webupdatev1

backend/middleware/imageOptimization.js

@@ -0,0 +1,129 @@
+/**
+ * Image Optimization Middleware
+ * High-performance image serving with streaming and caching
+ */
+const path = require("path");
+const fs = require("fs");
+const fsPromises = require("fs").promises;
+const logger = require("../config/logger");
+
+// Cache for image metadata (not content)
+const metadataCache = new Map();
+const METADATA_CACHE_TTL = 600000; // 10 minutes
+const METADATA_CACHE_MAX = 1000;
+
+// Image mime types
+const MIME_TYPES = {
+  ".jpg": "image/jpeg",
+  ".jpeg": "image/jpeg",
+  ".png": "image/png",
+  ".gif": "image/gif",
+  ".webp": "image/webp",
+  ".svg": "image/svg+xml",
+  ".ico": "image/x-icon",
+  ".avif": "image/avif",
+};
+
+/**
+ * Get or cache image metadata
+ */
+async function getImageMetadata(filePath) {
+  const cached = metadataCache.get(filePath);
+  if (cached && Date.now() - cached.timestamp < METADATA_CACHE_TTL) {
+    return cached.data;
+  }
+
+  try {
+    const stats = await fsPromises.stat(filePath);
+    const metadata = {
+      exists: true,
+      size: stats.size,
+      mtime: stats.mtime.getTime(),
+      etag: `"${stats.size}-${stats.mtime.getTime()}"`,
+      lastModified: stats.mtime.toUTCString(),
+    };
+
+    // LRU eviction
+    if (metadataCache.size >= METADATA_CACHE_MAX) {
+      const firstKey = metadataCache.keys().next().value;
+      metadataCache.delete(firstKey);
+    }
+
+    metadataCache.set(filePath, { data: metadata, timestamp: Date.now() });
+    return metadata;
+  } catch {
+    const notFound = { exists: false };
+    metadataCache.set(filePath, { data: notFound, timestamp: Date.now() });
+    return notFound;
+  }
+}
+
+/**
+ * Serve optimized images with streaming and aggressive caching
+ */
+const imageOptimization = (uploadsDir) => {
+  return async (req, res, next) => {
+    // Only handle image requests
+    const ext = path.extname(req.path).toLowerCase();
+    if (!MIME_TYPES[ext]) {
+      return next();
+    }
+
+    const imagePath = path.join(uploadsDir, req.path.replace("/uploads/", ""));
+
+    // Get cached metadata
+    const metadata = await getImageMetadata(imagePath);
+    if (!metadata.exists) {
+      return next();
+    }
+
+    try {
+      // Check if client has cached version (304 Not Modified)
+      const ifNoneMatch = req.get("if-none-match");
+      const ifModifiedSince = req.get("if-modified-since");
+
+      if (
+        ifNoneMatch === metadata.etag ||
+        ifModifiedSince === metadata.lastModified
+      ) {
+        return res.status(304).end();
+      }
+
+      // Set aggressive caching headers
+      res.set({
+        "Content-Type": MIME_TYPES[ext],
+        "Content-Length": metadata.size,
+        "Cache-Control": "public, max-age=31536000, immutable", // 1 year
+        ETag: metadata.etag,
+        "Last-Modified": metadata.lastModified,
+        Vary: "Accept-Encoding",
+        "X-Content-Type-Options": "nosniff",
+      });
+
+      // Use streaming for efficient memory usage
+      const readStream = fs.createReadStream(imagePath, {
+        highWaterMark: 64 * 1024, // 64KB chunks
+      });
+
+      readStream.on("error", (error) => {
+        logger.error("Image stream error:", {
+          path: imagePath,
+          error: error.message,
+        });
+        if (!res.headersSent) {
+          res.status(500).end();
+        }
+      });
+
+      readStream.pipe(res);
+    } catch (error) {
+      logger.error("Image serve error:", {
+        path: imagePath,
+        error: error.message,
+      });
+      next();
+    }
+  };
+};
+
+module.exports = { imageOptimization };