Re: Re: Proxying From Directory To App On Port (Apache Users)

On Tue, Aug 25, 2015 at 10:25 PM, Steven Shi <steven200796@xxxxxxxxx> wrote:

The "app" consists of a maven built java back-end which utilizes the maven build of apache spark ("http://sparkjava.com/"). To my understanding, the spark API initiates a Jetty server which listens on a specified port for GET / POST requests. It then either processes the data sent in a POST request or simply returns the html/css/js page for a GET request.

You really need to stop using the term "app" for every piece of software involved in this problem. You've used "app" to refer to the jQuery client front end and the Java backend and possibly the Apache HTTP middle layer. Not to mention the URI prefix being proxied.

When I said "the port 2000 is lost", I meant that if I go in to the app through the proxy /app and attempt to issue GET / POST commands via the jQuery front end interface, google's developer console shows the remote address as my_ip:(80, 443) and the request URL is simply my_hostname/command. Likewise, the origin and the host are incorrect.

I can't tell from the Chrome developer console snapshot if the "POST https://stevenshi.me/run" request that failed with a 404 status was due to a redirect or if it was the original request made by the browser client code. If it was the original request then something is wrong in how you have told the client code which URI to use. If it was due to a redirect the question becomes whether the redirect is from Apache or your Spark backend.

I'm willing to bet the problem is the Spark backend is issuing a HTTP redirect that leads to the Apache middle layer no knowing how to handle the subsequent request. The solution might be as simple as enabling rewriting of proxied HTML with this directive in your virtual host:

ProxyHTMLEnable On

That will require an appropriate "LoadModule proxy_html_module" in your Apache config.

Your Apache config proxies the URI prefix "/projects/CS32Brewer/". Is that the URI prefix your browser client code is using? Does the Apache access log show requests from the browser with the URI prefix? Have you enabled higher levels of debug output from Apache as I suggested? If so what does the Apache error log show for a failing request?

If HTTP_HOST is the "Host:" shown in google dev console "Request Headers", the app is not setting it correctly on /app (it is "my_hostname" rather than "my_hostname:2000").
If HTTP_HOST is not what's said above, then how do I check what it is?

What do you mean by "correctly on /app"? Nowhere in the data you've provided so far, in particular the Apache virtual host configuration, is a URI prefix of "/app" referenced. If you're using that as a synonym for "/projects/CS32Brewer" please say so.

Kurtis Rader

Caretaker of the exceptional canines Junior and Hank