Special case set-cookie

fixtures/worker-app/package.json

@@ -13,11 +13,12 @@
 		"type:tests": "tsc -p ./tests/tsconfig.json"
 	},
 	"devDependencies": {
-		"wrangler": "workspace:*",
 		"@cloudflare/workers-tsconfig": "workspace:^",
-		"undici": "^5.28.2"
+		"undici": "^5.28.2",
+		"wrangler": "workspace:*"
 	},
 	"dependencies": {
+		"cookie": "^0.6.0",
 		"isomorphic-random-example": "workspace:^"
 	}
 }

fixtures/worker-app/src/index.js

@@ -1,3 +1,4 @@
+import cookie from "cookie";
 import { randomBytes } from "isomorphic-random-example";
 import { now } from "./dep";
 import { logErrors } from "./log";
@@ -15,10 +16,35 @@ export default {
 	async fetch(request) {
 		console.log("request log");
 
-		const { pathname, origin } = new URL(request.url);
+		const { pathname, origin, hostname, host } = new URL(request.url);
 		if (pathname === "/random") return new Response(hexEncode(randomBytes(8)));
 		if (pathname === "/error") throw new Error("Oops!");
 		if (pathname === "/redirect") return Response.redirect(`${origin}/foo`);
+		if (pathname === "/cookie")
+			return new Response("", {
+				headers: [
+					[
+						"Set-Cookie",
+						cookie.serialize("hello", "world", {
+							domain: hostname,
+						}),
+					],
+					[
+						"Set-Cookie",
+						cookie.serialize("hello2", "world2", {
+							domain: host,
+							secure: true,
+						}),
+					],
+					[
+						"Set-Cookie",
+						cookie.serialize("hello2", "world2", {
+							domain: `${hostname}:1`,
+						}),
+					],
+				],
+			});
+
 		if (request.headers.get("X-Test-URL") !== null) {
 			return new Response(request.url);
 		}

fixtures/worker-app/tests/index.test.ts

@@ -139,4 +139,17 @@ describe("'wrangler dev' correctly renders pages", () => {
 			`http://${ip}:${port}/foo`
 		);
 	});
+
+	it("rewrites set-cookie headers to the hostname, not host", async ({
+		expect,
+	}) => {
+		const response = await fetch(`http://${ip}:${port}/cookie`);
+		expect(response.headers.getSetCookie()).toMatchInlineSnapshot(`
+			[
+			  "hello=world; Domain=prod.example.org",
+			  "hello2=world2; Domain=prod.example.org; Secure",
+			  "hello2=world2; Domain=prod.example.org:1",
+			]
+		`);
+	});
 });

packages/wrangler/templates/startDevWorker/ProxyWorker.ts

@@ -304,13 +304,22 @@ function insertLiveReloadScript(
  * so that this proxy is transparent to the Client Browser and User Worker.
  */
 function rewriteUrlRelatedHeaders(headers: Headers, from: URL, to: URL) {
+	const setCookie = headers.getAll("Set-Cookie");
+	headers.delete("Set-Cookie");
+	for (const cookie of setCookie) {
+		headers.append(
+			"Set-Cookie",
+			cookie.replace(
+				new RegExp(`Domain=${from.hostname}($|;|,)`),
+				`Domain=${to.hostname}$1`
+			)
+		);
+	}
 	headers.forEach((value, key) => {
-		if (typeof value === "string" && value.includes(from.hostname)) {
+		if (typeof value === "string" && value.includes(from.host)) {
 			headers.set(
 				key,
-				value
-					.replaceAll(from.origin, to.origin)
-					.replaceAll(from.hostname, to.hostname)
+				value.replaceAll(from.origin, to.origin).replaceAll(from.host, to.host)
 			);
 		}
 	});