Stackify Prefix sfclient ERR_CONNECTION_REFUSED

Question

Two part question that may or may not be related to each other.

I am running Stackify Prefix v3.0.28 for a Java application on Win10 and it generally seems to work OK: I can see the traces of various actions in our application.

Part 1:

When navigating to any page of our application I get two failed requests to load JS files:

http://127.0.0.1:2/scripts/sfclient.xhr.min.js
http://127.0.0.1:2/scripts/sfclient.perf.prefix.min.js

Both of these requests fail with ERR_CONNECTION_REFUSED. Those script references are not in my JSP page so I assume they are injected by Prefix.

Here is the raw HTML that tries to load the 2 scripts:

<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><script src="http://127.0.0.1:2/scripts/sfclient.xhr.min.js"></script>
    <script>var SPerfLib = window.SPerfLib || {}; SPerfLib.RequestId = '54fd58d1-7f7e-d3a4-0001-331676a83598'; if(!SPerfLib.isAttached) { document.addEventListener('DOMContentLoaded', function() { var l = document.createElement('script'); l.src = 'http://127.0.0.1:2/scripts/sfclient.perf.prefix.min.js'; document.body.appendChild(l);}); SPerfLib.isAttached = true;}</script>

I have tried looking for configuration options, but found none. I was not sure if the scripts should be server from port 2 or not. The Prefix trace output is from port 2012 and that seems correct.

I tried uninstalling and re-installing Prefix, but with the same results. There does not seem to be any later version of Prefix to try.

How do I get those scripts to load successfully?

Part 2:

On one particular page we have an XHR to retrieve some JSON data. The server is returning data correctly, but it is somehow deleted before it arrives at the browser. The response headers show status 200 but 0 bytes content-length , which then causes some of our JS on the page to fail. If I run the same thing w/o Prefix everything works as expected - status is still 200, but content-length is 37 and JSON payload is visible.

This is the response header for the XHR when Prefix is in play (note content-length: 0 )

cache-control: no-cache, must-revalidate
content-language: en-US
content-length: 0
content-type: text/html
date: Mon, 31 Aug 2020 14:19:24 GMT
expires: Thu, 01 Jan 1970 00:00:00 GMT
last-modified: Mon, 31 Aug 2020 14:19:24 GMT
pragma: no-cache
server: WildFly/10
status: 200
x-powered-by: Undertow/1
x-powered-by: JSP/2.3
x-stackifyid: V1|8bbdce1c-a507-bbdc-0001-3378bff33740|

If I remove the Stackify agent from the JVM options and disable the profiler, then the response header looks like this:

cache-control: no-cache, must-revalidate
content-language: en-US
content-length: 37
content-type: text/html;charset=UTF-8
date: Mon, 31 Aug 2020 14:25:12 GMT
expires: Thu, 01 Jan 1970 00:00:00 GMT
last-modified: Mon, 31 Aug 2020 14:25:12 GMT
pragma: no-cache
server: WildFly/10
status: 200
x-powered-by: Undertow/1

I'm appreciative of any suggestions!

Answer 1

These issues you are having with Prefix are known issues with Prefix. We are working on a complete re-write of Prefix (a reason why there has been such a big delay since our last release) and these items are things we are getting fixed in the new Prefix version. We are getting very close to releasing a Beta for Prefix, if you would like to be on the list to give the Prefix beta a try email the Stackify Support Team support@stackify.com