WordPress / Apache / Reverse Proxy

apache.conf

<VirtualHost ...>
	...
	# Reverse Proxy
	ProxyRequests Off
	#ProxyPreserveHost On
	RequestHeader set X-Forwarded-Proto "https"
	ProxyPass /blog http://blog.example.org/blog
	ProxyPassReverse /blog http://blog.example.org/blog
	...
</VirtualHost>

wp-config.php

/**
 * Reverse Proxy
 */
define('WP_HOME', 'https://www.example.org/blog');
define('WP_SITEURL', 'https://www.example.org/blog'); 

if(isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https') {
	$_SERVER['HTTPS'] = 'on';
	$_SERVER['REQUEST_SCHEME'] = 'https';
}

if ( ! empty($_SERVER['HTTP_X_FORWARDED_FOR']) ) {
	$_SERVER['REMOTE_ADDR'] = $_SERVER['HTTP_X_FORWARDED_FOR'];
}

if ( ! empty( $_SERVER['HTTP_X_FORWARDED_HOST'] ) ) {
	$_SERVER['HTTP_HOST'] = $_SERVER['HTTP_X_FORWARDED_HOST'];
}