Shopping Cart Class
*******************

The Cart Class permits items to be added to a session that stays
active while a user is browsing your site. These items can be
retrieved and displayed in a standard “shopping cart” format, allowing
the user to update the quantity or remove items from the cart.

Important:

  The Cart library is DEPRECATED and should not be used. It is
  currently only kept for backwards compatibility.

Please note that the Cart Class ONLY provides the core “cart”
functionality. It does not provide shipping, credit card
authorization, or other processing components.

* Using the Cart Class

  * Initializing the Shopping Cart Class

  * Adding an Item to The Cart

  * Adding Multiple Items to The Cart

  * Displaying the Cart

  * Updating The Cart

    * What is a Row ID?

* Class Reference


Using the Cart Class
====================


Initializing the Shopping Cart Class
------------------------------------

Important:

  The Cart class utilizes CodeIgniter’s Session Class to save the cart
  information to a database, so before using the Cart class you must
  set up a database table as indicated in the Session Documentation,
  and set the session preferences in your
  application/config/config.php file to utilize a database.

To initialize the Shopping Cart Class in your controller constructor,
use the "$this->load->library()" method:

   $this->load->library('cart');

Once loaded, the Cart object will be available using:

   $this->cart

Note:

  The Cart Class will load and initialize the Session Class
  automatically, so unless you are using sessions elsewhere in your
  application, you do not need to load the Session class.


Adding an Item to The Cart
--------------------------

To add an item to the shopping cart, simply pass an array with the
product information to the "$this->cart->insert()" method, as shown
below:

   $data = array(
           'id'      => 'sku_123ABC',
           'qty'     => 1,
           'price'   => 39.95,
           'name'    => 'T-Shirt',
           'options' => array('Size' => 'L', 'Color' => 'Red')
   );

   $this->cart->insert($data);

Important:

  The first four array indexes above (id, qty, price, and name) are
  **required**. If you omit any of them the data will not be saved to
  the cart. The fifth index (options) is optional. It is intended to
  be used in cases where your product has options associated with it.
  Use an array for options, as shown above.

The five reserved indexes are:

* **id** - Each product in your store must have a unique identifier.
  Typically this will be an “sku” or other such identifier.

* **qty** - The quantity being purchased.

* **price** - The price of the item.

* **name** - The name of the item.

* **options** - Any additional attributes that are needed to identify
  the product. These must be passed via an array.

In addition to the five indexes above, there are two reserved words:
rowid and subtotal. These are used internally by the Cart class, so
please do NOT use those words as index names when inserting data into
the cart.

Your array may contain additional data. Anything you include in your
array will be stored in the session. However, it is best to
standardize your data among all your products in order to make
displaying the information in a table easier.

   $data = array(
           'id'      => 'sku_123ABC',
           'qty'     => 1,
           'price'   => 39.95,
           'name'    => 'T-Shirt',
           'coupon'         => 'XMAS-50OFF'
   );

   $this->cart->insert($data);

The "insert()" method will return the $rowid if you successfully
insert a single item.


Adding Multiple Items to The Cart
---------------------------------

By using a multi-dimensional array, as shown below, it is possible to
add multiple products to the cart in one action. This is useful in
cases where you wish to allow people to select from among several
items on the same page.

   $data = array(
           array(
                   'id'      => 'sku_123ABC',
                   'qty'     => 1,
                   'price'   => 39.95,
                   'name'    => 'T-Shirt',
                   'options' => array('Size' => 'L', 'Color' => 'Red')
           ),
           array(
                   'id'      => 'sku_567ZYX',
                   'qty'     => 1,
                   'price'   => 9.95,
                   'name'    => 'Coffee Mug'
           ),
           array(
                   'id'      => 'sku_965QRS',
                   'qty'     => 1,
                   'price'   => 29.95,
                   'name'    => 'Shot Glass'
           )
   );

   $this->cart->insert($data);


Displaying the Cart
-------------------

To display the cart you will create a view file with code similar to
the one shown below.

Please note that this example uses the form helper.

   <?php echo form_open('path/to/controller/update/method'); ?>

   <table cellpadding="6" cellspacing="1" style="width:100%" border="0">

   <tr>
           <th>QTY</th>
           <th>Item Description</th>
           <th style="text-align:right">Item Price</th>
           <th style="text-align:right">Sub-Total</th>
   </tr>

   <?php $i = 1; ?>

   <?php foreach ($this->cart->contents() as $items): ?>

           <?php echo form_hidden($i.'[rowid]', $items['rowid']); ?>

           <tr>
                   <td><?php echo form_input(array('name' => $i.'[qty]', 'value' => $items['qty'], 'maxlength' => '3', 'size' => '5')); ?></td>
                   <td>
                           <?php echo $items['name']; ?>

                           <?php if ($this->cart->has_options($items['rowid']) == TRUE): ?>

                                   <p>
                                           <?php foreach ($this->cart->product_options($items['rowid']) as $option_name => $option_value): ?>

                                                   <strong><?php echo $option_name; ?>:</strong> <?php echo $option_value; ?><br />

                                           <?php endforeach; ?>
                                   </p>

                           <?php endif; ?>

                   </td>
                   <td style="text-align:right"><?php echo $this->cart->format_number($items['price']); ?></td>
                   <td style="text-align:right">$<?php echo $this->cart->format_number($items['subtotal']); ?></td>
           </tr>

   <?php $i++; ?>

   <?php endforeach; ?>

   <tr>
           <td colspan="2"> </td>
           <td class="right"><strong>Total</strong></td>
           <td class="right">$<?php echo $this->cart->format_number($this->cart->total()); ?></td>
   </tr>

   </table>

   <p><?php echo form_submit('', 'Update your Cart'); ?></p>


Updating The Cart
-----------------

To update the information in your cart, you must pass an array
containing the Row ID and one or more pre-defined properties to the
"$this->cart->update()" method.

Note:

  If the quantity is set to zero, the item will be removed from the
  cart.

   $data = array(
           'rowid' => 'b99ccdf16028f015540f341130b6d8ec',
           'qty'   => 3
   );

   $this->cart->update($data);

   // Or a multi-dimensional array

   $data = array(
           array(
                   'rowid'   => 'b99ccdf16028f015540f341130b6d8ec',
                   'qty'     => 3
           ),
           array(
                   'rowid'   => 'xw82g9q3r495893iajdh473990rikw23',
                   'qty'     => 4
           ),
           array(
                   'rowid'   => 'fh4kdkkkaoe30njgoe92rkdkkobec333',
                   'qty'     => 2
           )
   );

   $this->cart->update($data);

You may also update any property you have previously defined when
inserting the item such as options, price or other custom fields.

   $data = array(
           'rowid'  => 'b99ccdf16028f015540f341130b6d8ec',
           'qty'    => 1,
           'price'  => 49.95,
           'coupon' => NULL
   );

   $this->cart->update($data);


What is a Row ID?
~~~~~~~~~~~~~~~~~

The row ID is a unique identifier that is generated by the cart code
when an item is added to the cart. The reason a unique ID is created
is so that identical products with different options can be managed by
the cart.

For example, let’s say someone buys two identical t-shirts (same
product ID), but in different sizes. The product ID (and other
attributes) will be identical for both sizes because it’s the same
shirt. The only difference will be the size. The cart must therefore
have a means of identifying this difference so that the two sizes of
shirts can be managed independently. It does so by creating a unique
“row ID” based on the product ID and any options associated with it.

In nearly all cases, updating the cart will be something the user does
via the “view cart” page, so as a developer, it is unlikely that you
will ever have to concern yourself with the “row ID”, other than
making sure your “view cart” page contains this information in a
hidden form field, and making sure it gets passed to the "update()"
method when the update form is submitted. Please examine the
construction of the “view cart” page above for more information.


Class Reference
===============

class CI_Cart

   $product_id_rules = '\.a-z0-9_-'

      These are the regular expression rules that we use to validate
      the product ID - alpha-numeric, dashes, underscores, or periods
      by default

   $product_name_rules      = '\w \-\.\:'

      These are the regular expression rules that we use to validate
      the product ID and product name - alpha-numeric, dashes,
      underscores, colons or periods by default

   $product_name_safe = TRUE

      Whether or not to only allow safe product names. Default TRUE.

   insert([$items = array()])

      Parameters:
         * **$items** ("array") – Items to insert into the cart

      Returns:
         TRUE on success, FALSE on failure

      Return type:
         "bool"

      Insert items into the cart and save it to the session table.
      Returns TRUE on success and FALSE on failure.

   update([$items = array()])

      Parameters:
         * **$items** ("array") – Items to update in the cart

      Returns:
         TRUE on success, FALSE on failure

      Return type:
         "bool"

      This method permits changing the properties of a given item.
      Typically it is called from the “view cart” page if a user makes
      changes to the quantity before checkout. That array must contain
      the rowid for each item.

   remove($rowid)

      Parameters:
         * **$rowid** ("int") – ID of the item to remove from the cart

      Returns:
         TRUE on success, FALSE on failure

      Return type:
         "bool"

      Allows you to remove an item from the shopping cart by passing
      it the "$rowid".

   total()

      Returns:
         Total amount

      Return type:
         "int"

      Displays the total amount in the cart.

   total_items()

      Returns:
         Total amount of items in the cart

      Return type:
         "int"

      Displays the total number of items in the cart.

   contents([$newest_first = FALSE])

      Parameters:
         * **$newest_first** ("bool") – Whether to order the array
           with newest items first

      Returns:
         An array of cart contents

      Return type:
         "array"

      Returns an array containing everything in the cart. You can sort
      the order by which the array is returned by passing it TRUE
      where the contents will be sorted from newest to oldest,
      otherwise it is sorted from oldest to newest.

   get_item($row_id)

      Parameters:
         * **$row_id** ("int") – Row ID to retrieve

      Returns:
         Array of item data

      Return type:
         "array"

      Returns an array containing data for the item matching the
      specified row ID, or FALSE if no such item exists.

   has_options($row_id = '')

      Parameters:
         * **$row_id** ("int") – Row ID to inspect

      Returns:
         TRUE if options exist, FALSE otherwise

      Return type:
         "bool"

      Returns TRUE (boolean) if a particular row in the cart contains
      options. This method is designed to be used in a loop with
      "contents()", since you must pass the rowid to this method, as
      shown in the Displaying the Cart example above.

   product_options([$row_id = ''])

      Parameters:
         * **$row_id** ("int") – Row ID

      Returns:
         Array of product options

      Return type:
         "array"

      Returns an array of options for a particular product. This
      method is designed to be used in a loop with "contents()", since
      you must pass the rowid to this method, as shown in the
      Displaying the Cart example above.

   destroy()

      Return type:
         "void"

      Permits you to destroy the cart. This method will likely be
      called when you are finished processing the customer’s order.
