Solar-Wrapper

A Node.js proxy server that bridges an oneM2M IoT platform (Mobius / oM2M) and a browser-based monitoring dashboard for a solar + battery + load energy system.

Status: deployed against real solar hardware in October 2019. This repository is preserved as a portfolio snapshot of that deployment — it is not actively maintained.

What it does

The wrapper sits in the middle of an IoT data path:

                +--------------------+          +--------------------+          +--------------------+
   Sensors ---> |  oneM2M server     |  HTTP    |  Solar-Wrapper     |  WS      |  Dashboard (web)   |
   & inverter   |  (Mobius / oM2M)   | -------> |  (this repo)       | ------>  |                    |
                |                    | <------- |                    | <------- |                    |
                +--------------------+   HTTP   +--------------------+   WS     +--------------------+
                                        PUT                                   commands

• Inbound. oneM2M pushes notification envelopes (m2m:sgn → m2m:nev → m2m:rep → m2m:fcnt) to /solar, /battery, and /load whenever a subscribed value changes. The wrapper unpacks the nested payload and re-emits one socket.io event per measurement to the dashboard.
• Outbound. The dashboard POSTs charge / discharge commands to /charging and /discharging. The wrapper wraps them in the oneM2M m2m:fcnt format and PUTs them back into the oneM2M container so the physical controller can act on them.

Architecture

Single Node.js process exposing two I/O surfaces on two ports:

Port	Protocol	Direction	Purpose
19998	HTTP (Express)	oneM2M → wrapper, dashboard → wrapper	Receive notifications and commands
19997	Socket.io (WS)	wrapper → dashboard	Push parsed measurements to the browser

Internally, a single generic worker (getRequestedData.doWork) handles all three device families. Per-family behaviour is expressed as two index-aligned arrays — for example, for solar:

solarEntityName = ["current", "voltage", "power", "daily", "monthly", "annual", "total"];
solarEventName  = ["solarCurrent", "solarVoltage", "solarPower", "solarDaily", "solarMonthly", "solarAnnual", "solarTotal"];

The worker walks entityName[i], reads that field out of the oneM2M payload, and emits it under eventName[i] on the socket. Adding a measurement is a matter of appending the same index to both arrays. /battery adds extra guards to ignore charge / discharge status and connection-check notifications so that only real measurements are forwarded.

Workflow

1. oneM2M sensors publish values to their respective containers.
2. oneM2M notifies subscribers by POSTing the change envelope to Solar-Wrapper.
3. The wrapper acknowledges with 200 Successful, then extracts every field named in the entity list.
4. Each field is emitted as a socket.io event; the dashboard subscribes and re-renders.
5. When an operator clicks a control on the dashboard, the dashboard POSTs { "command": "0" | "1" } to /charging or /discharging.
6. The wrapper PUTs the equivalent m2m:fcnt payload to the oneM2M container, and the physical controller reacts.

Every step is mirrored to ./log/logging.log via log4js and to stdout with a millisecond-precision timestamp.

Why this exists (the niche)

oneM2M is a standards-body IoT protocol used heavily in Korean research deployments (Mobius is KETI's reference implementation of it). Its notification envelopes are deeply nested (m2m:sgn.m2m:nev.m2m:rep.m2m:fcnt.<field>) and are not something a typical web dashboard wants to parse directly. This wrapper is the thin adapter that lets a plain socket.io dashboard talk to a oneM2M backend without either side having to know about the other's shape — the dashboard sees named measurement events, and the oneM2M server sees a well-behaved subscriber and command source.

Running it

node server_express.js

Note: the npm start script in package.json points at server.js, which does not exist in this snapshot — invoke the file directly.

Configuration lives in config/app_config.js. In this snapshot only port is actually read at runtime; the target oneM2M URL for command PUTs is hard-coded to the LAN address of the 2019 test bench (http://192.168.0.21:8080/~/in-cse/fcnt-548319540). The log/ directory must exist for log4js to initialise.

Stack

• Express 4 — HTTP surface
• socket.io 2 — push channel to the dashboard
• request / axios — outbound oneM2M PUTs
• log4js — file + console logging
• body-parser, cors — middleware

Repository layout

server_express.js     Main entry point — HTTP + socket.io server
server_express2.js    Earlier partial draft, kept for history — not used
config/app_config.js  Port, Mobius URLs, oneM2M header values
log/                  log4js output (gitignored)