Update index.js

Author: mattcone

src/index.js

@@ -4,9 +4,9 @@ import { includeBytes } from "fastly:experimental";
 import { ConfigStore } from "fastly:config-store";
 
 // Load static files as a Uint8Array at compile time.
-// File path is relative to root of project, not to this file
-const notfoundPage = includeBytes("./src/not-found.html");
-const robotsPage = includeBytes("./src/robots.txt");
+// File path is relative to the root of the project, not this file
+const notfoundPage = includeBytes("src/not-found.html") || new Uint8Array();
+const robotsPage = includeBytes("src/robots.txt") || new Uint8Array();
 
 const handler = async (event) => {
   // get the request from the client
@@ -16,46 +16,58 @@ const handler = async (event) => {
 
   // Prepare logs
   const logger = new Logger("tacolog");
-  logger.log('Request: ' + reqURL);
-  logger.log('User-Agent: ' + req.headers.get('User-Agent'));
+  logger.log(`Request: ${reqURL}`);
+  logger.log(`User-Agent: ${req.headers.get("User-Agent")}`);
 
   // Check if there is a redirect for the URL requested. 
   // If there is, redirect the client.
-  const config = new ConfigStore('redirects');
+  const config = new ConfigStore("redirects");
   const dest = config.get(reqPath);
 
   if (dest) {
     return new Response("", {
       status: 301,
-      headers: { Location: dest },
+      headers: { Location: String(dest) },
     });
   }
 
-  const backendResponse = await fetch(req, {
-    backend: "vcl-origin",
-    cacheOverride: new CacheOverride("pass")
-  });
+  // Fetch from backend
+  let backendResponse;
+  try {
+    backendResponse = await fetch(req, {
+      backend: "vcl-origin",
+      cacheOverride: new CacheOverride("pass"),
+    });
+  } catch (error) {
+    logger.log(`Backend fetch error: ${error}`);
+    return new Response("Internal Server Error", { status: 500 });
+  }
 
   // Handle 404s with a custom response
-  if (backendResponse.status == 404) {
-    return new Response(notfoundPage, {
+  if (backendResponse.status === 404) {
+    return new Response(new Uint8Array(notfoundPage), {
       status: 404,
+      headers: { "Content-Type": "text/html" },
     });
   }
 
   // Return robots.txt with a custom response
   if (reqURL.pathname.endsWith("/robots.txt")) {
-    return new Response(robotsPage, {
+    return new Response(new Uint8Array(robotsPage), {
       status: 200,
+      headers: { "Content-Type": "text/plain" },
     });
   }
 
-  // If status is not 404, send the backend response to the client
-  if (backendResponse.status != 404) {
-    // Add headers to the response back to the client
-    backendResponse.headers.append("x-tacos", "🌮🌮🌮")
-    return backendResponse;
-  }
-}
+  // Clone backend response and modify headers before returning
+  const modifiedResponse = new Response(backendResponse.body, {
+    status: backendResponse.status,
+    statusText: backendResponse.statusText,
+    headers: backendResponse.headers,
+  });
+
+  modifiedResponse.headers.append("x-tacos", "🌮🌮🌮");
+  return modifiedResponse;
+};
 
-addEventListener("fetch", event => event.respondWith(handler(event)));
+addEventListener("fetch", (event) => event.respondWith(handler(event)));