From e962f48aa9332e411bee182e61967e55af511c30 Mon Sep 17 00:00:00 2001
From: Tataihono Nikora <tataihono.nikora@gmail.com>
Date: Fri, 22 May 2026 07:27:47 +0000
Subject: [PATCH] fix(mastra): normalize Studio proxy encoding

---
 .../src/lib/mastra-proxy.test.ts              | 55 +++++++++++++++++++
 apps/mastra-gateway/src/lib/mastra-proxy.ts   |  5 ++
 2 files changed, 60 insertions(+)
 create mode 100644 apps/mastra-gateway/src/lib/mastra-proxy.test.ts

diff --git a/apps/mastra-gateway/src/lib/mastra-proxy.test.ts b/apps/mastra-gateway/src/lib/mastra-proxy.test.ts
new file mode 100644
index 00000000..0c38f339
--- /dev/null
+++ b/apps/mastra-gateway/src/lib/mastra-proxy.test.ts
@@ -0,0 +1,55 @@
+import { afterEach, describe, expect, it, vi } from "vitest"
+
+describe("Mastra proxy", () => {
+  afterEach(() => {
+    vi.restoreAllMocks()
+    vi.unstubAllEnvs()
+    vi.resetModules()
+  })
+
+  it("requests identity encoding and strips stale response encoding headers", async () => {
+    vi.stubEnv("MASTRA_GATEWAY_BASE_URL", "https://gateway.example.com")
+    vi.stubEnv(
+      "MASTRA_GATEWAY_SESSION_SECRET",
+      "test-secret-test-secret-test-secret-32",
+    )
+    vi.stubEnv("MASTRA_INTERNAL_BASE_URL", "https://mastra.internal")
+    vi.stubEnv("MASTRA_INTERNAL_API_KEY", "internal-key")
+
+    const { createGatewaySessionCookie, GATEWAY_SESSION_COOKIE } =
+      await import("./gateway-session")
+    const { proxyMastraRequest } = await import("./mastra-proxy")
+
+    const token = await createGatewaySessionCookie({
+      subject: "user-1",
+      email: "user@example.com",
+      role: "admin",
+    })
+    const fetchMock = vi.spyOn(globalThis, "fetch").mockResolvedValue(
+      new Response("body{}", {
+        headers: {
+          "content-encoding": "gzip",
+          "content-length": "1024",
+          "content-type": "application/javascript",
+        },
+      }),
+    )
+
+    const response = await proxyMastraRequest(
+      new Request("https://gateway.example.com/studio/assets/index.js", {
+        headers: {
+          "accept-encoding": "gzip, br",
+          cookie: `${GATEWAY_SESSION_COOKIE}=${encodeURIComponent(token)}`,
+        },
+      }),
+      "/studio/assets/index.js",
+    )
+
+    const [, init] = fetchMock.mock.calls[0]
+    const upstreamHeaders = init?.headers as Headers
+    expect(upstreamHeaders.get("accept-encoding")).toBe("identity")
+    expect(response.headers.get("content-encoding")).toBeNull()
+    expect(response.headers.get("content-length")).toBeNull()
+    expect(response.headers.get("content-type")).toBe("application/javascript")
+  })
+})
diff --git a/apps/mastra-gateway/src/lib/mastra-proxy.ts b/apps/mastra-gateway/src/lib/mastra-proxy.ts
index 0de249cb..69c5f377 100644
--- a/apps/mastra-gateway/src/lib/mastra-proxy.ts
+++ b/apps/mastra-gateway/src/lib/mastra-proxy.ts
@@ -17,6 +17,8 @@ const hopByHopHeaders = new Set([
   "upgrade",
 ])
 
+const bodyEncodingHeaders = new Set(["content-encoding", "content-length"])
+
 export async function proxyMastraRequest(
   request: Request,
   upstreamPath: string,
@@ -44,8 +46,10 @@ export async function proxyMastraRequest(
 
   const headers = new Headers(request.headers)
   for (const header of hopByHopHeaders) headers.delete(header)
+  headers.delete("accept-encoding")
   headers.delete("cookie")
   headers.delete("host")
+  headers.set("accept-encoding", "identity")
   headers.set("authorization", `Bearer ${env.MASTRA_INTERNAL_API_KEY}`)
   headers.set("x-forge-user-subject", session.subject)
   if (session.email) headers.set("x-forge-user-email", session.email)
@@ -61,6 +65,7 @@ export async function proxyMastraRequest(
 
   const responseHeaders = new Headers(response.headers)
   for (const header of hopByHopHeaders) responseHeaders.delete(header)
+  for (const header of bodyEncodingHeaders) responseHeaders.delete(header)
 
   return new Response(response.body, {
     status: response.status,