Magento 1.7 – Persistent Shopping Cart and session.gc_maxlifetime

Persistent shopping cart isn't necessarily just the synchronization of the shopping cart experience, it is the persistence of the logged in session, meaning you don't get logged out after some period of inactivity. This always-logged-in experience (popularized by Amazon) gives the customer personalization and allows the store owner to merchandise in a more targeted fashion.

When you are actively logged in as a registered customer you utilize the same cart session and that session is shared by all devices as the records are stored in the database and are refreshed to your logged in sessions on each page load.

Update:

Your original question was 'why does my cart persist across devices even without persistent cart turned on' - which is the question I answered. Perhaps I over-simplified the feature.

So, hopefully this is to your satisfaction - having performed a code review on persistent cart in 1.8 Alpha this is the functionality introduced:

• Adds "not [username]?" to the welcome statement, before logout link
• Adds a 'remember me' checkbox to registration forms
• Provides its own customer registration forms
• Provides its own session object
• Observes login / logout
• Provides a shim between purchase and account access if the persistent login session is being used (to prevent unauthorized purchases, for instance)
• Provides emulation of quotes, customer objects to piggyback data into the regular customer session
• Provides a synchronizePersistentOnLogout/Login method that seems to log all browser sessions out if the customer session logs out of one browser (would appreciate some feedback here)

All of the above is to facilitate a non-expiring customer session that gives the store manager the ability to merchandise to the customer differently based on customer segment. With Enterprise Edition Banners, Customer Segments, Promotions one could provide a completely different site experience, based on customer segments alone (geographic location, items/categories purchased, total $ spend in a calendar year, etc.) that would persist to all devices.

@Marius while you would expect that to be logical in reality there is an edge case where the guest checkout option is disabled.

Replication

• Logged in customer adds items to basket
• Customer closes browsers
• Website session times out kill var/session directory
• Customer opens browser adds items to basket as guest.
• Guest checkout it hidden.

Cause

An event called checkout_allow_guest is fired by Mage_Checkout_Helper_Data::isAllowedGuestCheckout()

This then observed by Mage_Persistent_Model_Observer::disableGuestCheckout() which disables the option to use guest checkout.

The cause of which is that the session is loaded by Mage_Persistent_Helper_Session::isPersistent() with the value of the persistence cookie:

    if (is_null($key)) {
        $key = Mage::getSingleton('core/cookie')->get(Mage_Persistent_Model_Session::COOKIE_NAME);
    }

Fix - Disabled event observer

You will need to create a new module with two files.

app/code/local/JZah/AllowPersistentGuestCheckout/etc/config.xml:

<?xml version="1.0"?>
<config>
    <modules>
        <JZah_AllowPersistentGuestCheckout>
            <version>0.1.0</version>
        </JZah_AllowPersistentGuestCheckout>
    </modules>
    <frontend>
        <events>
            <checkout_allow_guest>
                <observers>
                    <persistent>
                        <type>disabled</type>
                    </persistent>
                </observers>
            </checkout_allow_guest>
        </events>
    </frontend>
</config>

app/etc/modules/JZah_AllowPersistentGuestCheckout.xml:

<?xml version="1.0"?>
<config>
    <modules>
        <JZah_AllowPersistentGuestCheckout>
            <active>true</active>
            <codePool>local</codePool>
            <depends>
                <Enterprise_Persistent/>
            </depends>
        </JZah_AllowPersistentGuestCheckout>
    </modules>
</config>

Created for Magento EE 1.14.1.0