how to get current url in php

<?php echo $_SERVER['HTTP_REFERER'];?>

Discount per product in magento

steps for apply discount per product by percent & also create by flat amount

1.step create attribute 'discount' data-type texfield
 create another attribute 'appludiscount' data-type yes/no  default value yes

2.assign attribute in attribute set's price tab

3.add following code in catalog/product/view.phtml file just after
product name
   
    <?php $discount = $_product['discount']; ?>
        <?php if($discount !=""){?>
            <div class="product-discount">
            <?php echo $discount."% Discount"; ?>
            </div>
        <?php }?>

4.add following code in checkout/cart/item/default.phtml file after line no 41
<?php
$custom = Mage::getModel('catalog/product')->load($_item->getProductId());
$discount= $custom['discount']; ?>
<?php if($discount !=""){?>
<div class="discount"> <?php if($custom->getAttributeText('applydiscount') == "No")
{echo Flat." ".$discount." ". Discount; }
else
{
    echo $discount."% Discount";}?></div>
<?php }?>

5. now create observer file for it so create module
app/code/local/plumtree/Discount/model/observer.php file
<?php

class Plumtree_Discount_Model_Observer
{
   
    public function modifyPrice(Varien_Event_Observer $observer)
    {
       
       $item = $observer->getQuoteItem();
    if ($item->getParentItem()) {
        $item = $item->getParentItem();
        //echo "<pre>";
        //print_r($item->getData());exit;
    }

   
    $pid= $item->getProductId();
   $product = Mage::getModel('catalog/product')->load($pid);
   $productData  = $product->getData();
    $discount = $productData['discount'];
                   /* flat ammount Discount code starts here*/
    if( $product->getAttributeText('applydiscount') == "No"){
        $specialprice = $product->getFinalPrice();
        $new_price = $specialprice - $discount;
               if ($new_price > 0) {
        $item->setCustomPrice($new_price);
        $item->setOriginalCustomPrice($new_price);
        $item->getProduct()->setIsSuperMode(true);
            }
        }
       
         /* flat ammount Discount code ends here*/
       
          /* flat percent Discount code starts here*/
        else{
            $specialprice = $product->getFinalPrice();
            $new_price = ($specialprice*(100-$discount))/100;
                   if ($new_price > 0) {
         $item->setCustomPrice($new_price);
         $item->setOriginalCustomPrice($new_price);
         $item->getProduct()->setIsSuperMode(true);
              }
            }
           
             /* flat percent Discount code ends here*/
}
}

6.create app/code/local/plumtree/Discount/etc/config.xml

<?xml version="1.0"?>
<config>
    <modules>
        <Plumtree_Discount>
            <version>0.1.0</version>
        </Plumtree_Discount>
    </modules>
       <frontend>
         <events>
            <checkout_cart_product_add_after>
                <observers>
                   <Plumtree_Discount_Model_Observer>
                      <type>singleton</type>
                      <class>Plumtree_Discount_Model_Observer</class>
                      <method>modifyPrice</method>
                   </Plumtree_Discount_Model_Observer>
               </observers>
            </checkout_cart_product_add_after>
        </events>
      </frontend>
</config>
enjoy the code.

how to remove null data from additionali information table in product detail page in magento

By default if any value is not assigned to product data it retrive no in additionali information
check in chair dimension has no value

so go to \app\design\frontend\pro\weldingmart\template\catalog\product\view\attributes.phtml
add one if condition before <tr >starts like
  <?php if($_product[$_data['code']] != ""){?>
             <tr>
                <th class="label"><?php echo $this->htmlEscape($this->__($_data['label'])) ?></th>
                <td class="data"><?php echo $_helper->productAttribute($_product, $_data['value'], $_data['code']) ?></td>
            </tr>
            <?php }?>