[Linux] Virtual host with mod_proxy on Apache2

S1. Enable mod proxy

sudo a2enmod proxy
sudo a2enmod proxy_http
sudo service apache2 restart

Add a file virtual host /etc/apache2/sites-available/example.file
- http to http

<VirtualHost *:80>
ServerAdmin your@email.com
ServerName example.com
ServerAlias www.example.com
ProxyRequests off
AllowEncodedSlashes On
<Proxy *>
Order deny,allow
Allow from all
</Proxy>
<Location />
ProxyPass http://localhost:3000/
ProxyPassReverse http://localhost:3000/
</Location>
DocumentRoot /var/www
ErrorLog ~/apache2/logs/error.log
CustomLog ~/apache2/logs/access.log combined
</VirtualHost>

- https to https

<VirtualHost 192.168.2.239:443>
    ServerName mail.example.com
    DocumentRoot /var/www
ProxyRequests off
AllowEncodedSlashes On
    <Proxy *>
        Order deny,allow
        Allow from all
    </Proxy>
    SSLEngine on
    SSLProxyEngine On
    SSLCertificateFile    /etc/ssl/certs/mhongchung_tk.crt  
    SSLCertificateKeyFile /etc/ssl/private/server.key
    ProxyRequests Off
    ProxyPreserveHost On
    ProxyPass / https://192.168.2.235/
    ProxyPassReverse / https://192.168.2.235/
</VirtualHost>

• Enable virtual host:

a2ensite example.com

• Disable virtual host

a2dissite example.com

Notes:

+ ProxyRequests off - your proxy not a open proxy that no one can use it for access to internet
+ AllowEncodedSlashes On - if don't allow, you can not access to Proxypass througt proxy if have encoded slash (%2F) (on NGINX, it allow by default)
For example: http://couchdb.chungkol.com have proxypass http://10.10.121.22:5984, and you have URL: http://couchdb.chungkol.com/check-encoded-slashes%2Fcheckdone, you can not convert to http://couchdb.chungkol.com/check-encoded-slashes/checkdone. This popular proplem in couchdb with proxy apache.