chore: import upstream snapshot with attribution

api/server/utils/staticCache.js

@@ -0,0 +1,65 @@
+const path = require('path');
+const express = require('express');
+const expressStaticGzip = require('express-static-gzip');
+
+const oneDayInSeconds = 24 * 60 * 60;
+
+const sMaxAge = process.env.STATIC_CACHE_S_MAX_AGE || oneDayInSeconds;
+const maxAge = process.env.STATIC_CACHE_MAX_AGE || oneDayInSeconds * 2;
+const isEnabled = (value) => value === true || String(value).toLowerCase() === 'true';
+
+/**
+ * Creates an Express static middleware with optional precompressed asset serving and configurable caching
+ *
+ * @param {string} staticPath - The file system path to serve static files from
+ * @param {Object} [options={}] - Configuration options
+ * @param {boolean} [options.noCache=false] - If true, disables caching entirely for all files
+ * @param {boolean} [options.skipGzipScan=false] - If true, skips expressStaticGzip middleware
+ * @returns {ReturnType<expressStaticGzip>|ReturnType<express.static>} Express middleware function for serving static files
+ */
+function staticCache(staticPath, options = {}) {
+  const { noCache = false, skipGzipScan = false } = options;
+  const enableBrotli = isEnabled(process.env.ENABLE_STATIC_ASSET_BROTLI);
+
+  const setHeaders = (res, filePath) => {
+    if (process.env.NODE_ENV?.toLowerCase() !== 'production') {
+      return;
+    }
+    if (noCache) {
+      res.setHeader('Cache-Control', 'no-store, no-cache, must-revalidate');
+      return;
+    }
+    if (filePath && filePath.includes('/dist/images/')) {
+      return;
+    }
+    const fileName = filePath ? path.basename(filePath) : '';
+
+    if (
+      fileName === 'index.html' ||
+      fileName.endsWith('.webmanifest') ||
+      fileName === 'manifest.json' ||
+      fileName === 'sw.js' ||
+      fileName === 'sw-heal.js'
+    ) {
+      res.setHeader('Cache-Control', 'no-store, no-cache, must-revalidate');
+    } else {
+      res.setHeader('Cache-Control', `public, max-age=${maxAge}, s-maxage=${sMaxAge}`);
+    }
+  };
+
+  if (skipGzipScan) {
+    return express.static(staticPath, {
+      setHeaders,
+      index: false,
+    });
+  } else {
+    return expressStaticGzip(staticPath, {
+      enableBrotli,
+      orderPreference: enableBrotli ? ['br', 'gz'] : ['gz'],
+      setHeaders,
+      index: false,
+    });
+  }
+}
+
+module.exports = staticCache;