Handle cases where res.write throws

lib/node-http-proxy.js

@@ -513,9 +513,17 @@ HttpProxy.prototype.proxyRequest = function (req, res, options) {
 
     // For each data `chunk` received from the `reverseProxy`
     // `response` write it to the outgoing `res`.
+    // If the res socket has been killed already, then write()
+    // will throw. Nevertheless, try our best to end it nicely.
     response.on('data', function (chunk) {
-      if (req.method !== 'HEAD') {
+      if (req.method !== 'HEAD' && res.writable) {
+        try {
           res.write(chunk);
+        } catch (er) {
+          try {
+            res.end();
+          } catch (er) {}
+        }
       }
     });