Class ChangeHeaderNodelet

Inheritance Relationships

Base Type

  • public cras::Nodelet

Class Documentation

class ChangeHeaderNodelet : public cras::Nodelet

Nodelet for relaying messages and changing their header.

ROS parameters:

  • ~in_queue_size (uint, default 10): Queue size for the subscriber.

  • ~out_queue_size (uint, default $in_queue_size): Queue size for the publisher.

  • ~lazy (bool, default False): Whether to shut down the subscriber when the publisher has no subscribers. The ~input topic will be subscribed in the beginning, and will unsubscribe automatically after the first message is received (this is needed to determine the full type of the topic to publish).

  • ~tcp_no_delay (bool, default False): If True, the TCP_NODELAY flag is set for the subscriber. This should decrease the latency of small messages, but might give suboptimal transmission speed for large messages.

  • ~frame_id_prefix (string, no default): If set, frame_id will be prefixed with this string.

  • ~frame_id_suffix (string, no default): If set, frame_id will be suffixed with this string.

  • ~frame_id (string, no default): If set, frame_id will be replaced by this string.

  • ~frame_id_replace_start (string “from|to”, no default): If set and frame_id starts with from, it will be replaced with to.

  • ~frame_id_replace_end (string “from|to”, no default): If set and frame_id ends with from, it will be replaced with to.

  • ~frame_id_replace (string “from|to”, no default): If set, all occurrences of from in frame_id will be replaced with to.

  • ~stamp_relative (double, no default): If set, the given duration will be added to the message’s stamp. If the stamp would under/overflow, ros::TIME_MIN or ros::TIME_MAX will be set.

  • ~stamp (double, no default): If set, the message’s stamp will be set to this time (stamp_relative will not apply if set).

  • ~stamp_ros_time (bool, default false): If true, message stamp will be changed to current ROS time. stamp_relativecan be used in combination with this option. -~stamp_wall_time (bool, default false): If true, message stamp will be changed to current wall time. stamp_relative can be used in combination with this option.

Subscribed topics:

  • ~input (any type with header): The input messages. If lazy is true, it will only be subscribed when ~output has some subscribers. If you subscribe to a message type without header, the node should not crash, but it will discard all received messages and print an error message.

Published topics:

  • ~output (same type as ~input): The relayed output messages with changed header.

Command-line arguments: This nodelet (or node) can also be called in a way backwards compatible with topic_tools/relay. This means you can pass CLI arguments specifying the topics to subscribe/publish.

  • rosrun cras_topic_tools relay TOPIC_IN [TOPIC_OUT]

    • TOPIC_IN: The topic to subscribe. It is resolved against parent namespace of the node(let) (as opposed to the ~input topic which is resolved against the private node(let) namespace).

    • TOPIC_OUT: The topic to publish. It is resolved against parent namespace of the node(let) (as opposed to the ~output topic which is resolved against the private node(let) namespace). If not specified, output topic will be ${TOPIC_IN}_relay.

Note

A copy of the received message will be made in any case to allow modification of the header. If you set frame_id to a longer string, another copy of the message will be made to make space for the prolonged ID.

Protected Functions

void onInit() override
virtual void processMessage(const ::ros::MessageEvent<const ::topic_tools::ShapeShifter> &event, ::ros::Publisher &pub)

Change the header of the incoming message and publish the result.

Parameters:

  • event – [in] Event containing the received message.

  • pub – [in] The publisher to use for publishing.

Protected Attributes

::std::unique_ptr<::cras::GenericLazyPubSub> pubSub

The lazy pair of subscriber and publisher.

::cras::optional<::std::string> newFrameId

Replace the whole frame_id with this value.

::cras::optional<::std::string> newFrameIdPrefix

Prefix frame_id with this value.

::cras::optional<::std::string> newFrameIdSuffix

Suffix frame_id with this value.

::cras::optional<::std::pair<::std::string, ::std::string>> newFrameIdReplace

Replace all occurrences of first string with the second one in frame_id.

::cras::optional<::std::pair<::std::string, ::std::string>> newFrameIdReplaceStart

If frame_id starts with the first string, replace it with the second one.

::cras::optional<::std::pair<::std::string, ::std::string>> newFrameIdReplaceEnd

If frame_id ends with the first string, replace it with the second one.

::cras::optional<::ros::Time> newStampAbs

Replace stamp with the given value.

::cras::optional<::ros::Duration> newStampRel

Add this value to stamp. In case of under/overflow, TIME_MIN or TIME_MAX are set.

bool newStampRosTime = {false}

Change stamp to current ROS time.

bool newStampWallTime = {false}

Change stamp to current wall time.

::cras::optional<bool> hasHeader = {::cras::nullopt}

Whether the subscribed topic has a header field. This is filled on receipt of the first message.