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.