How to set validation on checkout with minimum qty purchase magento

How to set validation on checkout with minimum qty magento

Put below code in your module/any module config.xml file after <models> block

<global>

    <events>

        <controller_action_predispatch_checkout_onepage_index>

            <observers>

                <spirit_cms_validate_checkout>

                    <class>Setblue_Banner_Model_Observer</class>

                    <method>validateCheckout</method>

                </spirit_cms_validate_checkout>

            </observers>

        </controller_action_predispatch_checkout_onepage_index>

    </events>

</global>

Next we need to create observer file to read this code. Create Observer.php in /yourmodule/Model/Observer.php and put the below code :

public function validateCheckout($observer)

{

    // Ensure we only observe once. $oObserver

    if( Mage::registry( 'restrict_checkout_flag' ) )

    {

        return $this;

    }

    else

    {

        $oQuote = Mage::getSingleton( 'checkout/cart' )->getQuote();

        $oCartItems = $oQuote->getAllItems();

        $iTotalAmount = $oQuote->getGrandTotal();

        $iGroupId = $oQuote->getCustomerGroupId();

        $iTotalQty = 0;

        foreach( $oCartItems as $oCartItem )

        {

            $iTotalQty = $iTotalQty + $oCartItem->getQty();

        }

        if($iGroupId == '2'){

            if( $iTotalQty < 15 )

            {

                $oSession = Mage::getSingleton( 'checkout/session' );

                $oSession->addError( 'Please add at least 15 items to your cart.' );

                Mage::app()->getResponse()->setRedirect( Mage::getUrl( 'checkout/cart' ) );

            }

            Mage::register( 'restrict_checkout_flag', 1, TRUE );

        }

     

    }

}