor.bytes("\001\002\003"),
  absent = cbor.null,
})

if err ~= nil then
  return nauthilus_builtin.custom_log("CBOR encode failed: " .. err)
end

cbor.bytes

Marks a Lua string as a CBOR byte string during encoding. Without this marker, Lua strings are encoded as CBOR text strings.

Syntax

local bytes = cbor.bytes(value)

Parameters

• value (string): Bytes stored in a Lua string.

Returns

• bytes (userdata): A byte-string marker accepted by cbor.encode.

cbor.null

cbor.null is a stable sentinel for explicit CBOR null values. It is useful when null must be preserved inside a Lua table because plain Lua nil removes a table key.