From 844c487ee865c512236e001907d82f89864ff2fd Mon Sep 17 00:00:00 2001
From: Ethan Davidson <31261035+EthanThatOneKid@users.noreply.github.com>
Date: Sun, 22 Oct 2023 13:20:20 -0700
Subject: [PATCH] add `withCORS` helper function

---
 lib/api/api.ts | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/lib/api/api.ts b/lib/api/api.ts
index 98c97d0..bc632a4 100644
--- a/lib/api/api.ts
+++ b/lib/api/api.ts
@@ -65,11 +65,11 @@ export function makeAPIRouter(
     )
     .get(
       new URLPattern({ pathname: "/seasons" }),
-      makeSeasonsGetHandler(leaderboardClient),
+      withCORS(makeSeasonsGetHandler(leaderboardClient)),
     )
     .get(
       new URLPattern({ pathname: "/seasons/:season_id" }),
-      makeSeasonGetHandler(leaderboardClient),
+      withCORS(makeSeasonGetHandler(leaderboardClient)),
     );
 }
 
@@ -115,3 +115,21 @@ export function makeOnListen(
 function makeInviteURL(applicationID: string) {
   return `https://discord.com/api/oauth2/authorize?client_id=${applicationID}&scope=applications.commands`;
 }
+
+/**
+ * withCORS wraps a handler with common CORS headers.
+ */
+function withCORS(
+  handle: router.RouterHandler["handle"],
+): router.RouterHandler["handle"] {
+  return async function (request: router.RouterRequest) {
+    const response = await handle(request);
+    response.headers.set("Access-Control-Allow-Origin", "*");
+    response.headers.set("Access-Control-Allow-Methods", "GET, POST");
+    response.headers.set(
+      "Access-Control-Allow-Headers",
+      "Content-Type, Authorization",
+    );
+    return response;
+  };
+}