mod_rewrite in Virtual Hosting For Reverse Proxy - mod-rewrite

Question

I'm using Tomcat on port 8080 behind Apache 2.4 on port 443. I've setup the usual reverse proxy configuration on Apache virtual host which is working okay. This is my setup:
<VirtualHost *:443>
ServerName www.example.com
ServerAlias www.example.com
ServerAdmin admin#example.com
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
ProxyRequests Off
<Proxy *>
Order deny,allow
Allow from all
</Proxy>
ProxyPass / http://example.com:8080/
ProxyPassReverse / http:example.com:8080/
<Location />
Order allow,deny
Allow from all
</Location>
SSLEngine on
SSLCertificateFile /etc/ssl/example.com.crt
SSLCertificateKeyFile /etc/ssl/example.com.key
SSLCertificateChainFile /etc/ssl/CA.crt
RewriteEngine On
RewriteCond %{HTTPS} off [OR]
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteCond %{HTTP_HOST} ^(?:www\.)?(.+)$ [NC]
RewriteRule ^ https://www.%1%{REQUEST_URI} [L,NE,R=301]
LogLevel alert rewrite:trace6
RewriteRule ^post$ post.xhtml [NC]
</VirtualHost>
I want to use mod_rewrite on Apache, however, this seems not to be working. I realized that when doing rewrite on .htaccess (which is not applicable in my case), the rewrite rules work okay. However, when I try the same rule from the virtual host, it is not working. For example, using the rule below:
RewriteEngine on
LogLevel alert rewrite:trace6
RewriteRule ^test$ test.php [QSA]
I get the 404 error with the following from the error logs:
[Tue Aug 14 12:12:40.135059 2018] [rewrite:trace2] [pid 11554] mod_rewrite.c(482): [client 127.0.0.1:53326] 127.0.0.1 - - [localhost/sid#7efc776e9518][rid#7efc776710a0/initial] init rewrite engine with requested uri /test
[Tue Aug 14 12:12:40.135108 2018] [rewrite:trace3] [pid 11554] mod_rewrite.c(482): [client 127.0.0.1:53326] 127.0.0.1 - - [localhost/sid#7efc776e9518][rid#7efc776710a0/initial] applying pattern '^test$' to uri '/test'
[Tue Aug 14 12:12:40.135121 2018] [rewrite:trace1] [pid 11554] mod_rewrite.c(482): [client 127.0.0.1:53326] 127.0.0.1 - - [localhost/sid#7efc776e9518][rid#7efc776710a0/initial] pass through /test
What could be missing? I wish it were possible to do rewrite rule on .htaccess

Answer 1

Here is the solution; first of all, .htaccess does not apply. According to the documentation, server config and virtual host are the context for mod_proxy that apply (.htaccess in our case doesn't make sense anyway).
The solution is to use a rewrite rule with the flag P, which causes the request to be handled by mod_proxy, and handled via a proxy request. See more here.
The virtual host should be modified as follows:
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !\.(?:css|js|jpe?g|gif|png)$ [NC]
RewriteRule ^/post/(.*)$ post.xhtml\?id=$1 [P]
ProxyPass / http://example.com:8080/
ProxyPassReverse / http:example.com:8080/