Disable caching in preview server (#6553)

* Useful in case the preview is proxied through a CDN

Only show in developer changelog

newIDE/electron-app/app/ServeFolder.js

@@ -2,6 +2,7 @@ const liveServer = require('live-server');
 const httpsConfiguration = require('./Utils/DevServerHttpsConfiguration.js');
 const { getAvailablePort } = require('./Utils/AvailablePortFinder');
 
+/** @type {import("live-server").LiveServerParams} */
 let currentServerParams = null;
 
 module.exports = {
@@ -27,6 +28,21 @@ module.exports = {
           // the hot-reloading built into the game engine is what should
           // be used - and the user can still reload manually on its browser.
           watch: [],
+          middleware: [
+            // Disable caching, as it can lead to older generated code being served
+            // in case preview files are proxied through a CDN (see 
+            // https://github.com/4ian/GDevelop/pull/6553 for example)
+            function noCache(_, res, next) {
+              res.setHeader('Surrogate-Control', 'no-store');
+              res.setHeader(
+                'Cache-Control',
+                'no-store, no-cache, must-revalidate, proxy-revalidate'
+              );
+              res.setHeader('Expires', '0');
+
+              next();
+            },
+          ],
         };
         liveServer.start(currentServerParams);
         onDone(null, currentServerParams);

newIDE/electron-app/app/main.js

@@ -295,7 +295,10 @@ app.on('ready', function() {
     log.info('Received event to server folder with options=', options);
 
     serveFolder(options, (err, serverParams) => {
-      event.sender.send('serve-folder-done', err, serverParams);
+      // Using JSON to copy the config strips unserializable properties
+      // (like middleware functions) automatically.
+      const configCopy = JSON.parse(JSON.stringify(serverParams));
+      event.sender.send('serve-folder-done', err, configCopy);
     });
   });