fix(http): remove AbortSignal event listeners when requests complete (#1332)

Author: paulbrimicombe

.changeset/four-carrots-tap.md

@@ -0,0 +1,6 @@
+---
+"@smithy/fetch-http-handler": patch
+"@smithy/node-http-handler": patch
+---
+
+remove abort signal event listeners after request completion

packages/fetch-http-handler/src/fetch-http-handler.ts

@@ -127,6 +127,8 @@ export class FetchHttpHandler implements HttpHandler<FetchHttpHandlerConfig> {
       requestOptions.keepalive = keepAlive;
     }
 
+    let removeSignalEventListener = null as null | (() => void);
+
     const fetchRequest = new Request(url, requestOptions);
     const raceOfPromises = [
       fetch(fetchRequest).then((response) => {
@@ -173,15 +175,17 @@ export class FetchHttpHandler implements HttpHandler<FetchHttpHandlerConfig> {
           };
           if (typeof (abortSignal as AbortSignal).addEventListener === "function") {
             // preferred.
-            (abortSignal as AbortSignal).addEventListener("abort", onAbort);
+            const signal = abortSignal as AbortSignal;
+            signal.addEventListener("abort", onAbort, { once: true });
+            removeSignalEventListener = () => signal.removeEventListener("abort", onAbort);
           } else {
             // backwards compatibility
             abortSignal.onabort = onAbort;
           }
         })
       );
     }
-    return Promise.race(raceOfPromises);
+    return Promise.race(raceOfPromises).finally(removeSignalEventListener);
   }
 
   updateHttpClientConfig(key: keyof FetchHttpHandlerConfig, value: FetchHttpHandlerConfig[typeof key]): void {

packages/node-http-handler/src/node-http-handler.ts

@@ -252,7 +252,9 @@ or increase socketAcquisitionWarningTimeout=(millis) in the NodeHttpHandler conf
         };
         if (typeof (abortSignal as AbortSignal).addEventListener === "function") {
           // preferred.
-          (abortSignal as AbortSignal).addEventListener("abort", onAbort);
+          const signal = abortSignal as AbortSignal;
+          signal.addEventListener("abort", onAbort, { once: true });
+          req.once("close", () => signal.removeEventListener("abort", onAbort));
         } else {
           // backwards compatibility
           abortSignal.onabort = onAbort;

packages/node-http-handler/src/node-http2-handler.ts

@@ -189,7 +189,9 @@ export class NodeHttp2Handler implements HttpHandler<NodeHttp2HandlerOptions> {
         };
         if (typeof (abortSignal as AbortSignal).addEventListener === "function") {
           // preferred.
-          (abortSignal as AbortSignal).addEventListener("abort", onAbort);
+          const signal = abortSignal as AbortSignal;
+          signal.addEventListener("abort", onAbort, { once: true });
+          req.once("close", () => signal.removeEventListener("abort", onAbort));
         } else {
           // backwards compatibility
           abortSignal.onabort = onAbort;