Metadatum

class cometa.auxiliary_data.metadatum.Metadatum(ptr)[source]

Bases: object

Represents a transaction metadatum in Cardano.

Metadatum can be one of five types: map, list, integer, bytes, or text. This is used to attach arbitrary data to transactions.

Example

>>> # Integer metadatum
>>> meta = Metadatum.from_int(42)
>>> meta.kind
<MetadatumKind.INTEGER: 2>

>>> # Text metadatum
>>> meta = Metadatum.from_string("Hello")
>>> meta.to_str()
'Hello'

__init__(ptr)[source]

Return type:: None

__enter__()[source]

Return type:: Metadatum

__exit__(exc_type, exc_val, exc_tb)[source]

Return type:: None

__repr__()[source]

Return repr(self).

Return type:: str

classmethod from_int(value)[source]

Creates a metadatum from a signed integer.

Parameters:: value (int) – The integer value.
Returns:: A new Metadatum containing the integer.
Raises:: CardanoError – If creation fails.
Return type:: Metadatum

Example

>>> meta = Metadatum.from_int(42)

classmethod from_uint(value)[source]

Creates a metadatum from an unsigned integer.

Parameters:: value (int) – The unsigned integer value.
Returns:: A new Metadatum containing the integer.
Raises:: CardanoError – If creation fails.
Return type:: Metadatum

classmethod from_integer_string(string, base=10)[source]

Creates a metadatum from a string representation of an integer.

This is useful for large integers that don’t fit in int64/uint64.

Parameters:

string (str) – The string representation of the integer.
base (int) – The numeric base (2-36). Defaults to 10.

Returns:

A new Metadatum containing the integer.

Raises:

CardanoError – If creation fails.

Return type:

Metadatum

Example

>>> meta = Metadatum.from_integer_string("12345678901234567890")

classmethod from_bigint(value)[source]

Creates a metadatum from a BigInt.

Parameters:: value (BigInt) – The BigInt value.
Returns:: A new Metadatum containing the integer.
Raises:: CardanoError – If creation fails.
Return type:: Metadatum

classmethod from_bytes(data)[source]

Creates a metadatum from bytes.

Parameters:: data (bytes | bytearray) – The byte data (max 64 bytes per chunk).
Returns:: A new Metadatum containing the bytes.
Raises:: CardanoError – If creation fails.
Return type:: Metadatum

Example

>>> meta = Metadatum.from_bytes(b"\xde\xad\xbe\xef")

classmethod from_hex(hex_string)[source]

Creates a metadatum from a hexadecimal string.

Parameters:: hex_string (str) – The hex-encoded bytes.
Returns:: A new Metadatum containing the bytes.
Raises:: CardanoError – If creation fails.
Return type:: Metadatum

Example

>>> meta = Metadatum.from_hex("deadbeef")

classmethod from_string(text)[source]

Creates a metadatum from a text string.

Parameters:: text (str) – The text string (max 64 bytes when UTF-8 encoded).
Returns:: A new Metadatum containing the text.
Raises:: CardanoError – If creation fails.
Return type:: Metadatum

Example

>>> meta = Metadatum.from_string("Hello, Cardano!")

classmethod from_cbor(reader)[source]

Deserializes a Metadatum from CBOR data.

Parameters:: reader (CborReader) – A CborReader positioned at the metadatum data.
Returns:: A new Metadatum deserialized from the CBOR data.
Raises:: CardanoError – If deserialization fails.
Return type:: Metadatum

classmethod from_json(json)[source]

Creates a metadatum from a JSON string.

Parameters:: json (str) – The JSON-encoded metadatum.
Returns:: A new Metadatum deserialized from the JSON data.
Raises:: CardanoError – If parsing fails.
Return type:: Metadatum

Example

>>> meta = Metadatum.from_json('{"int": 42}')

classmethod from_map(metadatum_map)[source]

Creates a metadatum from a MetadatumMap.

Parameters:: metadatum_map (MetadatumMap) – The MetadatumMap to convert.
Returns:: A new Metadatum containing the map.
Raises:: CardanoError – If creation fails.
Return type:: Metadatum

Example

>>> meta_map = MetadatumMap()
>>> meta_map.insert(Metadatum.from_string("key"), Metadatum.from_int(42))
>>> meta = Metadatum.from_map(meta_map)
>>> meta.kind
<MetadatumKind.MAP: 0>

classmethod from_list(metadatum_list)[source]

Creates a metadatum from a MetadatumList or a Python list.

Parameters:: metadatum_list (Union[MetadatumList, List[MetadatumLike]]) – The MetadatumList or a Python list of metadatum values to convert.
Returns:: A new Metadatum containing the list.
Raises:: CardanoError – If creation fails.
Return type:: Metadatum

Example

>>> meta_list = MetadatumList()
>>> meta_list.add(Metadatum.from_int(1))
>>> meta_list.add(Metadatum.from_int(2))
>>> meta = Metadatum.from_list(meta_list)
>>> meta.kind
<MetadatumKind.LIST: 1>

>>> # Or using a Python list directly
>>> meta = Metadatum.from_list([1, "hello", b"bytes"])

property kind: MetadatumKind

Returns the kind of this metadatum.

Returns:: The MetadatumKind enum value.

to_integer()[source]

Converts this metadatum to a BigInt.

Returns:: The BigInt value.
Raises:: CardanoError – If this metadatum is not an integer type.
Return type:: BigInt

to_bytes()[source]

Converts this metadatum to bytes.

Returns:: The byte data.
Raises:: CardanoError – If this metadatum is not a bytes type.
Return type:: bytes

to_str()[source]

Converts this metadatum to a string.

Returns:: The text string.
Raises:: CardanoError – If this metadatum is not a text type.
Return type:: str

to_json()[source]

Converts this metadatum to a JSON string.

Returns:: The JSON representation.
Return type:: str

to_map()[source]

Converts this metadatum to a MetadatumMap.

Returns:: The MetadatumMap representation.
Raises:: CardanoError – If this metadatum is not a map type.
Return type:: MetadatumMap

Example

>>> meta = Metadatum.from_map(some_map)
>>> retrieved_map = meta.to_map()

to_list()[source]

Converts this metadatum to a MetadatumList.

Returns:: The MetadatumList representation.
Raises:: CardanoError – If this metadatum is not a list type.
Return type:: MetadatumList

Example

>>> meta = Metadatum.from_list(some_list)
>>> retrieved_list = meta.to_list()

to_cip116_json(writer)[source]

Serializes this metadatum to CIP-116 JSON format.

CIP-116 defines a standard JSON representation for transaction metadata.

Parameters:: writer (JsonWriter) – A JsonWriter to write the serialized data to.
Raises:: CardanoError – If serialization fails.
Return type:: None

Example

>>> meta = Metadatum.from_int(42)
>>> writer = JsonWriter()
>>> meta.to_cip116_json(writer)
>>> json_str = writer.encode()

to_cbor(writer)[source]

Serializes the metadatum to CBOR format.

Parameters:: writer (CborWriter) – A CborWriter to write the serialized data to.
Raises:: CardanoError – If serialization fails.
Return type:: None

__eq__(other)[source]

Checks equality with another Metadatum.

Parameters:: other (object)
Return type:: bool

__hash__()[source]

Returns a hash based on JSON representation.

Return type:: int