POC: Request through undici

lib/http-proxy/common.ts

@@ -1,4 +1,8 @@
-import type { NormalizedServerOptions, ProxyTargetDetailed, ServerOptions } from "./index";
+import type {
+  NormalizedServerOptions,
+  ProxyTargetDetailed,
+  ServerOptions,
+} from "./index";
 import { type IncomingMessage as Request } from "node:http";
 import { TLSSocket } from "node:tls";
 import type { Socket } from "node:net";
@@ -17,6 +21,7 @@ export interface Outgoing extends Outgoing0 {
   headers: { [header: string]: string | string[] | undefined } & {
     overwritten?: boolean;
   };
+  url: string;
 }
 
 // If we allow this header and a user sends it with a request,
@@ -28,11 +33,13 @@ export interface Outgoing extends Outgoing0 {
 const HEADER_BLACKLIST = "trailer";
 
 const HTTP2_HEADER_BLACKLIST = [
-  ':method',
-  ':path',
-  ':scheme',
-  ':authority',
-]
+  ":method",
+  ":path",
+  ":scheme",
+  ":authority",
+  "connection",
+  "keep-alive",
+];
 
 // setupOutgoing -- Copies the right headers from `options` and `req` to
 // `outgoing` which is then used to fire the proxied request by calling
@@ -51,8 +58,10 @@ export function setupOutgoing(
   // the final path is target path + relative path requested by user:
   const target = options[forward || "target"]!;
 
-  outgoing.port =
-    +(target.port ?? (target.protocol !== undefined && isSSL.test(target.protocol) ? 443 : 80));
+  outgoing.port = +(
+    target.port ??
+    (target.protocol !== undefined && isSSL.test(target.protocol) ? 443 : 80)
+  );
 
   for (const e of [
     "host",
@@ -125,7 +134,9 @@ export function setupOutgoing(
 
   // target if defined is a URL object so has attribute "pathname", not "path".
   const targetPath =
-    target && options.prependPath !== false && 'pathname' in target ? getPath(`${target.pathname}${target.search ?? ""}`) : "/";
+    target && options.prependPath !== false && "pathname" in target
+      ? getPath(`${target.pathname}${target.search ?? ""}`)
+      : "/";
 
   let outgoingPath = options.toProxy ? req.url : getPath(req.url);
 
@@ -139,11 +150,25 @@ export function setupOutgoing(
   if (options.changeOrigin) {
     outgoing.headers.host =
       target.protocol !== undefined &&
-      required(outgoing.port, target.protocol) &&
-      !hasPort(outgoing.host)
+        required(outgoing.port, target.protocol) &&
+        !hasPort(outgoing.host)
         ? outgoing.host + ":" + outgoing.port
         : outgoing.host;
   }
+
+  outgoing.url = ("href" in target &&
+    target.href) ||
+    (target.protocol === "https" ? "https" : "http") +
+    "://" +
+    outgoing.host +
+    (outgoing.port ? ":" + outgoing.port : "");
+
+  if (req.httpVersionMajor > 1) {
+    for (const header of HTTP2_HEADER_BLACKLIST) {
+      delete outgoing.headers[header];
+    }
+  }
+
   return outgoing;
 }
 
@@ -281,17 +306,23 @@ function hasPort(host: string): boolean {
 }
 
 function getPath(url?: string): string {
-  if (url === '' || url?.startsWith('?')) {
-    return url
+  if (url === "" || url?.startsWith("?")) {
+    return url;
   }
   const u = toURL(url);
   return `${u.pathname ?? ""}${u.search ?? ""}`;
 }
 
-export function toURL(url: URL | urllib.Url | ProxyTargetDetailed | string | undefined): URL {
+export function toURL(
+  url: URL | urllib.Url | ProxyTargetDetailed | string | undefined,
+): URL {
   if (url instanceof URL) {
     return url;
-  } else if (typeof url === "object" && 'href' in url && typeof url.href === "string") {
+  } else if (
+    typeof url === "object" &&
+    "href" in url &&
+    typeof url.href === "string"
+  ) {
     url = url.href;
   }
   if (!url) {