From 96ed20f391bf7dafc1365e52b9352036e30db71c Mon Sep 17 00:00:00 2001
From: Da-Jin Chu <dajinchu@gmail.com>
Date: Thu, 29 Jan 2026 10:52:09 -0500
Subject: [PATCH 1/3] pass res to buildpagecontextinit

---
 bifrost-fastify/index.ts | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/bifrost-fastify/index.ts b/bifrost-fastify/index.ts
index cdab042..fab0310 100644
--- a/bifrost-fastify/index.ts
+++ b/bifrost-fastify/index.ts
@@ -39,7 +39,6 @@ declare module "fastify" {
     /// Only set when proxy mode is false or wrapped
     vikePageContext?: Partial<PageContextServer> | null;
     getLayout: GetLayout | null;
-    customPageContextInit: Partial<Omit<PageContextServer, "headers">> | null;
   }
 }
 
@@ -58,7 +57,8 @@ interface ViteProxyPluginOptions extends Omit<
   host: URL;
   onError?: (error: any, pageContext: RenderedPageContext) => void;
   buildPageContextInit?: (
-    req: FastifyRequest
+    req: FastifyRequest<RequestGenericInterface, RawServerBase>,
+    res?: RawServerResponse<RawServerBase>
   ) => Promise<Partial<Omit<PageContextServer, "headers">>>;
   beforeWrappedRender?: (
     req: FastifyRequest<RequestGenericInterface, RawServerBase>,
@@ -109,7 +109,6 @@ export const viteProxyPlugin: FastifyPluginAsync<
   fastify.decorateRequest("bifrostSentProxyHeaders", false);
   fastify.decorateRequest("vikePageContext", null);
   fastify.decorateRequest("getLayout", null);
-  fastify.decorateRequest("customPageContextInit", null);
   await fastify.register(proxy, {
     ...opts,
     upstream: upstream.href,
@@ -119,14 +118,14 @@ export const viteProxyPlugin: FastifyPluginAsync<
         (req.method === "GET" || req.method === "HEAD") &&
         req.accepts().type(["html"]) === "html"
       ) {
-        req.customPageContextInit = buildPageContextInit
+        const customPageContextInit = buildPageContextInit
           ? await buildPageContextInit(req)
           : {};
 
         const pageContextInit = {
           urlOriginal: req.url,
           headersOriginal: req.headers,
-          ...req.customPageContextInit,
+          ...customPageContextInit,
         };
 
         const pageContext = await renderPage(pageContextInit);
@@ -263,7 +262,7 @@ export const viteProxyPlugin: FastifyPluginAsync<
             headInnerHtml,
             proxyLayoutInfo,
           } satisfies WrappedServerOnly,
-          ...req.customPageContextInit,
+          ...(buildPageContextInit ? await buildPageContextInit(req, res) : {}),
         };
         const pageContext = await renderPage(pageContextInit);
         req.vikePageContext = pageContext;

From 30da6021bd5de966f392abb09e2843b89e70c707 Mon Sep 17 00:00:00 2001
From: Da-Jin Chu <dajinchu@gmail.com>
Date: Thu, 29 Jan 2026 10:57:00 -0500
Subject: [PATCH 2/3] beforeWrappedRender

---
 bifrost-fastify/index.ts | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/bifrost-fastify/index.ts b/bifrost-fastify/index.ts
index fab0310..cdab042 100644
--- a/bifrost-fastify/index.ts
+++ b/bifrost-fastify/index.ts
@@ -39,6 +39,7 @@ declare module "fastify" {
     /// Only set when proxy mode is false or wrapped
     vikePageContext?: Partial<PageContextServer> | null;
     getLayout: GetLayout | null;
+    customPageContextInit: Partial<Omit<PageContextServer, "headers">> | null;
   }
 }
 
@@ -57,8 +58,7 @@ interface ViteProxyPluginOptions extends Omit<
   host: URL;
   onError?: (error: any, pageContext: RenderedPageContext) => void;
   buildPageContextInit?: (
-    req: FastifyRequest<RequestGenericInterface, RawServerBase>,
-    res?: RawServerResponse<RawServerBase>
+    req: FastifyRequest
   ) => Promise<Partial<Omit<PageContextServer, "headers">>>;
   beforeWrappedRender?: (
     req: FastifyRequest<RequestGenericInterface, RawServerBase>,
@@ -109,6 +109,7 @@ export const viteProxyPlugin: FastifyPluginAsync<
   fastify.decorateRequest("bifrostSentProxyHeaders", false);
   fastify.decorateRequest("vikePageContext", null);
   fastify.decorateRequest("getLayout", null);
+  fastify.decorateRequest("customPageContextInit", null);
   await fastify.register(proxy, {
     ...opts,
     upstream: upstream.href,
@@ -118,14 +119,14 @@ export const viteProxyPlugin: FastifyPluginAsync<
         (req.method === "GET" || req.method === "HEAD") &&
         req.accepts().type(["html"]) === "html"
       ) {
-        const customPageContextInit = buildPageContextInit
+        req.customPageContextInit = buildPageContextInit
           ? await buildPageContextInit(req)
           : {};
 
         const pageContextInit = {
           urlOriginal: req.url,
           headersOriginal: req.headers,
-          ...customPageContextInit,
+          ...req.customPageContextInit,
         };
 
         const pageContext = await renderPage(pageContextInit);
@@ -262,7 +263,7 @@ export const viteProxyPlugin: FastifyPluginAsync<
             headInnerHtml,
             proxyLayoutInfo,
           } satisfies WrappedServerOnly,
-          ...(buildPageContextInit ? await buildPageContextInit(req, res) : {}),
+          ...req.customPageContextInit,
         };
         const pageContext = await renderPage(pageContextInit);
         req.vikePageContext = pageContext;

From 585701a4459ce8d00b54dfc363ab3fd08c281e99 Mon Sep 17 00:00:00 2001
From: Da-Jin Chu <dajinchu@gmail.com>
Date: Thu, 29 Jan 2026 13:00:56 -0500
Subject: [PATCH 3/3] ts

---
 bifrost-fastify/index.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/bifrost-fastify/index.ts b/bifrost-fastify/index.ts
index cdab042..1fae502 100644
--- a/bifrost-fastify/index.ts
+++ b/bifrost-fastify/index.ts
@@ -4,6 +4,7 @@ import {
   RawServerBase,
   FastifyPluginAsync,
   RouteGenericInterface,
+  RawReplyDefaultExpression,
 } from "fastify";
 import { FastifyRequest, RequestGenericInterface } from "fastify/types/request";
 import proxy, { type FastifyHttpProxyOptions } from "@fastify/http-proxy";
@@ -16,7 +17,6 @@ import { extractDomElements } from "./lib/extractDomElements";
 import { Http2ServerRequest } from "http2";
 import { text } from "node:stream/consumers";
 import { parse as parseContentType } from "fast-content-type-parse";
-import { RawServerResponse } from "@fastify/reply-from";
 
 type RenderedPageContext = Awaited<
   ReturnType<
@@ -62,7 +62,7 @@ interface ViteProxyPluginOptions extends Omit<
   ) => Promise<Partial<Omit<PageContextServer, "headers">>>;
   beforeWrappedRender?: (
     req: FastifyRequest<RequestGenericInterface, RawServerBase>,
-    res: RawServerResponse<RawServerBase>
+    res: RawReplyDefaultExpression<RawServerBase>
   ) => void;
 }
 /**