Datum

class cometa.common.datum.Datum(ptr)[source]

Bases: object

Represents a piece of data attached to a UTxO for Plutus script interaction.

Datums act as state for UTxOs, allowing Plutus scripts to perform complex logic based on stored data when the UTxO is being spent. There are two types:

DATA_HASH: A hash reference to off-chain datum data
INLINE_DATA: The actual Plutus data stored directly on-chain

Example

>>> datum = Datum.from_data_hash_hex("00" * 32)
>>> datum.datum_type
DatumType.DATA_HASH

__init__(ptr)[source]

Return type:: None

__enter__()[source]

Return type:: Datum

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

Return type:: None

__repr__()[source]

Return repr(self).

Return type:: str

classmethod from_data_hash(hash_value)[source]

Creates a datum from a Blake2b hash reference.

Parameters:: hash_value (Blake2bHash) – The Blake2b hash of the datum data.
Returns:: A new Datum instance with type DATA_HASH.
Raises:: CardanoError – If creation fails.
Return type:: Datum

Example

>>> hash_val = Blake2bHash.from_hex("00" * 32)
>>> datum = Datum.from_data_hash(hash_val)

classmethod from_data_hash_hex(hex_string)[source]

Creates a datum from a hexadecimal hash string.

Parameters:: hex_string (str) – The hash as a hexadecimal string.
Returns:: A new Datum instance with type DATA_HASH.
Raises:: CardanoError – If creation fails or hash is invalid.
Return type:: Datum

Example

>>> datum = Datum.from_data_hash_hex("abcd1234" * 8)

classmethod from_data_hash_bytes(data)[source]

Creates a datum from raw hash bytes.

Parameters:: data (bytes | bytearray) – The hash as raw bytes.
Returns:: A new Datum instance with type DATA_HASH.
Raises:: CardanoError – If creation fails.
Return type:: Datum

Example

>>> datum = Datum.from_data_hash_bytes(bytes(32))

classmethod from_inline_data(data)[source]

Creates a datum from inline Plutus data.

Parameters:: data – The Plutus data to store inline (PlutusData instance).
Returns:: A new Datum instance with type INLINE_DATA.
Raises:: CardanoError – If creation fails.
Return type:: Datum

Example

>>> plutus_data = PlutusData.from_int(42)
>>> datum = Datum.from_inline_data(plutus_data)

classmethod from_cbor(reader)[source]

Deserializes a Datum from CBOR data.

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

property datum_type: DatumType: Returns the type of this datum (DATA_HASH or INLINE_DATA).

property data_hash: Blake2bHash | None

Returns the hash associated with this datum.

Returns None if this is an inline datum without a hash.

property data_hash_hex: str: Returns the data hash as a hexadecimal string.

property data_hash_bytes: bytes: Returns the data hash as raw bytes.

get_inline_data()[source]

Returns the inline Plutus data if this is an inline datum.

Returns None if this is a data hash datum.

Note: This method requires the PlutusData module to be available. Import PlutusData from cometa.plutus_data before calling this method.

Raises:: ImportError – If PlutusData module is not available.

to_cbor(writer)[source]

Serializes the datum to CBOR format.

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

to_cip116_json(writer)[source]

Converts this object to CIP-116 compliant JSON representation.

CIP-116 defines a standard JSON format for Cardano data structures.

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

__eq__(other)[source]

Checks equality with another Datum.

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

__hash__()[source]

Returns a Python hash for use in sets and dicts.

Return type:: int

__str__()[source]

Returns a string representation of the datum.

Return type:: str