Allow setting the ACTIVE_SITE via the environment.

doc/mw/multisite.rst

@@ -36,3 +36,42 @@ To setup Multisite, you must first enable it in the config/kurogo.ini file.
     ACTIVE_SITES[] = "es"
 
 This would enable only the *en* and *es* sites on this server.
+
+============================================
+Setting the active-site from the environment
+============================================
+
+There are some cases where there is a need to host multiple Kurogo sites from the same 
+webserver, but where one cannot use MultiSite mode due to its dependency on subpaths. 
+An example is serving each Kurogo site under a different host-name or domain name, 
+e.g. students.example.edu and faculty.example.edu.
+
+To accomplish this switching, Kurogo supports the specification of the ``ACTIVE_SITE`` 
+parameter via an environmental variable set by your webserver. Kurogo will only look for the ``ACTIVE_SITE`` in the environment when *not* in MultiSite mode and when the ``ACTIVE_SITE`` parameter has no value.
+
+Example ``kurogo.ini``:
+
+.. code-block:: ini
+
+	[kurogo]
+	MULTI_SITE = 0
+	ACTIVE_SITE = ""
+
+The ``ACTIVE_SITE`` environmental parameter can be set in a number of ways, but one of
+the easiest is in your Apache configuration:
+
+::
+
+	<VirtualHost *:80>
+		ServerName students.example.edu
+		DocumentRoot /var/www/kurogo/www/
+
+		SetEnv ACTIVE_SITE Students
+	</VirtualHost>
+
+	<VirtualHost *:80>
+		ServerName faculty.example.edu
+		DocumentRoot /var/www/kurogo/www/
+
+		SetEnv ACTIVE_SITE Faculty
+	</VirtualHost>

lib/Kurogo.php

@@ -734,6 +734,21 @@ private function initSite(&$path) {
             define('SITE_NAME', $site);
 
         } else {
+            // If there is no active site configured and there is one set in the environment
+            // (such as set by a VirtualHost SetEnv entry), then set the active site to the one
+            // defined in the environment.
+            try {
+                $activeSite = $siteConfig->getVar('ACTIVE_SITE', 'kurogo');
+                if (empty($activeSite)) {
+                    throw new KurogoKeyNotFoundException('ACTIVE_SITE is empty');
+                }
+            } catch (KurogoKeyNotFoundException $e) {
+                $activeSite = getenv('ACTIVE_SITE');
+                if (!empty($activeSite)) {
+                    $siteConfig->setVar('kurogo', 'ACTIVE_SITE', $activeSite, $changed);
+                }
+            }
+
         	$site = '';
             if (PHP_SAPI == 'cli') {