rosros.ros1.Bag Class Reference

ROS1 bag reader and writer. More...

Inheritance diagram for rosros.ros1.Bag:

Public Member Functions
	__init__ (self, f, mode="r", compression=rosbag.Compression.NONE, chunk_threshold=768 *1024, allow_unindexed=False, options=None, skip_index=False)
	Opens a ROS1 bag file.
	get_message_class (self, typename, typehash=None)
	Returns ROS1 message class for typename, or None if unknown type.
	get_message_definition (self, msg_or_type)
	Returns ROS1 message type definition full text from bag, including subtype definitions.
	get_message_type_hash (self, msg_or_type)
	Returns ROS1 message type MD5 hash.
	get_qoses (self, topic, typename)
	Returns None (ROS2 bag API conformity stand-in).
	get_topic_info (self, *_, **__)
	Returns topic and message type metainfo as {(topic, typename, typehash): count}.
	read_messages (self, topics=None, start_time=None, end_time=None, connection_filter=None, raw=False)
	Yields messages from the bag in chronological order.
	write (self, topic, msg, t=None, raw=False, connection_header=None, **__)
	Writes a message to the bag.

Static Public Member Functions
	reindex_file (f)
	Reindexes bag file on disk.

Static Public Attributes
str	EXTENSION = ".bag"
	Default extension for bag files.

Detailed Description

ROS1 bag reader and writer.

Extends `rosbag.Bag` with more conveniences, and smooths over the rosbag bug of yielding messages of wrong type, if message types in different topics have different packages but identical fields and hashes.

Does **not** smooth over the rosbag bug of writing different types to one topic.

rosbag does allow writing messages of different types to one topic, just like live ROS topics can have multiple message types published to one topic. And their serialized bytes will actually be in the bag, but rosbag will only register the first type for this topic (unless it is explicitly given another connection header with metadata on the other type).

All messages yielded will be deserialized by rosbag as that first type, and whether reading will raise an exception or not depends on whether the other type has enough bytes to be deserialized as that first type.

Definition at line 126 of file ros1.py.

Constructor & Destructor Documentation

__init__()

rosros.ros1.Bag.__init__	(		self,
			f,
			mode = "r",
			compression = rosbag.Compression.NONE,
			chunk_threshold = 768 * 1024,
			allow_unindexed = False,
			options = None,
			skip_index = False
	)

Opens a ROS1 bag file.

Parameters

f	bag file path to open
mode	mode to open bag in, one of "r", "w", "a"
compression	bag write compression mode, one of Compression
chunk_threshold	minimum number of uncompressed bytes per chunk to write
allow_unindexed	allow opening unindexed bags
options	optional dict with values for "compression" and "chunk_threshold"
skip_index	skip reading the connection index records on open

Definition at line 161 of file ros1.py.

Member Function Documentation

get_message_class()

rosros.ros1.Bag.get_message_class	(		self,
			typename,
			typehash = None
	)

Returns ROS1 message class for typename, or None if unknown type.

Generates class dynamically if not already generated.

Parameters

typehash

message type definition hash, if any

Definition at line 185 of file ros1.py.

get_message_definition()

rosros.ros1.Bag.get_message_definition	(		self,
			msg_or_type
	)

Returns ROS1 message type definition full text from bag, including subtype definitions.

Definition at line 170 of file ros1.py.

get_message_type_hash()

rosros.ros1.Bag.get_message_type_hash	(		self,
			msg_or_type
	)

Returns ROS1 message type MD5 hash.

Definition at line 195 of file ros1.py.

get_qoses()

rosros.ros1.Bag.get_qoses	(		self,
			topic,
			typename
	)

Returns None (ROS2 bag API conformity stand-in).

Definition at line 206 of file ros1.py.

get_topic_info()

rosros.ros1.Bag.get_topic_info	(		self,
		*	_,
		**	__
	)

Returns topic and message type metainfo as {(topic, typename, typehash): count}.

Definition at line 211 of file ros1.py.

read_messages()

rosros.ros1.Bag.read_messages	(		self,
			topics = None,
			start_time = None,
			end_time = None,
			connection_filter = None,
			raw = False
	)

Yields messages from the bag in chronological order.

Parameters

topics	list of topics or a single topic. If an empty list is given, all topics will be read.
start_time	earliest timestamp of messages to return, as `rospy.Time` or convertible (int/float/duration/datetime/decimal)
end_time	latest timestamp of messages to return as `rospy.Time` or convertible (int/float/duration/datetime/decimal)
connection_filter	function to filter connections to include
raw	if True, then returned messages are tuples of (typename, bytes, md5sum, typeclass) or (typename, bytes, md5sum, position, typeclass), depending on file format version

Returns

generator of BagMessage(topic, message, timestamp) namedtuples

Definition at line 239 of file ros1.py.

reindex_file()

rosros.ros1.Bag.reindex_file (   f )

static

Reindexes bag file on disk.

Makes a temporary copy in file directory.

Definition at line 341 of file ros1.py.

write()

rosros.ros1.Bag.write	(		self,
			topic,
			msg,
			t = None,
			raw = False,
			connection_header = None,
		**	__
	)

Writes a message to the bag.

Parameters

topic	name of topic
msg	ROS message to write, or tuple if raw
t	message timestamp if not using current wall time, as `rospy.Time` or convertible (int/float/duration/datetime/decimal)
raw	if true, msg is expected as (typename, bytes, typehash, typeclass) or (typename, bytes, typehash, position, typeclass)
connection_header	custom connection header dict if any, as {"topic", "type", "md5sum", "message_definition"}

Definition at line 280 of file ros1.py.

Member Data Documentation

EXTENSION

str rosros.ros1.Bag.EXTENSION = ".bag"

static

Default extension for bag files.

Definition at line 129 of file ros1.py.

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The documentation for this class was generated from the following file:

• rosros/ros1.py