EE Entry previewing

ext.php

<?php

public function sessions_end($session)
{
	if ($session->userdata['can_access_cp'] === 'y') {
		$new_global_vars['gv_can_preview'] = TRUE;
	} else {
		$new_global_vars['gv_can_preview'] = FALSE;
	}

	$this->EE->config->_global_vars = array_merge($new_global_vars, $this->EE->config->_global_vars);
}

index.html

{exp:channel:entries
	channel="press_release"
	limit="1"
	require_entry="yes"
	status="open{if gv_can_preview}|preview{/if}"
	{gv_channel_disable_most}
}