rosnodejs 

Install

npm install rosnodejs

Start a node

``js
const rosnodejs = require('rosnodejs');
rosnodejs.initNode('/my_node')
.then(() => {
// do stuff
});
`

Publish/Subscribe

`js
const nh = rosnodejs.nh;
const sub = nh.subscribe('/chatter', 'std_msgs/String', (msg) => {
console.log('Got msg on chatter: %j', msg);
});

const pub = nh.advertise('/chatter', 'std_msgs/String');
pub.publish({ data: "hi" });
`


$3

`js
const nh = rosnodejs.nh;
const sub = nh.subscribe('/chatter', 'std_msgs/String', (msg) => {
console.log('Got msg on chatter: %j', msg);
}, {
transports: ["TCPROS", "UDPROS"], // specify transports, default ["TCPROS"]
dgramSize: 1500 // optional: datagram packet size, default: 1500 bytes
});

const pub = nh.advertise('/chatter', 'std_msgs/String');
pub.publish({ data: "hi" });
`


Services


`js
const service = nh.advertiseService('/add_two_ints', 'beginner_tutorials/AddTwoInts', (req, res) => {
res.sum = req.a + req.b;
return true;
});

const client = nh.serviceClient('/add_two_ints', 'beginner_tutorials/AddTwoInts');
client.call({a: 1, b: 2});
`

Params


`js
nh.setParam('val', 2);
nh.getParam('val')
.then((val) => {
// do stuff
});
`

Generating Messages

Messages can be generated in a number of ways depending on the versions of ROS and Node.js you're using.
- catkin - works in ROS Kinetic and later for Node.js v6+.
`sh
$ catkin_make
OR
$ catkin build
`
- loadAllPackages() - One-time "build" call available through rosnodejs for versions of ROS before Kinetic and Node.js v6+. Should be called separately and in advance of processes attempting to use messages.
`js
const rosnodejs = require('rosnodejs');
rosnodejs.loadAllPackages();
`
- On the fly - all versions of ROS and Node.js 4.5+. When generating on the fly, messages can not be required until the node has initialized.
`js
const rosnodejs = require('rosnodejs');
rosnodejs.initNode('my_node', { onTheFly: true }).then(() => {
const stdMsgs = rosnodejs.require('std_msgs');
...
}
`

| |Pre-Kinetic|Kinetic & Later|
|:---:|:---:|:---:|
|Node.js >= v6|loadAllPackages(), on the fly|catkin, loadAllPackages(), on the fly|
|Node.js < v6|on the fly|on the fly|

Using Messages


`js
const sensorMsgs = rosnodejs.require('sensor_msgs');

const image = new sensorMsgs.msg.Image();
const temperature = new sensorMsgs.msg.Temperature({ temperature: 32 });

const SetCameraInfo = sensorMsgs.srv.SetCameraInfo;
const setRequest = new SetCameraInfo.Request();

// messages can be used when advertising/subscribing
const nh = rosnodejs.nh;
const StringMsg = rosnodejs.require('std_msgs').msg.String;
const sub = nh.subscribe('/chatter', StringMsg, (msg) => { ... });
const pub = nh.advertise('/chatter', StringMsg);

const AddTwoInts = rosnodejs.require('beginner_tutorials').srv.AddTwoInts;
const service = nh.advertiseService('/add_two_ints', AddTwoInts, (req, res) => { ... });
const client = nh.serviceClient('/add_two_ints', AddTwoInts);
`


Actions (Experimental)


`js
const nh = rosnodejs.nh;
const as = new rosnodejs.ActionServer({
nh,
type: 'turtle_actionlib/Shape',
actionServer: '/turtle_shape'
});

as.on('goal', function (goal) {
goal.setAccepted();
});

as.start();

const ac = new rosnodejs.ActionClient({
nh,
type: 'turtle_actionlib/Shape',
actionServer:'/turtle_shape'
});

ac.sendGoal({edges: 3, radius: 1});
`


Run the turtlesim example

Start:

`sh
roscore
rosrun turtlesim turtlesim_node
rosrun turtle_actionlib shape_server
`

Then run
`sh
node src/examples/turtle.js
`

or, if you are running an older version of node:

`sh
npm run compile
node dist/examples/turtle.js
`

Catkin-Like


Checkout rosnodejs_examples for a more catkin-inspired take on using rosnodejs.

Inspired By

rosnodejs` was inspired by other work that you can learn more about here
- roscpp & rospy
- Robots as web services
- ROSBridge
- roslibjs