Revert "[refactor] Improved event handler cleanup "

This reverts commit 9f923325d08ac018a3325beaa9e0805b5eda61e6.

lib/node-http-proxy/http-proxy.js

@@ -236,46 +236,24 @@ HttpProxy.prototype.proxyRequest = function (req, res, buffer) {
 
     res.on('drain', ondrain);
 
-    function onend() {
-      cleanup();
-      res.end();
-    }
-
-    function onclose() {
-      cleanup();
-      res.destroy();
-    }
-
-    response.on('close', onclose);
-    response.on('end', onend);
-
-    response.on('error', proxyError);
-    res.on('error', proxyError);
-
-
-    function cleanup() {
-      response.removeListener('data', ondata);
-      res.removeListener('drain', ondrain);
-
-      response.removeListener('end', onend);
-      response.removeListener('close', onclose);
-
-      response.removeListener('error', proxyError);
-      res.removeListener('error', proxyError);
-
-      response.removeListener('end', cleanup);
-      response.removeListener('close', cleanup);
-
-      res.removeListener('end', cleanup);
-      res.removeListener('close', cleanup);
-    }
-
-    response.on('end', cleanup);
-    response.on('close', cleanup);
-
-    res.on('end', cleanup);
-    res.on('close', cleanup);
-
+    //
+    // When the `reverseProxy` `response` ends, end the
+    // corresponding outgoing `res` unless we have entered
+    // an error state. In which case, assume `res.end()` has
+    // already been called and the 'error' event listener
+    // removed.
+    //
+    response.on('end', function () {
+      if (!errState) {
+        reverseProxy.removeListener('error', proxyError);
+        
+        try { res.end() }
+        catch (ex) { console.error("res.end error: %s", ex.message) }
+        
+        // Emit the `end` event now that we have completed proxying
+        self.emit('end', req, res);
+      }
+    });
   });
 
   //