From fcec1f44ada51099f56cbd8089a70c57e54ba28c Mon Sep 17 00:00:00 2001
From: Damien Arrachequesne <damien.arrachequesne@gmail.com>
Date: Wed, 18 Sep 2024 15:56:20 +0200
Subject: [PATCH] fix(eio): discard all pending packets when the server is
 closed

---
 packages/engine.io/lib/socket.ts  |  8 +++-
 packages/engine.io/test/server.js | 61 +++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 2 deletions(-)

diff --git a/packages/engine.io/lib/socket.ts b/packages/engine.io/lib/socket.ts
index 3ec838e3a..bd8ff655f 100644
--- a/packages/engine.io/lib/socket.ts
+++ b/packages/engine.io/lib/socket.ts
@@ -554,6 +554,10 @@ export class Socket extends EventEmitter {
    * @return {Socket} for chaining
    */
   public close(discard?: boolean) {
+    if (discard && (this.readyState === "open" || this.readyState === "closing")) {
+      return this.closeTransport(discard);
+    }
+
     if ("open" !== this.readyState) return;
 
     this.readyState = "closing";
@@ -570,7 +574,7 @@ export class Socket extends EventEmitter {
       return;
     }
 
-    debug("the buffer is empty, closing the transport right away", discard);
+    debug("the buffer is empty, closing the transport right away");
     this.closeTransport(discard);
   }
 
@@ -581,7 +585,7 @@ export class Socket extends EventEmitter {
    * @private
    */
   private closeTransport(discard: boolean) {
-    debug("closing the transport (discard? %s)", discard);
+    debug("closing the transport (discard? %s)", !!discard);
     if (discard) this.transport.discard();
     this.transport.close(this.onClose.bind(this, "forced close"));
   }
diff --git a/packages/engine.io/test/server.js b/packages/engine.io/test/server.js
index 25d87ce45..35b198835 100644
--- a/packages/engine.io/test/server.js
+++ b/packages/engine.io/test/server.js
@@ -1634,6 +1634,67 @@ describe("server", () => {
       });
     });
 
+    it("should discard the packets in the writeBuffer when stopping the server", (done) => {
+      engine = listen((port) => {
+        const clientSocket = new ClientSocket(`ws://localhost:${port}`);
+
+        clientSocket.on("data", () => {
+          done(new Error("should not happen"));
+        });
+
+        clientSocket.on("close", (reason) => {
+          expect(reason).to.eql("transport error");
+
+          clientSocket.close();
+          done();
+        });
+
+        engine.on("connection", (socket) => {
+          socket.write("hello");
+          engine.close();
+        });
+      });
+    });
+
+    it("should discard the packets in the writeBuffer when stopping the server (2)", (done) => {
+      engine = listen((port) => {
+        const clientSocket = new ClientSocket(`ws://localhost:${port}`);
+
+        clientSocket.on("data", () => {
+          done(new Error("should not happen"));
+        });
+
+        clientSocket.on("close", (reason) => {
+          expect(reason).to.eql("transport error");
+
+          clientSocket.close();
+          done();
+        });
+
+        engine.on("connection", (socket) => {
+          socket.write("hello");
+          socket.close(); // readyState is now "closing"
+          engine.close();
+        });
+      });
+    });
+
+    it("should not discard the packets in the writeBuffer when closing gracefully", (done) => {
+      engine = listen((port) => {
+        const clientSocket = new ClientSocket(`ws://localhost:${port}`);
+
+        clientSocket.on("data", (val) => {
+          expect(val).to.eql("hello");
+          done();
+        });
+
+        engine.on("connection", (socket) => {
+          socket.write("hello");
+          socket.close();
+        });
+      });
+    });
+
     describe("graceful close", () => {
       before(function () {
         if (process.env.EIO_WS_ENGINE === "uws") {