Switch from http polling to data push via websockets

3 files changed, 25 insertions, 189 deletions

diff --git a/routes/energy-usage.js b/routes/energy-usage.js
deleted file mode 100644
index eb21eb9..0000000
--- a/routes/energy-usage.js
+++ /dev/null
@@ -1,166 +0,0 @@
-const express = require('express');
-const router = express.Router();
-
-const deviceManager = require('../services/device-manager');
-const moment = require('moment');
-
-router.get('/:deviceId/realtime', function(req, res, next) {
-
-  let deviceId = req.params.deviceId;
-
-  let realtimeUsage = {};
-  // TODO - cache results with a short TTL so we don't hammer the plug if multiple clients are requesting data
-  deviceManager.getDevice(deviceId).emeter.getRealtime().then(response => {
-
-    // Voltage seems to be reported as its peak to peak value, not RMS.
-    // Show the RMS value since thats what would you expect to see.
-    // i.e. 220v not 310v (in the U.K)
-    response.voltage = response.voltage / Math.sqrt(2);
-
-    res.json(response);
-  });
-
-});
-
-router.get('/:deviceId/day-stats', function(req, res, next) {
-  
-  let deviceId = req.params.deviceId;
-
-  // Get last x days
-  let totalDaysRequired = 30; // TODO currently only works for up to 2 months spans
-  let currentMoment = moment();
-  let previousMoment = moment().subtract(totalDaysRequired, 'days');
-
-  // Month + 1 as the API months are index 1 based.
-  deviceManager.getDevice(deviceId).emeter.getDayStats(currentMoment.year(), currentMoment.month() +1).then(currentPeriodStats => {
-
-    // Check if we also need the previous month to meet the required total number of samples
-    if(currentMoment.month() !== previousMoment.month()) {
-      
-      // Get previous month. This currently wont work if the previousMoment is more than 1 month before the currentMoment (see above)
-      deviceManager.getDevice(deviceId).emeter.getDayStats(previousMoment.year(), previousMoment.month() +1).then(previousPeriodStats => {
-
-        let currentMonthStats = fillMissingDays(currentPeriodStats, currentMoment);
-        let previousMonthStats = fillMissingDays(previousPeriodStats, previousMoment);
-        let combinedStats = previousMonthStats.concat(currentMonthStats);
-
-        res.json(trimStatResults(combinedStats, totalDaysRequired));
-
-      });
-    }
-    else {
-      let dayStats = fillMissingDays(currentPeriodStats, currentMoment);
-  
-      res.json(trimStatResults(dayStats, totalDaysRequired));
-    }
-
-  });
-
-});
-
-router.get('/:deviceId/month-stats', function(req, res, next) {
-  let deviceId = req.params.deviceId;
-
-  // Get last x months
-  let totalMonthsRequired = 12; // TODO currently only works for up to 14 month (2 year) spans
-  let currentMoment = moment();
-  let previousMoment = moment().subtract(totalMonthsRequired, 'months');
-
-  deviceManager.getDevice(deviceId).emeter.getMonthStats(currentMoment.year()).then(currentPeriodStats => {
-
-    // Check if we also need the previous year to meet the required total number of samples
-    if(currentMoment.month() + 1 < totalMonthsRequired) {
-      
-      // Get previous year (assuming the totalMonthsRequired limit described above).
-      deviceManager.getDevice(deviceId).emeter.getMonthStats(previousMoment.year()).then(previousPeriodStats => {
-
-        let currentYearStats = fillMissingMonths(currentPeriodStats, currentMoment);
-        let previousYearStats = fillMissingMonths(previousPeriodStats, previousMoment);
-        let combinedStats = previousYearStats.concat(currentYearStats);
-
-        res.json(trimStatResults(combinedStats, totalMonthsRequired));
-
-      });
-    }
-    else {
-      let monthStats = fillMissingMonths(currentPeriodStats, currentMoment);
-
-      res.json(trimStatResults(monthStats, totalMonthsRequired));
-    }
-
-  });
-
-});
-
-function fillMissingDays(sparseDayStats, statsMoment) {
-  let denseDayStats = [];
-
-  let totalDays;
-  // If these stats are for the current month, fill up to the current day of the month
-  // Otherwise fill the whole month
-  if(moment().month() === statsMoment.month()) {
-    totalDays = statsMoment.date();
-  }
-  else {
-    totalDays = statsMoment.daysInMonth();
-  }
-
-  Array.from({length: totalDays}, (x,i) => i + 1).forEach(d => {
-
-    let stat = sparseDayStats.day_list.find(i => i.day === d);
-
-    if(stat === undefined) {
-      denseDayStats.push({
-        year: statsMoment.year(),
-        month: statsMoment.month() +1,
-        day: d,
-        energy: 0
-      })
-    }
-    else {
-      denseDayStats.push(stat);
-    }
-
-  });
-
-  return denseDayStats;
-}
-
-function fillMissingMonths(sparseMonthStats, statsMoment) {
-  let denseMonthStats = [];
-
-  let maxMonths;
-  // Dont fill in months which exist in the future
-  if(statsMoment.year() === moment().year()) {
-    maxMonths = moment().month() + 1; // API months are 1 based
-  }
-  else {
-    maxMonths = 12;
-  }
-
-  // Fill in any missing months up to the max amount
-  Array.from({length: maxMonths}, (x,i) => i + 1).forEach(m => {
-
-    let stat = sparseMonthStats.month_list.find(i => i.month === m);
-
-    if(stat === undefined) {
-      denseMonthStats.push({
-        year: statsMoment.year(),
-        month: m,
-        energy: 0
-      })
-    }
-    else {
-      denseMonthStats.push(stat);
-    }
-
-  });
-
-  return denseMonthStats;
-}
-
-function trimStatResults(stats, maxSamples) {
-  return stats.splice(stats.length - maxSamples, stats.length);
-}
-
-module.exports = router;
\ No newline at end of file
diff --git a/routes/power-state.js b/routes/power-state.js
deleted file mode 100644
index 6333863..0000000
--- a/routes/power-state.js
+++ /dev/null
@@ -1,23 +0,0 @@
-const express = require('express');
-const router = express.Router();
-
-const deviceManager = require('../services/device-manager');
-const moment = require('moment');
-
-router.get('/:deviceId', function(req, res, next) {
-
-  let deviceId = req.params.deviceId;
-
-  deviceManager.getDevice(deviceId).getSysInfo().then(response => {
-
-    let powerState = {
-      isOn: (response.relay_state === 1),
-      uptime: response.on_time
-    };
-
-    res.json(powerState);
-  });
-
-});
-
-module.exports = router;
\ No newline at end of file
diff --git a/routes/ws.js b/routes/ws.js
new file mode 100644
index 0000000..dc22df2
--- /dev/null
+++ b/routes/ws.js
@@ -0,0 +1,25 @@
+const express = require('express');
+const router = express.Router();
+
+const deviceManager = require('../services/device-manager');
+const dataFetcher = require('../services/data-fetcher');
+const dataBroadcaster = require('../services/data-broadcaster');
+
+router.ws('/', function(ws, req) {
+
+  ws.on('message', msg => {
+
+    // Latest data is always pushed out to clients, but clients can also request cached data at any time.
+    if(msg === 'getCachedData') {
+      let cachedData = dataFetcher.getCachedData();
+
+      ws.send(dataBroadcaster.generatePayload('realtimeUsage', cachedData.realtimeUsage));
+      ws.send(dataBroadcaster.generatePayload('dailyUsage', cachedData.dailyUsage));
+      ws.send(dataBroadcaster.generatePayload('monthlyUsage', cachedData.monthlyUsage));
+      ws.send(dataBroadcaster.generatePayload('powerState', cachedData.powerState));
+    }
+  });
+
+});
+
+module.exports = router;