Remove the products from category products and update or map new product to category in magento programmatically

In some time you need to remove all the products from category or unset all products from category and add or update new product to category at that time you use below code for ex:- you need to run cron job which will run every day and get a product collection of sale attribute and map that products to that category

<?php
    set_time_limit(0); 
    define('MAGENTO', '..');
    require_once MAGENTO . '/app/Mage.php';
    Mage::app();

    //Load product model collecttion filtered by sale attribute
     $proCollection = Mage::getModel('catalog/product')
                        ->getCollection()
                        ->addAttributeToSelect(array('entity_id'))
                        ->addAttributeToFilter('sale', '1');
                         
    
$writeConnection = Mage::getSingleton('core/resource')->getConnection('core_write');

        // Delete Existing Mapped product from Sale Category
        $catId=722;
        $delQuery = 'Delete from catalog_category_product where category_id ='.$catId;
        $writeConnection->query($delQuery);
        $category=Mage::getModel('catalog/category')->load($catId);
        $products = array();
        $category_products='';
        foreach ($proCollection as $product){
            if(!$category_products){
                $category_products=$product->getId().'=1&';
            }else{
                $category_products .=$product->getId().'=1&';            
            }        
        }
        //$data['category_products']='4867=1&4868;=1&4876;=1';
        parse_str($category_products, $products);    
        $category->setPostedProducts($products)->save();
        
    
        $process = Mage::getModel('index/indexer')->getProcessByCode('catalog_category_product');
        $process->reindexAll();
        
        echo 'successfully mapped the data<br>';
        exit;

?>

Download file setSale.php
http://www.magentocommerce.com/boards/viewthread/704216/

Get Todays start and end date with time in Magento

Some time we need to get collection of report or product collection of today date ,at that time need to set start date from 00:00:00 time and end with 23:59:59 for that use below code

 $todayStartOfDayDate      = Mage::app()->getLocale()->date()->setTime('00:00:00')->toString(Varien_Date::DATETIME_INTERNAL_FORMAT);
    $todayEndOfDayDate      = Mage::app()->getLocale()->date()->setTime('23:59:59')->toString(Varien_Date::DATETIME_INTERNAL_FORMAT); 

or eg:- newarrival of product collection;

 $proCollection = Mage::getModel('catalog/product')
                        ->getCollection()
                        ->addAttributeToSelect(array('entity_id'))
                        ->addAttributeToFilter('news_from_date', array('or'=> array(
                                    0 => array('date' => true, 'to' => $todayEndOfDayDate),
                                    1 => array('is' => new Zend_Db_Expr('null')))
                                ), 'left')
                                ->addAttributeToFilter('news_to_date', array('or'=> array(
                                    0 => array('date' => true, 'from' => $todayStartOfDayDate),
                                    1 => array('is' => new Zend_Db_Expr('null')))
                                ), 'left')
                                ->addAttributeToFilter(
                                    array(
                                        array('attribute' => 'news_from_date', 'is'=>new Zend_Db_Expr('not null')),
                                        array('attribute' => 'news_to_date', 'is'=>new Zend_Db_Expr('not null'))
                                        )
                                 ); 

http://www.magentocommerce.com/boards/viewthread/704170/

Cache a particular block or html in Magento

Hi, we can cache the block and also we can cache the particular HTML block code 1st time it will cache and from next time it will call from cache for eg:- in product view page your list a information in for each loop so each time it will kill your performance so 1st time cache and next time load it from cache we can cache in 2 ways 1. Cache a Block in block php add below code ex List.php

 public function __construct()
    {
        $this->addData(array(
            'cache_lifetime'    => 1800,
            'cache_tags'        => array(Mage_Catalog_Model_Product::CACHE_TAG),
            'cache_key'         => $this->getCacheKey()
        ));
    } 

    public function getCacheKey()
    {
        return $this->getRequest()->getRequestUri().$this->getCacheCurrencyCode();
    }

    //retreive current currency code
    public function getCacheCurrencyCode()
    {
        return Mage::app()->getStore()->getCurrentCurrencyCode();
    } 

2. cache a particular html block (only html code will cache it will not cache any objects ) you can do below logic even by creating new block file and can call it in product view page if you dont want to create new block for this small things you can cache the information

 <?php 
$cache = Mage::getSingleton('core/cache');
$cacheTag    = array(
Mage_Catalog_Model_Product::CACHE_TAG,
);
$currentCurrencyCode = Mage::app()->getStore()->getCurrentCurrencyCode();
$storeId = Mage::app()->getStore()->getId();
$plantationkey=str_replace(' ', '_', $plantation);
$cacheKey    = 'Origin_' .$plantationkey . $storeId .$currentCurrencyCode;
$orginhtml = $cache->load($cacheKey);

if(!empty($orginhtml)){
    echo $orginhtml;
}else{
    $theProductBlock = new Mage_Catalog_Block_Product;
    $Bestsellerproducts = Mage::getResourceModel('catalog/product_collection')
                    ->addAttributeToSelect('*')
                    ->addFieldToFilter(array(array('attribute'=>'bestseller','in'=>1)))
                    ->addAttributeToFilter('visibility', $this->visibility)
                    ->addAttributeToFilter('status', Mage_Catalog_Model_Product_Status::STATUS_ENABLED)
                    ->addCategoryFilter($category); ?>

    <?php if(count($Bestsellerproducts)):?>
    <?php 
    $orginhtml ='<ul>';
    foreach($Bestsellerproducts as $bestseller){ 
    $orginhtml .='<li>
        <h2>'.$bestseller->getName().'</h2>
        <a href="'.$bestseller->getProductUrl().'" class="product-img"><img src="'.$this->helper('catalog/image')->init($bestseller, 'small_image')->resize(229).'" width="229" height="229" alt="'.$this->stripTags($this->getImageLabel($bestseller, 'small_image'), null, true).'" title="'.$bestseller->getName().'" /></a>
        <h2 class="product-name"><a href="'.$bestseller->getProductUrl().'">'.$bestseller->getName().'</a>
        </li>';
    }
 endif; ?>    


<?php echo $orginhtml; ?>
<?php $cache->save($orginhtml, $cacheKey, $cacheTag, 3600); ?>
<?php }    ?> 

http://www.magentocommerce.com/boards/viewthread/700444/