From 3bc4afec7737e6a3f3bf648595cb06c4d54bf697 Mon Sep 17 00:00:00 2001
From: Laura Hausmann <laura@hausmann.dev>
Date: Sat, 7 Oct 2023 00:13:23 +0200
Subject: [PATCH] [mastodon-client] Set correct access-control-expose-headers
 response header

---
 packages/backend/src/server/api/mastodon/index.ts      |  2 ++
 .../src/server/api/mastodon/middleware/set-headers.ts  | 10 ++++++++++
 2 files changed, 12 insertions(+)
 create mode 100644 packages/backend/src/server/api/mastodon/middleware/set-headers.ts

diff --git a/packages/backend/src/server/api/mastodon/index.ts b/packages/backend/src/server/api/mastodon/index.ts
index aece784bc..80227094b 100644
--- a/packages/backend/src/server/api/mastodon/index.ts
+++ b/packages/backend/src/server/api/mastodon/index.ts
@@ -17,6 +17,7 @@ import { CacheMiddleware } from "@/server/api/mastodon/middleware/cache.js";
 import { KoaBodyMiddleware } from "@/server/api/mastodon/middleware/koa-body.js";
 import { NormalizeQueryMiddleware } from "@/server/api/mastodon/middleware/normalize-query.js";
 import { PaginationMiddleware } from "@/server/api/mastodon/middleware/pagination.js";
+import { SetHeadersMiddleware } from "@/server/api/mastodon/middleware/set-headers.js";
 
 export const logger = apiLogger.createSubLogger("mastodon");
 export type MastoContext = RouterContext & DefaultContext;
@@ -37,6 +38,7 @@ export function setupMastodonApi(router: Router): void {
 
 function setupMiddleware(router: Router): void {
     router.use(KoaBodyMiddleware());
+    router.use(SetHeadersMiddleware);
     router.use(CatchErrorsMiddleware);
     router.use(NormalizeQueryMiddleware);
     router.use(PaginationMiddleware);
diff --git a/packages/backend/src/server/api/mastodon/middleware/set-headers.ts b/packages/backend/src/server/api/mastodon/middleware/set-headers.ts
new file mode 100644
index 000000000..0e073e673
--- /dev/null
+++ b/packages/backend/src/server/api/mastodon/middleware/set-headers.ts
@@ -0,0 +1,10 @@
+import { MastoContext } from "@/server/api/mastodon/index.js";
+
+const headers = {
+    "Access-Control-Expose-Headers": "Link,Connection,Sec-Websocket-Accept,Upgrade"
+};
+
+export async function SetHeadersMiddleware(ctx: MastoContext, next: () => Promise<any>) {
+    ctx.set(headers);
+    await next();
+}
\ No newline at end of file