Created question in FIWARE Q/A platform on 20-07-2021 at 12:07
Please, ANSWER this question AT https://stackoverflow.com/questions/68454628/fiware-firos-publish-cmd-vel-from-non-ros-world

Question:
FIWARE FIROS Publish cmd_vel from Non-ROS-World

Description:
Within firos turtlesim example (https://firos.readthedocs.io/en/latest/install/turtlesim-example.html) I'm trying to publish msg on /turtle1/cmd_vel topic from Non-ROS-World trough POST request in order to move the robot.
However I'm not sure how to do that because when I start firos/core.py the list of entities created is:

{"id":".turtle1.pose","type":"turtlesim%2FPose","angular_velocity":{"type":"number","value":0,"metadata":{"dataType":

}},"linear_velocity":{"type":"number","value":0,"metadata":{"dataType":

}},"theta":{"type":"number","value":0,"metadata":{"dataType":

}},"x":{"type":"number","value":5.544444561,"metadata":{"dataType":

}},"y":{"type":"number","value":5.544444561,"metadata":{"dataType":{"type":"dataType","value":"float32"}}}}

And the list of subscriptions is:

{"id":"XXXX","expires":"2021-06-09T22:10:17.000Z","status":"active","subject":{"entities":[

],"condition":{"attrs":[]}},"notification":{"attrs":["linear","angular"],"onlyChangedAttrs":false,"attrsFormat":"normalized","http":

}}

None entity with .turtle1.cmd_vel id is created, so that I don't know how to update for example linear attr. Do I have to create .turtle1.cmd_vel entity manually first and update attr after? I tried it:
curl -iX POST \
'http://localhost:1026/v2/entities' \
-H 'Content-Type: application/json' \
-d '
{
"id": ".turtle1.cmd_vel",
"type": "geometry_msgs%2FTwist",
"linear": {
"type": "float64",
"value":

},
"angular": {
"type": "float64",
"value":

}
}'

but I got errors.