Debug Environment Variables in Apache VirtualHost
<p>I'm using ProxyPass while attempting to set a request header in my vhost w/:</p>

<pre><code>&lt;VirtualHost *:443&gt;
    ...
    RequestHeader set X-REMOTE-USER "%{REMOTE_USER}s"
    ProxyPass / http://127.0.0.1:9292/
    ProxyPassReverse / http://127.0.0.1:9292/
    ...
&lt;/VirtualHost&gt;
</code></pre>

<p>However when inspecting the headers that are getting sent to my application running on port 9292 I see:</p>

<pre><code>"HTTP_X_REMOTE_USER"=&gt;"(null)" 
</code></pre>

<p>Does this mean that <code>REMOTE_USER</code> is not set or am I using <code>RequestHeader</code> incorrectly? Is there a way to debug what environment variables I have available to me within the vhost?</p>