Implement texture proxy and caching mechanism: add endpoint for fetching textures with cache handling

web/server/server.js

@@ -2,12 +2,18 @@ import express from 'express';
 import { WebSocketServer } from 'ws';
 import cors from 'cors';
 import { createServer } from 'http';
+import fs from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
 import {
   loadFullState, saveFullState, recordItemHistory,
   saveItems, saveFurnaces, saveAlerts, saveState,
   getHistory, getHistorySummary, closeDb, flushPendingSave,
 } from './db.js';
 
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const app = express();
 const PORT = process.env.PORT || 3001;
 const HOST = process.env.HOST || '0.0.0.0';
@@ -72,6 +78,97 @@ function pushCommandToBridge(command) {
 // ========== HTTP Server ==========
 const server = createServer(app);
 
+// ========== Texture Proxy / Cache ==========
+const TEXTURE_CACHE_DIR = process.env.TEXTURE_CACHE_DIR || path.join('/data', 'texture-cache');
+const NEGATIVE_CACHE_TTL = 7 * 24 * 60 * 60 * 1000; // 7 days for 404s
+
+// Upstream CDN mapping
+const TEXTURE_UPSTREAMS = {
+  minecraft: 'https://cdn.jsdelivr.net/gh/InventivetalentDev/minecraft-assets@1.21.4/assets/minecraft/textures',
+  computercraft: 'https://raw.githubusercontent.com/cc-tweaked/CC-Tweaked/mc-1.20.x/projects/common/src/main/resources/assets/computercraft/textures',
+  create: 'https://raw.githubusercontent.com/Creators-of-Create/Create/mc1.20.1/dev/src/main/resources/assets/create/textures',
+};
+
+// Ensure cache directory exists
+fs.mkdirSync(TEXTURE_CACHE_DIR, { recursive: true });
+
+app.get('/api/texture/:namespace/*', async (req, res) => {
+  const { namespace } = req.params;
+  const texturePath = req.params[0]; // e.g. "item/diamond.png"
+
+  const upstream = TEXTURE_UPSTREAMS[namespace];
+  if (!upstream) {
+    return res.status(404).send('Unknown namespace');
+  }
+
+  // Sanitize path to prevent directory traversal
+  const safePath = path.normalize(texturePath).replace(/^(\.\.(\/|\\|$))+/, '');
+  if (safePath.includes('..')) {
+    return res.status(400).send('Invalid path');
+  }
+
+  const cacheFile = path.join(TEXTURE_CACHE_DIR, namespace, safePath);
+  const cacheDir = path.dirname(cacheFile);
+  const missFile = cacheFile + '.miss';
+
+  // Check positive cache
+  try {
+    if (fs.existsSync(cacheFile)) {
+      res.set('Content-Type', 'image/png');
+      res.set('Cache-Control', 'public, max-age=604800'); // 7 days
+      res.set('X-Texture-Cache', 'HIT');
+      return res.sendFile(cacheFile);
+    }
+  } catch (_) { /* proceed to fetch */ }
+
+  // Check negative cache (cached 404s)
+  try {
+    if (fs.existsSync(missFile)) {
+      const stat = fs.statSync(missFile);
+      const age = Date.now() - stat.mtimeMs;
+      if (age < NEGATIVE_CACHE_TTL) {
+        res.set('X-Texture-Cache', 'MISS-HIT');
+        return res.status(404).send('Not found (cached)');
+      }
+      // Expired negative cache, remove it
+      fs.unlinkSync(missFile);
+    }
+  } catch (_) { /* proceed to fetch */ }
+
+  // Fetch from upstream
+  const upstreamUrl = `${upstream}/${safePath}`;
+  try {
+    const response = await fetch(upstreamUrl);
+
+    if (!response.ok) {
+      // Cache the 404 so we don't keep hitting upstream
+      try {
+        fs.mkdirSync(cacheDir, { recursive: true });
+        fs.writeFileSync(missFile, `${response.status}`);
+      } catch (_) { /* ignore cache write errors */ }
+      res.set('X-Texture-Cache', 'UPSTREAM-MISS');
+      return res.status(404).send('Not found');
+    }
+
+    // Save to disk cache
+    const buffer = Buffer.from(await response.arrayBuffer());
+    try {
+      fs.mkdirSync(cacheDir, { recursive: true });
+      fs.writeFileSync(cacheFile, buffer);
+      // Remove any stale negative cache
+      if (fs.existsSync(missFile)) fs.unlinkSync(missFile);
+    } catch (_) { /* ignore cache write errors */ }
+
+    res.set('Content-Type', response.headers.get('content-type') || 'image/png');
+    res.set('Cache-Control', 'public, max-age=604800');
+    res.set('X-Texture-Cache', 'UPSTREAM-HIT');
+    return res.send(buffer);
+  } catch (err) {
+    console.error(`[Texture Proxy] Error fetching ${upstreamUrl}:`, err.message);
+    return res.status(502).send('Upstream error');
+  }
+});
+
 // Health check
 app.get('/api/health', (req, res) => {
   res.json({