从会话购物车中删除项目数组

Question

I have an array of items kept in session cart. It gets populated in a table. each row has an index and a button to remove this particular item(items array) from $_SESSION['cart']..

This is the code I have at the moment:

 $i = 0;
 foreach($_SESSION['cart'] as $item)
{
    //Populate items in a table  ?>
<tr>
<td><center><?php echo $i; ?></center></td>
<td><center><?php echo $item['item'];?></center></td>
<td><center><?php echo '£'. $item['unitprice'];?></center></td>
<td><center><?php echo $item['quantity'];?></center></td>
    <td><center><?php echo '£'.($item['unitprice'] * $item['quantity']) ?></center></td>
<td><input type="submit" value="Remove" Onclick =  unset($_SESSION['cart'][$i]); ></td>
</tr>
<?php
 $total += ($item['unitprice'] * $item['quantity']);
$i++;
}

All I want to do is to remove one single row of data (each row contains index, item, item price, total(if there are more than one item) and remove button) from session cart. Thanks in advance..

Answer 1

The unset is correct, but PHP is executed on the servers side. So because this is a client action, you'll need to use JavaScript to pick up the action. (you could also use an old fasion form as well). I prefer to use jQuery since it allready has the built in ajax support and makes it easy. Basically, just call a function from the onClick that passes the "ID" of the element you want to delete. Then that function will make an AJAX call to another script that will take that ID and remove the element. When that script returns a success, have JavaScript delete (or hide) the element. This way the user never leaves or refreshes the page, and the script can do some extra cleanup (like database updates, session updates, validate request, etc.)

i = 0;
 foreach($_SESSION['cart'] as $item)
{
    //Populate items in a table  ?>
<tr>
<td><center><?php echo $i; ?></center></td>
<td><center><?php echo $item['item'];?></center></td>
<td><center><?php echo '£'. $item['unitprice'];?></center></td>
<td><center><?php echo $item['quantity'];?></center></td>
    <td><center><?php echo '£'.($item['unitprice'] * $item['quantity']) ?></center></td>
<td><input type="submit" value="Remove" onClick="RemoveItem(<?= $i ?>)" ></td>
</tr>
<?php
 $total += ($item['unitprice'] * $item['quantity']);
$i++;
}

Here I've changed the onClick section to use a javascript call instead. You'll notice I used the <?= tag instead of a full <?php echo . This is because as of php5 you can use the shorthand <?= to echo an expression.

In your script section you can do something like this. I use POST since it's more secure.

function RemoveItem(id) {
   $.post('script-to-remove.php',
      { ItemID: id },
      function(data) {
         if(data==='success') {
            //Remove item from DOM
         } else alert("There was an error!"); //If you want error handling
      }
   );
}

For removing items from the dom, its a bit trickier with tables since none of the cool effects will really work, such as fadeOut, slideUp, animate, etc. I would look into reformatting it with divs.

As for the php script it calls, its as simple as calling the unset. You can develop it more, so as to possibly check the validity of the request, but for now, I'm just going to do the unset.

<?php 
$ItemID = isset($_POST['ItemID'])?intval($_POST['ItemID']):-1;
if($ItemID<0) die("Invalid ID"); //Change this if you want
if(isset($_SESSION['cart'][$ItemID])) unset($_SESSION['cart'][$ItemID]);
echo 'success';
?>

Basically in this, I first check that the right parameter came in, make sure it's an integer and save it, otherwise I default it to -1. Then if the Item ID is under 0 (so definatly wrong) I tell the script to output the message and quit. Finally I check that there is a value for that ID or index as it really is, and unset it. If it makes it to the end, output the success.