Shopping Cart for CodeIgniter

Despite much Googling, I haven’t been able to find a ready made shopping cart for the CodeIgniter PHP framework. Unfortunately one of my current projects requires such a thing, so I decided to roll my own. Starting from the code here: http://v3.thewatchmakerproject.com/journal/276/building-a-simple-php-shopping-cart, I made a few changes to fit the CodeIgniter way of doing things.

The revised version looks like this:

1. <?php
2. // Based on http://v3.thewatchmakerproject.com/journal/276/building-a-simple-php-shopping-cart
3. class Cart extends Controller {
4. function Cart()
5. {
6. parent::Controller();
7. $this->load->library('session');
8. $this->load->helper('url');
9. }
10. function index()
11. {
12. $cart = $this->session->userdata('cart');
13. if ($cart) {
14. $items = explode(',',$cart);
15. $contents = array();
16. foreach ($items as $item) {
17. $contents[$item] = (isset($contents[$item])) ? $contents[$item] + 1 : 1;
18. }
19. }
20. if ($contents)
21. {
22. $id_list = '';
23. foreach(array_keys($contents) as $val)
24. $id_list .=  $this->db->escape($val) .',';
25. $id_list = substr($id_list,0,len($id_list) - 1);
26. $query_string = "SELECT * FROM stock_table WHERE id IN(".$id_list.")";
27. $query = $this->db->query($query_string);
28. f ($query->num_rows() > 0)
29. {
30. $basket = array();
31. foreach ($query->result() as $row)
32. {
33. $basket[] = array('id' => $row->id, 'caption' => $row->caption, 'price' => $row->price,
'qty' => $contents[$row->id], 'total' => $contents[$row->id] * $row->price);
34. }
35. }
36. }
37. $data = array();
38. if ($basket)
39. {
40. $data['basket'] = $basket;
41. $grand_total = 0;
42. foreach($basket as $item)
43. $grand_total += $item[total];
44. $data['grand_total'] = sprintf("%01.2f", $grand_total);
45. }
46. else
47. $data['grand_total'] = sprintf("%01.2f", 0);
48. $data['page'] = 'cart_view';
49. $data['title'] = "Your basket";
50. $this->load->view('template/container',$data);
51. }
52. function add_item($item_id='')
53. {
54. $cart = $this->session->userdata('cart');
55. if ($cart) {
56. $cart .= ','.$item_id;
57. } else {
58. $cart = $item_id;
59. }
60. $this->session->set_userdata(array('cart' =>
61. $cart));
62. redirect('/cart/', 'refresh');
63. }
64. function delete_item($item_id='')
65. {
66. $cart = $this->session->userdata('cart');
67. if ($cart) {
68. $items = explode(',',$cart);
69. $newcart = '';
70. foreach ($items as $item) {
71. if ($item_id != $item) {
72. if ($newcart != '') {
73. $newcart .= ','.$item;
74. } else {
75. $newcart = $item;
76. }
77. }
78. }
79. $cart = $newcart;
80. }
81. $this->session->set_userdata(array('cart' =>
82. $cart));
83. redirect('/cart/', 'refresh');
84. }
85. function delete_all()
86. {
87. $this->session->unset_userdata('cart');
88. redirect('/cart/', 'refresh');
89. }
90. function update_cart()
91. {
92. if ($cart) {
93. $newcart = '';
94. foreach ($_POST as $key=>$value) {
95. if (stristr($key,'qty')) {
96. $id = str_replace('qty','',$key);
97. $items = ($newcart != '') ? explode(',',$newcart) : explode(',',$cart);
98. $newcart = '';
99. foreach ($items as $item) {
100. if ($item_id != $item) {
101. if ($newcart != '') {
102. $newcart .= ','.$item;
103. } else {
104. $newcart = $item;
105. }
106. }
107. }
108. for ($i=1;$i<=$value;$i++) {
109. if ($newcart != '') {
110. $newcart .= ','.$id;
111. } else {
112. $newcart = $id;
113. }
114. }
115. }
116. }
117. }
118. $this->session->set_userdata(array('cart' =>
119. $newcart));
120. redirect('/cart/', 'refresh');
121. }
122. function checkout()
123. {
124. }
125. }

The associated view looks like this:

1. <p>Basket Total: &pound;<?=$grand_total?></p>
2. <?php
3. if (isset($basket))
4. {
5. ?>
6. <form method="post" id="cart-form" action="<?=site_url().'update_cart'?>">
7. <table>
8. <tr><td>ID:</td><td>Desc:</td><td>Price:</td><td>Quantity:</td><td>Total:</td><td>Delete?</td></tr>
9. <?php
10. foreach ($basket as $val)
11. {
12. ?>
13. <tr><td><?=$val['id']?></td><td><?=$val['caption']?></td><td><?=$val['price']?></td>
<td><input type="text" name="qty'<?=$val['id']?>'" value="<?=$val['qty']?>" size="3" maxlength="3" /></td>
<td><?=$val['total']?></td><td><a href="<?=site_url().'delete_item/'.$val['id']?>">[x]</a></td></tr>
14. <?php
15. }
16. ?>
17. </table>
18. <input type="submit" name="submit" value="Update Cart" />
19. </form>
20. <p><a href="<?=site_url().'delete_all'?>">Empty Cart</a></p>
21. <p><a href="<?=site_url().'checkout'?>">Checkout</a></p>
22. <?php
23. }
24. else
25. {
26. ?>
27. <p>Your shopping basket is empty.</p>
28. <?php
29. }
30. ?>

The code also assumes a database “stock_table” with the following structure:

1. --
2. -- Table structure for table `stock_table`
3. --
4. CREATE TABLE IF NOT EXISTS `stock_table` (
5. `id` int(10) unsigned NOT NULL auto_increment,
6. `caption` varchar(20) NOT NULL,
7. `quantity` int(10) NOT NULL default '0',
8. `price` float NOT NULL,
9. PRIMARY KEY  (`id`)
10. ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;

This code has yet to be put to the test in a production environment, so use it entirely at your own risk. You will also notice that the checkout function has not been completed. This is a project for another day, and it’s worth looking at the CodeIgniter PayPal library http://codeigniter.com/wiki/PayPal_Lib/ to help you.