Get bandwidth data for relay and create ascii chart

controllers/node.js

@@ -1,9 +1,14 @@
-const tor = require('../lib/tor');
+const tor             = require('../lib/tor');
+const bandwidthChart  = require('../lib/bandwidth-chart');
 
 module.exports = (req, res, next) => {
-  tor.node(req.params.id)
-    .then(node => res.render('node.html', {
-      node: node,
+  Promise.all([
+    tor.node(req.params.id),
+    tor.bandwidth(req.params.id)
+  ])
+    .then(data => res.render('node.html', {
+      node: data[0],
+      bandwidth: bandwidthChart(data[1])
     }))
     .catch(error => res.render('node.html', {
       error: error

lib/bandwidth-chart.js

@@ -0,0 +1,52 @@
+const chart = require('ascii-chart');
+
+function pointsFromBandwidthData(values, numPoints) {
+
+  // Define vars
+  const len = values.length;
+  const points = [];
+  let i = 0;
+  let size;
+
+  // Split values into n points
+  if(numPoints < 2) {
+    points.push(values);
+  } else {
+    if(len % numPoints === 0) {
+      size = Math.floor(len / numPoints);
+      while (i < len) {
+        points.push(values.slice(i, i += size));
+      }
+    }
+    while (i < len) {
+      size = Math.ceil((len - i) / numPoints--);
+      points.push(values.slice(i, i += size));
+    }
+  }
+
+  // Return points
+  const result = points
+
+    // Calculate average value of each point
+    .map(point => Math.round(point.reduce((a,b) => a + b) / point.length))
+
+    // Convert bytes to megabytes
+    .map(bytes => Number((bytes / 1000000).toPrecision(3)));
+
+  return result;
+}
+
+module.exports = values => {
+  if(values && values.length) {
+    const points = pointsFromBandwidthData(values, 57);
+    return chart(points, {
+      width: 125,
+      height: 20,
+      padding: 0,
+      pointChar: '*',
+      negativePointChar: '.'
+    });
+  } else {
+    return '';
+  }
+}

lib/tor.js

@@ -21,5 +21,18 @@ module.exports = {
           return details.bridges[0];
         }
       });
+  },
+  bandwidth: id => {
+    return onionoo
+      .bandwidth({ lookup: id })
+      .then(bandwidth => {
+        try {
+          const lastMonth = bandwidth.relays[0].write_history['1_month'];
+          return lastMonth.values.map(value => value * lastMonth.factor)
+        }
+        catch(e) {
+          return [];
+        }
+      });
   }
 };

package.json

@@ -4,6 +4,7 @@
   "description": "Explore the Tor network without JS",
   "main": "index.js",
   "dependencies": {
+    "ascii-chart": "^1.2.0",
     "compression": "^1.6.2",
     "express": "^4.14.0",
     "express-minify": "^0.2.0",