Set correct Host header with --upstream

Author: mrbbot

packages/core/src/standards/event.ts

@@ -405,7 +405,6 @@ export class ServiceWorkerGlobalScope extends WorkerGlobalScope {
       }
     }
 
-    request.headers.delete("host");
     // noinspection ES6MissingAwait
     const waitUntil = Promise.all(event[kWaitUntil]) as Promise<WaitUntil>;
     return withWaitUntil(await fetch(request[kInner]), waitUntil);

packages/http-server/src/index.ts

@@ -87,6 +87,9 @@ export async function convertNodeRequest(
   req.headers["cf-ray"] ??= randomHex(16);
   req.headers["cf-visitor"] ??= `{"scheme":"${proto}"}`;
 
+  // Make sure we're using the correct host header (with custom upstream)
+  req.headers["host"] = url.host;
+
   // Build Headers object from request
   const headers = new Headers();
   for (const [name, values] of Object.entries(req.headers)) {

packages/http-server/test/index.spec.ts

@@ -102,10 +102,12 @@ function request(
 }
 
 test("convertNodeRequest: uses request url, with upstream or host as base", async (t) => {
-  let [, url] = await buildConvertNodeRequest(t, {
+  // eslint-disable-next-line prefer-const
+  let [request, url] = await buildConvertNodeRequest(t, {
     path: "/test",
     upstream: "http://upstream.com",
   });
+  t.is(request.headers.get("host"), "upstream.com");
   t.is(url.toString(), "http://upstream.com/test");
 
   [, url] = await buildConvertNodeRequest(t, { path: "/test" });

packages/web-sockets/src/fetch.ts

@@ -16,9 +16,6 @@ export async function upgradingFetch(
 ): Promise<Response> {
   const request = new Request(input, init);
 
-  // Cloudflare ignores request Host
-  request.headers.delete("host");
-
   // Handle web socket upgrades
   if (
     request.method === "GET" &&