Merge pull request #122 from SpareCores/cache-headers-middleware

move cache headers to middleware and fix giscuss.css CORS

server.ts

@@ -1,3 +1,4 @@
+import os from 'os';
 import { APP_BASE_HREF } from '@angular/common';
 import { CommonEngine } from '@angular/ssr';
 import express from 'express';
@@ -9,11 +10,15 @@ import { REQUEST, RESPONSE } from './src/express.tokens';
 // The Express app is exported so that it can be used by serverless Functions.
 export function app(): express.Express {
   const server = express();
+  const loggerData: Record<string, any> = {};
 
   // access log
   server.use((req, res, next) => {
+    loggerData.startTime = new Date();
+    loggerData.resourceUsage = process.resourceUsage();
     const { protocol, originalUrl, ip, headers } = req;
     const log = {
+      event: "request",
       method: req.method,
       path: originalUrl,
       userAgent: headers['user-agent'],
@@ -35,30 +40,84 @@ export function app(): express.Express {
   server.set('view engine', 'html');
   server.set('views', browserDistFolder);
 
-  // Serve static files
-  server.get('*.*', express.static(browserDistFolder, {
-    setHeaders: (res, path) => {
-      const generatedJsPattern = /-[A-Z0-9]+\.(js|css|woff2)$/;
-      if (generatedJsPattern.test(path)) {
-        // generated files with hashed filenames can be cached forever
-        res.setHeader('Cache-Control', 'public, max-age=31536000, immutable');
-      } else {
-        // default to cache for 1 hour
-        res.setHeader('Cache-Control', 'public, max-age=3600');
-      }
+  // return early with stats
+  server.get('/healthcheck', (req, res) => {
+    const stats = {
+      status: 'healthy',
+      host: os.hostname(),
+      memory: {
+        maxRss: loggerData.resourceUsage.maxRSS,
+      },
+      cpu: {
+        user: loggerData.resourceUsage.userCPUTime,
+        sys: loggerData.resourceUsage.systemCPUTime,
+      },
+      uptime: process.uptime().toFixed(2)
+    };
+    res.status(200).json(stats);
+  });
+
+  // redirect from www
+  server.use((req, res, next) => {
+    const host = req.hostname;
+    if (host.startsWith('www.')) {
+      const newHost = host.substring(4);
+      return res.redirect(301, `${req.protocol}://${newHost}${req.originalUrl}`);
     }
-  }));
+    next();
+  });
+
+  // cache headers for the static files
+  server.use((req, res, next) => {
+    const generatedJsPattern = /-[A-Z0-9]+\.(js|css|woff2)$/;
+    if (req.path === '/assets/giscus.css') {
+      // CORS for hosted file referencing external resources
+      res.setHeader('Access-Control-Allow-Origin', 'https://giscus.app');
+      res.setHeader('Access-Control-Allow-Methods', 'OPTIONS,GET');
+      res.setHeader('Cache-Control', 'public, max-age=86400');
+    } else if (generatedJsPattern.test(req.path)) {
+      // Generated files with hashed filenames can be cached forever
+      res.setHeader('Cache-Control', 'public, max-age=31536000, immutable');
+    } else {
+      // Default cache for 1 hour
+      res.setHeader('Cache-Control', 'public, max-age=3600');
+    }
+    next();
+  });
+
+  // Serve static files
+  server.get('*.*', express.static(browserDistFolder));
 
   // Cache dynamic content for 10 mins
   server.use((req, res, next) => {
     res.setHeader('Cache-Control', 'public, max-age=600');
     next();
   });
 
+  // log time to generate dynamic content
+  server.use((req, res, next) => {
+    res.on("close", () => {
+      const currentResourceUsage = process.resourceUsage();
+      const currentTime = new Date();
+      const elapsedTime = (currentTime.getTime() - loggerData.startTime.getTime()) / 1e3;
+      const userTime = (currentResourceUsage.userCPUTime - loggerData.resourceUsage.userCPUTime) / 1e6;
+      const sysTime = (currentResourceUsage.systemCPUTime - loggerData.resourceUsage.systemCPUTime) / 1e6;
+      const log = {
+        event: "response",
+        path: req.originalUrl,
+        real: elapsedTime.toFixed(2),
+        user: userTime.toFixed(2),
+        sys: sysTime.toFixed(2),
+        wait: (elapsedTime - userTime - sysTime).toFixed(2),
+      }
+      console.log(JSON.stringify(log));
+    })
+    next()
+  })
+
   // All regular routes use the Angular engine
   server.get('*', (req, res, next) => {
     const { protocol, originalUrl, baseUrl, headers } = req;
-
     commonEngine
       .render({
         bootstrap,