Adds lambda function for checking response times

netlify.toml

@@ -65,6 +65,11 @@
   from = "/get-txt"
   to = "/.netlify/functions/get-txt"
   status = 301
+  force = true  
+[[redirects]]
+  from = "/server-status"
+  to = "/.netlify/functions/server-status"
+  status = 301
   force = true
   
 # For router history mode, ensure pages land on index

server/lambda/server-status.js

@@ -0,0 +1,51 @@
+const https = require('https');
+const { performance, PerformanceObserver } = require('perf_hooks');
+
+exports.handler = async function(event, context) {
+  const { url } = event.queryStringParameters;
+
+  if (!url) {
+    return {
+      statusCode: 400,
+      body: JSON.stringify({ message: 'You must provide a URL query parameter!' }),
+    };
+  }
+
+  let dnsLookupTime;
+  let responseCode;
+  let startTime = performance.now();
+
+  const obs = new PerformanceObserver((items) => {
+    dnsLookupTime = items.getEntries()[0].duration;
+    performance.clearMarks();
+  });
+
+  obs.observe({ entryTypes: ['measure'] });
+
+  performance.mark('A');
+
+  return new Promise((resolve) => {
+    https.get(url, (res) => {
+      let data = '';
+      responseCode = res.statusCode;
+      res.on('data', (chunk) => {
+        data += chunk;
+      });
+      res.on('end', () => {
+        performance.mark('B');
+        performance.measure('A to B', 'A', 'B');
+        let responseTime = performance.now() - startTime;
+        obs.disconnect();
+        resolve({
+          statusCode: 200,
+          body: JSON.stringify({ isUp: true, dnsLookupTime, responseTime, responseCode }),
+        });
+      });
+    }).on('error', (e) => {
+      resolve({
+        statusCode: 500,
+        body: JSON.stringify({ isUp: false, error: e.message }),
+      });
+    });
+  });
+};