Add server-only webhook plugin with deduplication

lib/plugins/index.js

@@ -53,6 +53,7 @@ function init (ctx) {
     , require('./dbsize')(ctx)
   ];
 
+  /*
   var serverDefaultPlugins = [
     require('./bgnow')(ctx)
     , require('./rawbg')(ctx)
@@ -77,13 +78,59 @@ function init (ctx) {
     , require('./basalprofile')(ctx)
     , require('./dbsize')(ctx)
     , require('./runtimestate')(ctx)
+    , require('./webhook')(ctx) // NEW: Webhook plugin to send SGV updates to a local server address (e.g. Raspberry Pi)
   ];
+*/
+
+  function getServerDefaultPlugins () {
+    var plugins = [
+      require('./bgnow')(ctx)
+      , require('./rawbg')(ctx)
+      , require('./direction')(ctx)
+      , require('./upbat')(ctx)
+      , require('./ar2')(ctx)
+      , require('./simplealarms')(ctx)
+      , require('./errorcodes')(ctx)
+      , require('./iob')(ctx)
+      , require('./cob')(ctx)
+      , require('./pump')(ctx)
+      , require('./openaps')(ctx)
+      , require('./xdripjs')(ctx)
+      , require('./loop')(ctx)
+      , require('./boluswizardpreview')(ctx)
+      , require('./cannulaage')(ctx)
+      , require('./sensorage')(ctx)
+      , require('./insulinage')(ctx)
+      , require('./batteryage')(ctx)
+      , require('./treatmentnotify')(ctx)
+      , require('./timeago')(ctx)
+      , require('./basalprofile')(ctx)
+      , require('./dbsize')(ctx)
+      , require('./runtimestate')(ctx)
+    ];
+
+  // Only load webhook plugin in Node/server (avoid webpack/browser bundling).
+  // NOTE: Use eval('require') so webpack won't statically include './webhook' in the client bundle.
+  if (typeof process !== 'undefined' && process.versions && process.versions.node) {
+      var req = eval('require');
+      plugins.push(req('./webhook')(ctx));
+    }
+
+    return plugins;
+  }
 
+  /*
   plugins.registerServerDefaults = function registerServerDefaults () {
     plugins.register(serverDefaultPlugins);
     return plugins;
   };
+*/
 
+  plugins.registerServerDefaults = function registerServerDefaults () {
+    plugins.register(getServerDefaultPlugins());
+    return plugins;
+  };
+
   plugins.registerClientDefaults = function registerClientDefaults () {
     plugins.register(clientDefaultPlugins);
     return plugins;

lib/plugins/webhook.js

@@ -0,0 +1,171 @@
+'use strict';
+
+// ==================================================================
+// NIGHTSCOUT PLUGIN: Webhook Notifier
+// ==================================================================
+// Sends an HTTP POST webhook to a local server whenever a NEW SGV
+// (glucose) value is available in Nightscout.
+//
+// Configure via environment variables:
+//   WEBHOOK_PROTOCOL  (default: http)
+//   WEBHOOK_HOST      (default: localhost)
+//   WEBHOOK_PORT      (default: 3000)
+//   WEBHOOK_PATH      (default: /nightscout)
+//
+// Example:
+//   WEBHOOK_PROTOCOL=https
+//   WEBHOOK_HOST=192.168.10.5
+//   WEBHOOK_PORT=33333
+//   WEBHOOK_PATH=/nightscout
+//
+// Notes:
+// - This is a server-side Nightscout plugin.
+// - Uses sbx helper methods (lastSGVMgdl / lastSGVMills) for stability.
+// - Deduplicates by timestamp so it triggers once per new SGV.
+// - The SGV present at startup is skipped; only readings ingested after
+//   the process starts will fire a webhook.
+// - lastSentMills is updated only after a successful (2xx) response,
+//   providing at-least-once delivery: a failed request will be retried
+//   on the next checkNotifications cycle.
+// ==================================================================
+
+module.exports = function webhookPlugin() {
+  // ------------------------------------------------------------------
+  // Configuration
+  // ------------------------------------------------------------------
+  const WEBHOOK_PROTOCOL = process.env.WEBHOOK_PROTOCOL || 'http';
+  const WEBHOOK_HOST = process.env.WEBHOOK_HOST || 'localhost';
+  const WEBHOOK_PORT = process.env.WEBHOOK_PORT || '3000';
+  const WEBHOOK_PATH = process.env.WEBHOOK_PATH || '/nightscout';
+  const WEBHOOK_URL = `${WEBHOOK_PROTOCOL}://${WEBHOOK_HOST}:${WEBHOOK_PORT}${WEBHOOK_PATH}`;
+
+  const WEBHOOK_TIMEOUT_MS = 5000;
+
+  const http = require('http');
+  const https = require('https');
+  const url = require('url');
+
+  // mills of the last SGV for which a webhook was successfully delivered.
+  let lastSentMills = null;
+  // mills of a request currently in flight; prevents duplicate concurrent sends.
+  let pendingMills = null;
+  // true after the first checkNotifications call; suppresses the startup SGV.
+  let initialized = false;
+
+  // ------------------------------------------------------------------
+  // Send HTTP/HTTPS POST JSON webhook
+  // Exposed on the returned object so tests can replace it.
+  // ------------------------------------------------------------------
+  function sendWebhook(payload, onSuccess, onFailure) {
+    const parsed = url.parse(WEBHOOK_URL);
+    const protocol = parsed.protocol === 'https:' ? https : http;
+
+    const body = JSON.stringify(payload);
+
+    const options = {
+      hostname: parsed.hostname,
+      port: parsed.port,
+      path: parsed.path,
+      method: 'POST',
+      timeout: WEBHOOK_TIMEOUT_MS,
+      headers: {
+        'Content-Type': 'application/json',
+        'Content-Length': Buffer.byteLength(body)
+      }
+    };
+
+    const req = protocol.request(options, (res) => {
+      // Drain response to avoid socket issues in some Node versions.
+      res.on('data', () => {});
+      res.on('end', () => {
+        if (res.statusCode >= 200 && res.statusCode < 300) {
+          onSuccess();
+        } else {
+          console.warn('[Webhook] Non-2xx response from webhook endpoint:', res.statusCode);
+          onFailure();
+        }
+      });
+    });
+
+    req.on('error', (err) => {
+      console.error('[Webhook] Webhook request failed:', err.message);
+      onFailure();
+    });
+
+    req.on('timeout', () => {
+      console.error('[Webhook] Webhook request timed out after', WEBHOOK_TIMEOUT_MS, 'ms');
+      req.destroy();
+      // onFailure will be called via the 'error' event that destroy() triggers.
+    });
+
+    req.write(body);
+    req.end();
+  }
+
+  // ------------------------------------------------------------------
+  // Nightscout lifecycle hook: called periodically
+  // ------------------------------------------------------------------
+  function checkNotifications(sbx) {
+    if (!sbx) return;
+
+    const mgdl = typeof sbx.lastSGVMgdl === 'function' ? sbx.lastSGVMgdl() : null;
+    const mills = typeof sbx.lastSGVMills === 'function' ? sbx.lastSGVMills() : null;
+
+    if (!mgdl || !mills) return;
+
+    // On first call after startup, record the current SGV as already seen
+    // so we do not fire a webhook for a reading that pre-dates this process.
+    if (!initialized) {
+      lastSentMills = mills;
+      initialized = true;
+      return;
+    }
+
+    // Skip if already successfully delivered or a request is in flight.
+    if (mills === lastSentMills || mills === pendingMills) return;
+
+    pendingMills = mills;
+
+    const payload = {
+      source: 'nightscout',
+      mgdl,
+      mills,
+      iso: new Date(mills).toISOString()
+    };
+
+    // Use plugin.sendWebhook so tests can replace it.
+    plugin.sendWebhook(
+      payload,
+      function onSuccess() {
+        lastSentMills = mills;
+        if (pendingMills === mills) pendingMills = null;
+      },
+      function onFailure() {
+        // Clear pendingMills so the next cycle can retry.
+        if (pendingMills === mills) pendingMills = null;
+      }
+    );
+  }
+
+  // ------------------------------------------------------------------
+  // Plugin metadata
+  // ------------------------------------------------------------------
+  const plugin = {
+    name: 'webhook',
+    label: 'Webhook Notifier',
+    pluginType: 'notification',
+
+    // Called once when the plugin initializes.
+    init: function () {
+      console.log('[Webhook] Enabled. Sending webhooks to:', WEBHOOK_URL);
+    },
+
+    // Replaceable in tests.
+    sendWebhook,
+
+    // Called periodically by Nightscout.
+    checkNotifications
+  };
+
+  return plugin;
+};