feat: Initial code drop

lib/ipfs.js

@@ -0,0 +1,113 @@
+const NodeCache = require('node-cache');
+const config = require('../config');
+const { IPFS_GATEWAY, CACHE_ENABLED, CACHE_TTL_SECONDS } = config;
+
+// Setup cache
+const cache = new NodeCache({ 
+  stdTTL: CACHE_TTL_SECONDS,
+  checkperiod: CACHE_TTL_SECONDS * 0.2,
+});
+
+// MIME type mapping helper
+const mimeTypes = {
+  '.html': 'text/html',
+  '.css': 'text/css',
+  '.js': 'application/javascript',
+  '.json': 'application/json',
+  '.png': 'image/png',
+  '.jpg': 'image/jpeg',
+  '.jpeg': 'image/jpeg',
+  '.gif': 'image/gif',
+  '.svg': 'image/svg+xml',
+  '.pdf': 'application/pdf',
+  '.txt': 'text/plain'
+};
+
+/**
+ * Fetch content from IPFS by CID and path
+ * @param {string} cid - IPFS Content Identifier
+ * @param {string} path - Optional path within the CID
+ * @returns {Promise<{data: Buffer, mimeType: string}|null>} - Content and MIME type or null
+ */
+async function fetchFromIpfs(cid, path = '') {
+  const contentPath = path ? `${cid}/${path}` : cid;
+  
+  // Check cache first
+  if (CACHE_ENABLED) {
+    const cachedContent = cache.get(`ipfs:${contentPath}`);
+    if (cachedContent) {
+      console.log(`Cache hit for IPFS content: ${contentPath}`);
+      return cachedContent;
+    }
+  }
+  
+  try {
+    // Use the HTTP gateway directly instead of the IPFS client
+    const result = await fetchViaGateway(cid, path);
+    
+    if (!result) {
+      return null;
+    }
+    
+    // Determine MIME type if not set
+    if (!result.mimeType) {
+      result.mimeType = getMimeType(path);
+    }
+    
+    // Cache the result
+    if (CACHE_ENABLED) {
+      cache.set(`ipfs:${contentPath}`, result);
+    }
+    
+    return result;
+  } catch (error) {
+    console.error(`Error fetching ${contentPath} from IPFS:`, error);
+    return null;
+  }
+}
+
+/**
+ * Fetch content via IPFS HTTP gateway
+ * @param {string} cid - IPFS Content Identifier
+ * @param {string} path - Path within the CID
+ * @returns {Promise<{data: Buffer, mimeType: string}|null>} - Content and MIME type or null
+ */
+async function fetchViaGateway(cid, path) {
+  try {
+    const url = new URL(`${IPFS_GATEWAY}/ipfs/${cid}${path ? '/' + path : ''}`);
+    console.log(`Fetching from IPFS gateway: ${url}`);
+    
+    const response = await fetch(url);
+    
+    if (!response.ok) {
+      console.error(`Gateway returned ${response.status} for ${url}`);
+      return null;
+    }
+    
+    const data = Buffer.from(await response.arrayBuffer());
+    const mimeType = response.headers.get('content-type');
+    
+    return { data, mimeType };
+  } catch (error) {
+    console.error('Gateway fetch error:', error);
+    return null;
+  }
+}
+
+/**
+ * Determine MIME type from file path
+ * @param {string} path - File path
+ * @returns {string} - MIME type or default
+ */
+function getMimeType(path) {
+  if (!path) return 'application/octet-stream';
+  
+  const extension = path.split('.').pop();
+  if (!extension) return 'application/octet-stream';
+  
+  return mimeTypes['.' + extension] || 'application/octet-stream';
+}
+
+module.exports = {
+  fetchFromIpfs
+};