From 4aa31b4435bfe4f05b88faf077b4e34cfbe09518 Mon Sep 17 00:00:00 2001
From: Marcin Jahn <10273406+marcinjahn@users.noreply.github.com>
Date: Mon, 17 Nov 2025 10:09:01 +0100
Subject: [PATCH] fix: cancellation of requests with body

The current implementation works well only for HTTP methods that do not support request body.
For requests like POST, `req`'s 'close' event fires as soon as request body is read (see https://github.com/expressjs/express/issues/6334#issuecomment-2663645929).
I changed it to use `res`'s 'close', which works as expected.
"finish" fires before "close", so I added `requestFinished` flag to avoid cancellation when the request is already processed.
---
 src/abort-controller.middleware.ts | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/abort-controller.middleware.ts b/src/abort-controller.middleware.ts
index ca3fea2..b559aa0 100644
--- a/src/abort-controller.middleware.ts
+++ b/src/abort-controller.middleware.ts
@@ -27,13 +27,26 @@ export class AbortControllerMiddleware implements NestMiddleware {
     req.abortController = controller;
     req.abortSignal = controller.signal;
 
-    req.on('close', () => {
+    let requestFinished = false;
+
+    res.on('close', () => {
+      if (requestFinished) {
+        return;
+      }
+      
       if (enableLogging) {
         this.logger.debug(LOG_MESSAGES.CLIENT_DISCONNECTED);
       }
       controller.abort();
     });
 
+    res.on('finish', () => {
+      requestFinished = true;
+      if (enableLogging) {
+        this.logger.debug(LOG_MESSAGES.REQUEST_COMPLETED);
+      }
+    });
+
     if (timeout > 0) {
       const timeoutId = setTimeout(() => {
         if (enableLogging) {
@@ -42,16 +55,10 @@ export class AbortControllerMiddleware implements NestMiddleware {
         controller.abort();
       }, timeout);
 
-      req.on('close', () => clearTimeout(timeoutId));
+      res.on('close', () => clearTimeout(timeoutId));
       res.on('finish', () => clearTimeout(timeoutId));
     }
 
-    res.on('finish', () => {
-      if (enableLogging) {
-        this.logger.debug(LOG_MESSAGES.REQUEST_COMPLETED);
-      }
-    });
-
     next();
   }
 }