Custom Module Save Action not fired

Question

I am suffering from a wired problem with my Custom Module. maybe i have wrong logic in my mind or it's a problem. I created a custom module "PoProduct" to extend back-end functionality (\app\code\local\Company\Po) and i have a controller file which contains action like Save, Edit, Add etc.. Now, when i call this module into a external file and trigger save action, the controller function not called.

-------- External File Code Sample --------

<?php
require_once('app/Mage.php');
Mage::app('default');
$writeConnection = Mage::getSingleton('core/resource')->getConnection('core_write');
$readConnection = Mage::getSingleton('core/resource')->getConnection('core_read');

try {
    Mage::app()->setCurrentStore(Mage_Core_Model_App::ADMIN_STORE_ID);
    $product_Collection = Mage::getModel('catalog/product')->getCollection()->addAttributeToSelect('*')->addAttributeToFilter('status', 1);

    foreach ($product_Collection as $_product) {
        $po_product_Collection = Mage::getModel('po/poproduct')->getCollection()->addFieldToFilter('product_id', $_product->getId())->addFieldToFilter('stock_status', array("neq" => "deleted"));

        foreach ($po_product_Collection as $poproduct) {
            $poproduct->setCustomFlag("Modified");
            $poproduct->save();
        }
    }
} catch (Exception $ex) {}
?>

Here, when calling $poproduct->save(); code it's not fire PoproductController.php saveAction().

-------- Custom Module Code Sample --------

1. config.xml (\app\code\local\Company\Po\etc)

Code in config file

<config>
    <modules>
        <Company_Po>
            <version>1.0.2</version>
        </Company_Po>
    </modules>
    <admin>
        <routers>
            <po>
                <use>admin</use>
                <args>
                    <module>Company_Po</module>
                    <frontName>po</frontName>
                </args>
            </po>
        </routers>
    </admin>
    <global>
        <models>
            <po>
                <class>Company_Po_Model</class>
                <resourceModel>po_mysql4</resourceModel>
            </po>
            <po_mysql4>
                <class>Company_Po_Model_Mysql4</class>
                <entities>
                    <po>
                        <table>purchase_order_cr</table>
                    </po>
                    <poproduct>
                        <table>purchase_order_products_cr</table>
                    </poproduct>
                </entities>
            </po_mysql4>
            <po_setup>
                <setup>
                    <module>Company_Po</module>
                    <class>Company_Po_Model_Mysql4_Setup</class>
                </setup>
                <connection>
                    <use>core_setup</use>
                </connection>
            </po_setup>
        </models>
        <resources>
            <po_write>
                <connection>
                    <use>core_write</use>
                </connection>
            </po_write>
            <po_read>
                <connection>
                    <use>core_read</use>
                </connection>
            </po_read>
        </resources>
        <blocks>
            <po>
                <class>Company_Po_Block</class>
            </po> 
        </blocks>
        <helpers>
            <po>
                <class>Company_Po_Helper</class>
            </po>
        </helpers>
    </global>
</config>

2. Controller File (PoproductController.php in \app\code\local\Company\Po\controllers\Adminhtml)

   protected function _isAllowed() {
       return true;
   }
   
   protected function _initAction() {
       $this->loadLayout()
               ->_setActiveMenu('Purchase')
               ->_addBreadcrumb(Mage::helper('adminhtml')->__('Purchase Order Product'), Mage::helper('adminhtml')->__('Purchase Order Product'));
   
       return $this;
   }
   
   public function indexAction() {
       $this->_initAction()
               ->_addContent($this->getLayout()->createBlock('po/adminhtml_poproduct'))
               ->renderLayout();
   }
   
   public function saveAction() {
       if ($data = $this->getRequest()->getPost()) {            
           $model = Mage::getModel('po/poproduct');
           if ($id = $this->getRequest()->getParam('po_product_id')) {
               $model->load($id);
           }            
           $model_poproduct = Mage::getModel('po/poproduct');
           $model_poproduct->setData($data)->setId($this->getRequest()->getParam('po_product_id'));
           try {
               $model_poproduct->save();
   
               $product_id = $model_poproduct->getProductId();
               $product = Mage::getModel("catalog/product")->load($product_id);
               $product->setSomeCustomDate("XYZ");
               $product->save();
   
               Mage::getSingleton('core/session')->addSuccess(Mage::helper('po')->__('Product has been saved succesfully'));
               Mage::getSingleton('core/session')->setFormData(false);
               return;
           } catch (Exception $e) {
               Mage::getSingleton('core/session')->addError($e->getMessage());
               Mage::getSingleton('core/session')->setFormData($data);
               return;
           }
       }
   }
   

   }

Answer 1

I can see you have called $product_id in controller file. Can you debug once on this. I assume $product_id = $model_poproduct->getProductId(); is not calling product model. please call product model as per your module.

Answer 2

Here Mage::getModel('po/poproduct')->getCollection() you are calling Model and executing the save function.
You are overwriting the controller where you need to overwrite the model file.
SaveAction() will be executed from the URL.