Fixed vercel serve-handler so that it handles directory junctions and directory symlinks without error

app/server.js

@@ -37,7 +37,21 @@ app.use(express.json());
 
 app.get('/ads.txt', (req, res) => {
   res.setHeader("Content-Type", "text/plain");
-  res.send('google.com, pub-8937572456576531, DIRECT, f08c47fec0942fa0');
+  res.setHeader("Cache-Control", "no-cache");
+  res.send(`google.com, pub-8937572456576531, DIRECT, f08c47fec0942fa0`);
+});
+
+app.get('/robots.txt', (req, res) => {
+  res.setHeader("Content-Type", "text/plain");
+  res.setHeader("Cache-Control", "no-cache");
+  // TODO: Implement Site Map feature and provide sitemap url in robots.txt
+  res.send(
+`User-agent: *
+Allow: /
+
+# TODO: Implement Site Map feature and provide sitemap url in robots.txt
+#sitemap: https://no-moss-3-carbo-landfill-library.online/sitemap.xml`
+  );//end of res.send() for robots.txt
 });
 
 // Search endpoints

app/vercel-serve.js

@@ -4,7 +4,7 @@
 const {promisify} = require('util');
 const path = require('path');
 const {createHash} = require('crypto');
-const {realpath, lstat, createReadStream, readdir} = require('fs');
+const {realpath, readlink, lstat, createReadStream, readdir} = require('fs');
 
 // Packages
 const url = require('fast-url-parser');
@@ -36,7 +36,7 @@ const directoryTemplate = (vals) => {
 };
 const errorTemplate = (vals) => {
   return new Promise((resolve, reject) => {
-    ejs.renderFile("views/error.ejs", { h: helpers, ...vals }, (err, str) => {
+    ejs.renderFile(path.join(__dirname, '..', 'views', 'error.ejs'), { h: helpers, ...vals }, (err, str) => {
     if (err) {
       reject(err);
     } else {
@@ -46,6 +46,19 @@ const errorTemplate = (vals) => {
   });
 };
 
+const isDirectoryOrDirectorySymbolicLink = (path, max_recursion_depth = 10, cb) => {
+	lstat(path, {}, (err, sym_stats) => {
+		if (sym_stats.isSymbolicLink() && max_recursion_depth > 0) {
+			readlink(path, {}, (err, path) => {
+				isDirectoryOrDirectorySymbolicLink(path, max_recursion_depth-1, cb);
+			});
+		}
+		else {
+			cb(err, sym_stats.isDirectory());
+		}
+	});
+};
+
 const etags = new Map();
 
 const calculateSha = (handlers, absolutePath) =>
@@ -387,7 +400,8 @@ const renderDirectory = async (current, acceptsJSON, handlers, methods, config,
 
 		details.relative = path.join(relativePath, details.base);
 
-		if (stats.isDirectory()) {
+		//if (stats.isDirectory()) {
+		if (await handlers.isDirectoryOrDirectorySymbolicLink(filePath, 10)) {
 			details.base += slashSuffix;
 			details.relative += slashSuffix;
 			details.type = 'folder';
@@ -569,7 +583,8 @@ const getHandlers = methods => Object.assign({
 	realpath: promisify(realpath),
 	createReadStream,
 	readdir: promisify(readdir),
-	sendError
+	sendError,
+	isDirectoryOrDirectorySymbolicLink: promisify(isDirectoryOrDirectorySymbolicLink)
 }, methods);
 
 module.exports = async (request, response, config = {}, methods = {}) => {
@@ -668,7 +683,8 @@ module.exports = async (request, response, config = {}, methods = {}) => {
 		}
 	}
 
-	if (stats && stats.isDirectory()) {
+	//if (stats && stats.isDirectory()) {
+	if (stats && await handlers.isDirectoryOrDirectorySymbolicLink(absolutePath, 10)) {
 		let directory = null;
 		let singleFile = null;