Feature: Add APC UPS widget (#4840)

Co-authored-by: shamoon <4887959+shamoon@users.noreply.github.com>

src/widgets/apcups/proxy.js

@@ -0,0 +1,112 @@
+import net from "node:net";
+import { Buffer } from "node:buffer";
+
+import getServiceWidget from "utils/config/service-helpers";
+import createLogger from "utils/logger";
+
+const logger = createLogger("apcupsProxyHandler");
+
+function parseResponse(buffer) {
+  let ptr = 0;
+  const output = [];
+  while (ptr < buffer.length) {
+    const lineLen = buffer.readUInt16BE(ptr);
+    const asciiData = buffer.toString("ascii", ptr + 2, lineLen + ptr + 2);
+    output.push(asciiData);
+    ptr += 2 + lineLen;
+  }
+
+  return output;
+}
+
+function statusAsJSON(statusOutput) {
+  return statusOutput?.reduce((output, line) => {
+    if (!line || line.startsWith("END APC")) return output;
+    const [key, value] = line.trim().split(":");
+    const newOutput = { ...output };
+    newOutput[key.trim()] = value?.trim();
+    return newOutput;
+  }, {});
+}
+
+async function getStatus(host = "127.0.0.1", port = 3551) {
+  return new Promise((resolve, reject) => {
+    const socket = new net.Socket();
+    socket.setTimeout(5000);
+    socket.connect({ host, port });
+
+    const response = [];
+
+    socket.on("connect", () => {
+      const CMD = "status";
+      logger.debug(`Connecting to ${host}:${port}`);
+      const buffer = Buffer.alloc(CMD.length + 2);
+      buffer.writeUInt16BE(CMD.length, 0);
+      buffer.write(CMD, 2);
+      socket.write(buffer);
+    });
+
+    socket.on("data", (data) => {
+      response.push(data);
+
+      if (data.readUInt16BE(data.length - 2) === 0) {
+        try {
+          const buffer = Buffer.concat(response);
+          const output = parseResponse(buffer);
+          resolve(output);
+        } catch (e) {
+          reject(e);
+        }
+        socket.end();
+      }
+    });
+
+    socket.on("error", (err) => {
+      socket.destroy();
+      reject(err);
+    });
+    socket.on("timeout", () => {
+      socket.destroy();
+      reject(new Error("socket timeout"));
+    });
+    socket.on("end", () => {
+      logger.debug("socket end");
+    });
+    socket.on("close", () => {
+      logger.debug("socket closed");
+    });
+  });
+}
+
+export default async function apcupsProxyHandler(req, res) {
+  const { group, service, index } = req.query;
+
+  if (!group || !service) {
+    logger.debug("Invalid or missing service '%s' or group '%s'", service, group);
+    return res.status(400).json({ error: "Invalid proxy service type" });
+  }
+
+  const widget = await getServiceWidget(group, service, index);
+  if (!widget) {
+    logger.debug("Invalid or missing widget for service '%s' in group '%s'", service, group);
+    return res.status(400).json({ error: "Invalid proxy service type" });
+  }
+
+  const url = new URL(widget.url);
+  const data = {};
+
+  try {
+    const statusData = await getStatus(url.hostname, url.port);
+    const jsonData = statusAsJSON(statusData);
+
+    data.status = jsonData.STATUS;
+    data.load = jsonData.LOADPCT;
+    data.bcharge = jsonData.BCHARGE;
+    data.timeleft = jsonData.TIMELEFT;
+  } catch (e) {
+    logger.error(e);
+    return res.status(500).json({ error: e.message });
+  }
+
+  return res.status(200).send(data);
+}