# dbc

dbc.DATABASE_FLAG_J1939 = 1

## Dbc

class canlib.kvadblib.Dbc(filename=None, name=None, protocol=None)

  Holds a dbc database.

  There are three ways to create a database:

  1. To load data from an existing database file, only set filename to the database filename.

  2. To add an empty database, set only name.

  3. To load data from an existing database file and give it a new name, set name to the new name and filename to the existing database filename.

  Either a name or a filename must be given.

  Parameters

    - filename (str, optional) – The existing database file is read.

    - name (str, optional) – The database name will be set.

  Raises

    KvdDbFileParse – If the database file can’t be parsed.

  When parsing a database file fails, `get_last_parse_error` can be called:

      try:
          kvadblib.Dbc(filename="database.dbc")
      except kvadblib.KvdDbFileParse:
          print(kvadblib.get_last_parse_error())

  Changed in version 1.10: `Dbc` now raises specific errors depending on the situation.

  attribute_definitions()

    Return a generator over all database attribute definitions.

  attributes()

    Return a generator over all database attributes.

    New in version 1.6.

  close()

    Close an open database handle.

  delete_attribute(name)

    Delete attribute from database.

    New in version 1.6.

  delete_attribute_definition(name)

    Delete attribute definition from database.

    New in version 1.7.

  delete_message(message)

    Delete message from database.

    Parameters

      message (`Message`) – message to be deleted

  delete_node(node)

    Delete node from database.

    Parameters

      node (`Node`) – node to be deleted

  property flags

    Get the database flags.

    E.g. DATABASE_FLAG_J1939

  get_attribute_definition_by_name(name)

    Find attribute definition using name.

    Parameters

      name (str) – name of attribute definition

    Returns an attribute definition object depending on type, e.g. if the type is AttributeType.INTEGER, an `IntegerAttributeDefinition` is returned.

  get_attribute_value(name)

    Return attribute value

    If the attribute is not set on the database, we return the attribute definition default value.

    New in version 1.6.

  get_message(id=None, name=None)

    Find message by id or name

    If both id and name is given, both most match.

    Note that bit 31 of the id indicates if the message has an extended id or not.

    Parameters

      - id (int) – message id to look for

      - name (str) – message name to look for

    Returns

      `Message`

    Raises

      KvdNoMessage – If no match was found, or if none of `id` and `name` were given.

  get_message_by_id(id, flags)

    Find message by id.

    Parameters

      - id (int) – message id to look for

      - flags (int) – message flags, e.g. `kvadblib.MessageFlag.EXT` (Note that `kvadblib.MessageFlag.EXT` != `canlib.MessageFlag.EXT`)

    Returns

      `Message`

    Raises

      KvdNoMessage – If no match was found.

  get_message_by_name(name)

    Find message by name

    Parameters

      name (str) – message name to look for

    Returns

      `Message`

    Raises

      KvdNoMessage – If no match was found.

  get_message_by_pgn(can_id)

    Find message using the PGN part of the given CAN id.

    Note

    The `can_id` must have the `MessageFlag.EXT` flag bit set (bit 31, 0x80000000)

        dbc = kvadblib.Dbc("My_j1939_database.dbc")
        can_id = 0xff4200
        can_id |= kvadblib.MessageFlag.EXT
        dbc.get_message_by_pgn(can_id)

    Parameters

      can_id (int) – CAN id containing PGN to look for

    Returns

      `Message`

    Raises

      KvdNoMessage – If no match was found.

    New in version 1.18.

  get_node_by_name(name)

    Find node by name

    Parameters

      name (str) – node name to look for

    Returns

      `Node`

    Raises

      KvdNoNode – If no match was found.

  interpret(frame, j1939=False)

    Interprets a given `canlib.Frame` object, returning a `BoundMessage`.

  messages(show_all=True)

    Return a generator of all database messages.

    If you would like to omit the special message ‘VECTOR__INDEPENDENT_SIG_MSG’, which is used to collect removed signals under, set show_all to False or use the Dbc iterator directly:

        db = kvadblib.Dbc(filename='mydb.dbc')
        for message in db:
            print(msg)

    Parameters

      show_all (`bool`) – If true, all messages, including any special message such as ‘VECTOR__INDEPENDENT_SIG_MSG’ will be returned

    Changed in version 1.8: Added argument show_all.

  property name

    The current database name (read-only)

    Type

      `str`

  new_attribute_definition(name, owner, type, definition)

    Create a new attribute definition in the database.

    The owner specify where the attribute is applicable, e.g. `AttributeOwner.MESSAGE` specifies that this attribute is only applicable on messages (`Message`).

    Parameters

      - name (str) – a unique name.

      - owner (`AttributeOwner`) – the owner type

    Returns

      `AttributeDefinition`

  new_message(name, id, flags=0, dlc=None, comment=None)

    Create a new message in the database.

    Parameters

      - name (str) – name of message

      - id (int) – message id

      - flags (int, optional) – message flags, e.g. `kvadblib.MessageFlag.EXT`

    Returns

      `Message`

  new_node(name, comment=None)

    Create a new node in the database.

    Parameters

      - name (str) – name of message

      - comment (str, optional) – message comment

    Returns

      `Node`

  node_in_signal(node, signal)

    Check if signal has been added to node.

    Returns

      True – signals contains node False: otherwise

  nodes()

    Return a generator containing all database nodes.

  property protocol

    The database protocol

    Type

      `ProtocolType`

  set_attribute_value(name, value)

    Set value of attribute name on database.

    If no attribute called name is set on database, attach a database attribute from the database attribute definition first.

    New in version 1.6.

  write_file(filename)

    Write a database to file.

    Parameters

      filename (str) – file to write database to

## get_last_parse_error()

canlib.kvadblib.get_last_parse_error()

  Can be used to get the specific reason why `KvdDbFileParse` was raised.

  Returns

    `str` – Error message from the parser.

  New in version 1.10.