Magento: Detect if admin is logged in in frontend pages

Question

I have created a magento extension. I want to implement access to the extension. The extension creates a page in frontend and i want only admin to access that page. So basically

Answer 1

If you're trying to make it work within the template / phtml files, and/or inside the Block's class you're going to have a hard time. Mainly because magento (aggressively) caches your PHTML blocks for performance purposes thus undoing any program flow control statements you have especially stuff related with cookie checking. I have no direct / lengthy / indepth explanation why but that's just how I've encountered it over and over again.

However, your solution should be correct, but you need to do the check within a controller's preDispatch method like so to avoid the aformentioned aggressive caches since controllers are never cached. (shown in Nick's solution in the question that you linked.):

// Ensure we're in the admin session namespace for checking the admin user..
Mage::getSingleton('core/session', array('name' => 'adminhtml'))->start();

$admin_logged_in = Mage::getSingleton('admin/session', array('name' => 'adminhtml'))->isLoggedIn();

// ..get back to the original.
Mage::getSingleton('core/session', array('name' => $this->_sessionNamespace))->start();

IF you really do need to perform the above checks inside PHTML files or named blocks, check out the following code on how to turn off block-level caching and possibly make it work. What I did before was disable caching for the footer block (in which the child block, not phtml, contains code to check
for a specific cookie)

First off, the block call (found in your local.xml, or module layout update xml, or anywhere you can do layout updates, really. I prefer breaking up my customizations into modules so definitely module layout update xml is the way to go):

      
   cache_lifetime
   cache_tags
   

And this is the newsletterpopup's block class:

And the phtml would be something like:

canRender()): ?>
   // stuff

Good luck!