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ROS

ROS utils for use in Transitive robot capabilities. Supports both ROS 1 (using rosnodejs) and ROS 2 (using rclnodejs). The respective classes ROS1 and ROS2 have a unified interface, so that switching between ROS releases is trivial as can be seen in the example below.

Install​

npm i @transitive-sdk/utils-ros

Example​

This example requires a running roscore for ROS 1.

const { ROSs, getForVersion } = require('@transitive-sdk/utils-ros');

const demo = async (version) => {
  const ros = getForVersion(version);
  await ros.init();

  const topic = '/utils_ros/test1';
  const type = version == 1 ? 'std_msgs/String' : 'std_msgs/msg/String';

  const interval = setInterval(() => {
    ros.publish(topic, type, {data: String(Date.now())});
  });

  const sub = ros.subscribe(topic, type, (msg) => {
    console.log('received', msg.data);
  });
};

demo(1); // run demo using ROS1
demo(2); // run demo using ROS2

ROS​

Small convenient singleton class for interfacing with ROS, including some auxiliary functions that come in handy in capabilities. Based on rosnodejs.

callService​

Call the given service of the given type with the given body (not required when type is "std_srvs/Empty").

Parameters​
  • serviceName
  • type
  • requestBody (optional, default undefined)

createHeader​

create a std_msgs/Header for the given frame_id and date

Parameters​
  • frame_id (optional, default '')
  • date (optional, default new Date())

getAvailableTypes​

Get all known message and service types, grouped by package.

getServices​

Get available services (list of names).

getServiceType​

Get type of a given service. Note that in ROS 1 this requires connecting to the service provider directly, and we don't want to poll all of them. So only use this on-demand.

Parameters​
  • service

getSubscribedTopics​

Get topics that have subscribers

Parameters​
  • type (optional, default undefined)

getTopics​

Get all topic of a given type or all topics if no type is specified

Parameters​
  • type (optional, default undefined)

getTypeTemplate​

Given a package, category, and type, e.g., 'std_msgs', 'msg', and 'String', return a plain object representing that type, which can be used as a template for creating messages.

Parameters​
  • pkg
  • category
  • type
  • response (optional, default false)

init​

Initialize ROS node. This needs to be called first.

Parameters​
  • suffix (optional, default '')

publish​

Publish the given message (json) on the names topic of type. Will advertise the topic if not yet advertised.

Parameters​
  • topic
  • type
  • message
  • latching (optional, default true)

subscribe​

Subscribe to the named topic of the named type. Each time a new message is received the provided callback is called. Here options is an optional object: { "throttleMs": throttle-in-milliseconds }.

Parameters​
  • topic
  • type
  • onMessage
  • options (optional, default {})

unsubscribe​

Unsubscribe from topic

Parameters​
  • topic

ROS2​

Small convenient singleton class for interfacing with ROS2, including some auxiliary functions that come in handy in capabilities. Based on rclnodejs.

callService​

Call the given service of the given type with the given body (not required when type is "std_srvs/srv/Empty").

Parameters​
  • serviceName
  • type
  • request (optional, default undefined)

createHeader​

create a std_msgs/Header for the given frame_id and date

Parameters​
  • frame_id (optional, default '')
  • date (optional, default new Date())

getAvailableTypes​

Get all known message, service, and action types, grouped by package.

getServices​

Get list of available services (list of names).

getServiceType​

Get type of a given service.

Parameters​
  • service

getSubscribedTopics​

Get topics that have subscribers

Parameters​
  • type (optional, default undefined)

getTopics​

Get all topic of a given type or all topics ifno type is specified

Parameters​
  • type (optional, default undefined)

getTypeTemplate​

Given a package, category, and type, e.g., 'std_msgs', 'msg', and 'String', return a plain object representing that type, which can be used as a template for creating messages.

Parameters​
  • pkg
  • category
  • type
  • response (optional, default false)

init​

Initialize ROS node. This needs to be called first.

Parameters​
  • suffix (optional, default '')

publish​

Publish the given message (json) on the names topic of type. Will advertise the topic if not yet advertised.

Parameters​
  • topic
  • type
  • message
  • latching (optional, default true)

subscribe​

Subscribe to the named topic of the named type. Each time a new message is received the provided callback is called. For available options see https://robotwebtools.github.io/rclnodejs/docs/0.22.3/Node.html#createSubscription. The default options.qos.reliability is best-effort.

Parameters​
  • topic
  • type
  • onMessage
  • options (optional, default {})

unsubscribe​

Unsubscribe from topic

Parameters​
  • topic

getForVersion​

Get the correct instance for the given ROS version (1 or 2).

Parameters​

  • version