fix(vnda): filter proxy cookies to prevent RequestHeaderSectionTooLarge (#1633)

Add allowedCookies option to proxy handler and configure VNDA proxy to
only forward VNDA-relevant cookies (vnda_cart_id, cart_id, ahoy_visit,
ahoy_visitor), stripping analytics/tracking cookies that inflate headers
beyond the 8KB limit.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: guitavano

vnda/loaders/proxy.ts

@@ -38,6 +38,12 @@ const API_PATHS = [
 const decoSiteMapUrl = "/sitemap/deco.xml";
 
 const VNDA_HOST_HEADER = "X-Shop-Host";
+const VNDA_ALLOWED_COOKIES = [
+  "vnda_cart_id",
+  "cart_id",
+  "ahoy_visit",
+  "ahoy_visitor",
+];
 export interface Props {
   /** @description ex: /p/fale-conosco */
   pagesToProxy?: string[];
@@ -100,6 +106,7 @@ function loader(
           : internalDomain,
         host: url.hostname,
         customHeaders,
+        allowedCookies: VNDA_ALLOWED_COOKIES,
       },
     },
   }));
@@ -123,6 +130,7 @@ function loader(
         url: `https://api.vnda.com.br/`,
         host: url.hostname,
         customHeaders,
+        allowedCookies: VNDA_ALLOWED_COOKIES,
       },
     },
   }));

website/handlers/proxy.ts

@@ -24,6 +24,23 @@ export const removeCFHeaders = (headers: Headers) => {
     }
   });
 };
+export const filterCookies = (headers: Headers, allowed: string[]) => {
+  const cookie = headers.get("cookie");
+  if (!cookie) return;
+  const filtered = cookie
+    .split(";")
+    .map((c) => c.trim())
+    .filter((c) => {
+      const name = c.split("=")[0]?.trim();
+      return name && allowed.includes(name);
+    })
+    .join("; ");
+  if (filtered) {
+    headers.set("cookie", filtered);
+  } else {
+    headers.delete("cookie");
+  }
+};
 /**
  * @title {{{key}}} - {{{value}}}
  */
@@ -86,6 +103,10 @@ export interface Props {
   removeDirtyCookies?: boolean;
   excludeHeaders?: string[];
   pathsThatRequireSameReferer?: string[];
+  /**
+   * @description Only forward cookies whose names match this list. When set, all other cookies are stripped from the proxied request.
+   */
+  allowedCookies?: string[];
 }
 /**
  * @title Proxy
@@ -104,6 +125,7 @@ export default function Proxy({
   replaces,
   removeDirtyCookies = false,
   pathsThatRequireSameReferer = [],
+  allowedCookies,
 }: Props): Handler {
   return async (req, _ctx) => {
     const url = new URL(req.url);
@@ -127,6 +149,9 @@ export default function Proxy({
     if (removeDirtyCookies) {
       removeDirtyCookiesFn(headers);
     }
+    if (allowedCookies && allowedCookies.length > 0) {
+      filterCookies(headers, allowedCookies);
+    }
     if (isFreshCtx<DecoSiteState>(_ctx)) {
       _ctx?.state?.monitoring?.logger?.log?.("proxy sent headers", headers);
     }