refactor: prevent caching html files

apps/server/src/app.ts

@@ -6,9 +6,9 @@ import expressStaticGzip from 'express-static-gzip';
 import http, { type Server } from 'http';
 import cors from 'cors';
 import serverTiming from 'server-timing';
+import { extname, resolve } from 'path';
 
 // import utils
-import { resolve } from 'path';
 import { publicDir, srcDir } from './setup/index.js';
 import { environment, isProduction, updateRouterPrefix } from './externals.js';
 import { ONTIME_VERSION } from './ONTIME_VERSION.js';
@@ -92,10 +92,22 @@ app.use(
   expressStaticGzip(srcDir.clientDir, {
     enableBrotli: true,
     orderPreference: ['br'],
-    // when we build the client all the react subfiles will get a hashed name we can the immutable tag
+    // when we build the client the file names contain a unique hash for the build
+    // this allows us to use the immutable tag
     // as the contents of a build file will never change without also changing its name
-    // so the client dose not need to revalidate the file contetnts with the server
-    serveStatic: { etag: false, lastModified: false, immutable: true, maxAge: '1y' },
+    // meaning that the client does not need to revalidate the contents with the server
+    serveStatic: {
+      etag: false,
+      lastModified: false,
+      immutable: true,
+      maxAge: '1y',
+      setHeaders: (res, file) => {
+        // make sure the HTML files are always revalidated
+        if (extname(file) === '.html') {
+          res.setHeader('Cache-Control', 'public, max-age=0');
+        }
+      },
+    },
   }),
 );