devicehive-coap-proxy

DeviceHive CoAP-Websockets proxy written in Node.js

How to start

Prerequisite: DeviceHive WebSocket API endpoint.

1. Run CoAP proxy:
   • docker build -t coap-proxy .
   • docker run -e DEBUG=coap-proxy -e PROXY.TARGET=ws://localhost/api/websocket coap-proxy
2. In order to check connectivity run Node.js or Python example. Detailed instructions could be found here.

How it works

• At the first step, issuing Observe request to CoAP proxy will open a new connection and create WebSocket session with the targeted DeviceHive instance;
• If connection was successfully established you'd receive socket id in the response (id of your Websocket session);
• All further requests should be non-Observe and contain 111 header with the specified socket id (from the previous step);
• All further responses will be pushed as a responses to the initial Observe request (which socketID were specified as a value of 111 header. See how it was handled in our examples: Node.js and Python);
• DeviceHive CoAP API is identical to the Websocket one. Please, follow this link to explore detailed description of supported message formats.

Configuration

This proxy has 5 properties to configure, you can override them with environment variables:

1. PROXY.HOST — Proxy server host (default localhost);
2. PROXY.PORT — Proxy server port (default 5683);
3. PROXY.TARGET — DeviceHive WebSocket API endpoint;
4. PROXY.MAX_WS_CONNECTIONS — Maximum number of Websocket connections that proxy is able to establish. After it reaches this value new CoAP clients won't be able to send new Observe requests;
5. DEBUG — To enable debug logging specify coap-proxy;

Or you can mount a volume to the Docker container (config directory).

Establishing Observe connection

In order to establish new connection you'd initiate Observe request. In response you'd receive:

• Response with id property with value of your socket (you should use it for future non-Observe requests in 111 header)
  OR
• error property with error message in case of failure.