From c4dc841175f40b2ff7ebb13b17247ebca4ec0d5b Mon Sep 17 00:00:00 2001
From: Rif'at Ahdi Ramadhani <10791791+atrifat@users.noreply.github.com>
Date: Tue, 31 Oct 2023 10:52:45 +0800
Subject: [PATCH] Add support forward req headers (#14) fix #13

* feat: add support for forwarding req headers

* chore: update .env.sample w/ forward headers
---
 .env.sample | 2 ++
 filter.ts   | 8 +++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/.env.sample b/.env.sample
index 9ad502e..64cdd5b 100644
--- a/.env.sample
+++ b/.env.sample
@@ -8,5 +8,7 @@ BLOCKED_PUBKEYS=
 WHITELISTED_PUBKEYS=
 # Set true to filter proxy events
 FILTER_PROXY_EVENTS=
+# Set true to enable forwarding of request headers to upstream server
+ENABLE_FORWARD_REQ_HEADERS=false
 # Use classification result from monitoring bot as filter data
 NOSTR_MONITORING_BOT_PUBLIC_KEY=
diff --git a/filter.ts b/filter.ts
index 64672fe..779b67d 100644
--- a/filter.ts
+++ b/filter.ts
@@ -127,6 +127,8 @@ const whitelistedPubkeys: string[] =
     : [];
 // Filter proxy events
 const filterProxyEvents = process.env.FILTER_PROXY_EVENTS === "true";
+// Forward request headers to upstream
+const enableForwardReqHeaders = process.env.ENABLE_FORWARD_REQ_HEADERS === "true";
 
 // クライアントIPアドレスのCIDRフィルタ
 const cidrRanges: string[] = [
@@ -487,8 +489,12 @@ async function listen(): Promise<void> {
       // ソケットごとにユニークなIDを付与
       const socketId = uuidv4();
 
+      // Check whether we want to forward original request headers to the upstream server
+      // This will be useful if the upstream server need original request headers to do operations like rate-limiting, etc.
+      let wsClientOptions = enableForwardReqHeaders ? { headers: req.headers } : undefined;
+
       // 上流となるリレーサーバーと接続
-      let upstreamSocket = new WebSocket(upstreamWsUrl);
+      let upstreamSocket = new WebSocket(upstreamWsUrl, wsClientOptions);
       connectUpstream(upstreamSocket, downstreamSocket);
 
       // クライアントとの接続が確立したら、アイドルタイムアウトを設定