Programmatically Add Product In Cart in Magento

Adding a Product to the Cart via Querystring


For Simple Product :

$this->getUrl('checkout/cart').'add?product='.$pro_id.'&qty='.$qty.';
where : $pro_id= 'Product id' ; $qty = 'Product Quentity'

For Simple Product with Custome Option:

$this->getUrl('checkout/cart').'add?product = '.$pro_id.'&qty = '.$qty.'&options['.$pro_value.'] = '.$pro_opt_val.'
where : $pro_value= 'Product option_id';$pro_opt_val= 'Product option_type_id';

For Bundle Product :

$this->getUrl('checkout/cart').'add/product/['.$pro_id.']/?bundle_option[['.option_id.']][]=['.selection_id.']

like if bundle product's id is 2790 than :
      $_product = Mage::getModel('catalog/product')->load(2790);
      if ($_product->getTypeId() == 'bundle') 
     {
        $w = Mage::getSingleton('core/resource')->getConnection('core_write');
        $result = $w->query("select `option_id`, `selection_id` from `catalog_product_bundle_selection` where        `parent_product_id`=$id");
        $route = "checkout/cart/add";
        $params = array('product' => $id);
        while ($row = $result->fetch(PDO::FETCH_ASSOC)) {
            $params['bundle_option['. $row[option_id] .']'][] = $row['selection_id'];
       };
        header("Location: ". Mage::getUrl($route, $params));
   }

For Adding a Configurable Product to the Cart via Querystring:

http://www.your_domain.com/checkout/cart/add?product = 68&qty = 1&super_attribute[528] = 55& super_attribute[525] = 56

Here  68  is the product entity id displayed in magento admin panel.  528 and 525  is the attribute associated with this product and  55 and 56  is the selected value of that attribute. 

Another way to add product in cart :

For Simple Product :

$params = array(
    'product' => 23,
    'qty' => 2,
);
$cart = Mage::getSingleton('checkout/cart'); 
$product = new Mage_Catalog_Model_Product();
$product->load(23); 
$cart->addProduct($product, $params);
$cart->save(); 
Mage::getSingleton('checkout/session')->setCartWasUpdated(true);


For  Configurable  Product  :

$params = array(
    'product' => 23,
    'super_attribute' => array(
         528 =>55,
    ),
    'qty' => 2,
);

$cart = Mage::getSingleton('checkout/cart'); 
$product = new Mage_Catalog_Model_Product();
$product->load(23); 
$cart->addProduct($product, $params);
$cart->save(); 
Mage::getSingleton('checkout/session')->setCartWasUpdated(true);