How I can use PUT request via HTTP

[norbert-walter]

https://github.com/SignalK/specification/blob/put-clarification/gitbook-docs/put.md

The documentation means it is possible to use a PUT request via HTTP to send values to SignalK. When I try this then I get only error messages "Cannot PUT". I need a way to send data from PipeDream to SignalK. PipeDrean supports only HTTP requests for forwarding the data. WebSockets I can't use. Witch other way is possible.

[sbender9]

You are misinterpreting that document. PUT is not used for sending values to the server. It is used for doing things like switching on/off a light. Things that will result in some action taking place.

Updating the current value is done with deltas and are normally sent via WebSockets.

The only other way currently is via tcp, but that will only work if security is turned off.

[sbender9]

From that document:

PUT requests are sent to a server to request an action to be taken. For example, a client would use PUT to switch the anchor light on or off, change the heading of the autopilot, or change the current input on a stereo.

Note that this is very different than updating the current state of something. Use a delta update message to report on somethings current value. For example. to report on the current wind speed from a sensor. See Delta Format

[sbender9]

One option would be to use the node-red plugin. There you can use an "http in" node to create an http endpoint to accept deltas.

I can get you an example node-red flow for that.

[sbender9]

Here's a node-red flow that supports POSTing deltas:

[{"id":"21907fdb.1a9ee","type":"signalk-send-delta","z":"66b7c773.3a4ad","name":"","x":600,"y":480,"wires":[]},{"id":"3bfe9946.abdebe","type":"http in","z":"66b7c773.3a4ad","name":"","url":"/delta","method":"post","upload":false,"swaggerDoc":"","x":240,"y":480,"wires":[["21907fdb.1a9ee","8c75c35e.7f0d78"]]},{"id":"8c75c35e.7f0d78","type":"http response","z":"66b7c773.3a4ad","name":"","statusCode":"200","headers":{},"x":580,"y":540,"wires":[]}]

Then you can use:

curl -X POST -H "Authorization: JWT eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6InNiZW5kZXIiLCJpYXQiOjE1NjMyMjk0MDIsImV4cCI6MTU5NDc4NzAwMn0.DE-k3hQf4mAvqR6RYSwSxSV" -H "Content-Type: application/json" -d '{"updates":[{"values":[{"path":"tanks.fuel.0.currentLevel","value":0.5}]}]}' http://localhost:3000/plugins/signalk-node-red/redApi/delta`

Note that you will need an auth token with admin rights if security is on.

[norbert-walter]

Ahhh, ok I understand. The curl sample is great. And how do i do an authorization? How can I switch off the security?

[sbender9]

Note that you need the node-red plugin and flow above deployed for this to work.

To get a token, run the following on your server:

signalk-generate-token -u your_userid -e 1y -s ~/.signalk/security.json

You can disable security by editing ~/.signalk/settings.json. Remove the following section:

"security": {
    "strategy": "./tokensecurity"
  },

[norbert-walter]

Thanks for your support.