Normal Joomla operation requires a valid user to enter their...
Q: How do you test Guest functionality when your site is offline? A: You install the Offline plugin!
Normal Joomla operation requires a valid user to enter their username and password to get past the offline template page. Logging in prevents testing of guest functionality on your site. So your choice to take your site offline for development or testing actually prevents an entire segment of test cases - the guests (unregistered visitors)! For many of us, guest functionality is as important as functionality for registered users because, how are we to woo the guests unless we give them a great experience?
The Offline plugin provides a similar functionality as is found in my AdminExile extension. An administrator can set the site in offline mode inside Joomla Global Configuration, and enable this plugin to grant login-free access to the site. Browse the site as a guest (or login) - while still in offline mode.
I wrote it so I could demo custom authentication systems to a client - while remaining in offline mode. This allowed them to see the site as a guest, and login as a user would login using the various authentication methods available. Additionally, they could log in and out of the system at will - without seeing the offline page unless they ended their session (closed the browser).
Configuration is easy.
Enable the plugin
Set a key
Copy the URL displayed above the key and paste it into your browser address bar.
Edit the whitelist to add addresses you wish to immediately bypass the key requirement
Use any IPv4 IP or CIDR defined network to whitelist users from seeing the Offline page. For those not familiar, CIDR netmasks allow easy definition of entire networks in a single notation. For example, all 192.168.1.0 through 192.168.1.255 can be expressed as 192.168.1.0/24. This feature allows an administrator to whitelist one or more IP addresses or networks so that users coming from those networks will be automatically permitted to view the site with no URL authentication key. Also compatible with IPv6 addresses, and IPv6 CIDR if your server has the PHP-GMP extension installed.
When you're ready to take your site live, the plugin won't interfere. Of course, you should disable it to preserve system resources, but it takes its operating parameters from Joomla configuration itself. When Joomla is set to offline mode, the plugin will operate. When it's not in offline mode, the plugin exits as early as possible to release resources.