Take
a look at the code below, it's the code for index.php, the main page
Source code : index.php
<?php
require_once 'library/config.php';
require_once 'library/category-functions.php';
require_once 'library/product-functions.php';
require_once 'library/cart-functions.php';
$_SESSION['shop_return_url'] = $_SERVER['REQUEST_URI'];
$catId = (isset($_GET['c']) && $_GET['c'] != '1') ?
$_GET['c'] : 0;
$pdId = (isset($_GET['p']) && $_GET['p'] != '') ?
$_GET['p'] : 0;
// ... more code here
?>
First we load the required libraries. The config.php file contain all kind of initialization like setting the database connection,
defining constants, and it also load the common libraries. I won't explain
the detail, just take a look at the file and i'm sure you will understand
what it does.
Next is category-functions.php.
This file contain the several functions, they are :
- formatCategories()
This function is used by include/leftNav.php.
It's job is to generate the category list where the currently selected category
will expand and show the children categories ( if it have any ).
- getCategoryList()
Get a list of first level categories ( i.e. the parent id is zero )
- getChildCategories()
Get all children categories
- fetchCategories()
Get all categories ( first and second level )
After finish loading the libraries we set a session variable $_SESSION['shop_return_url'].
The value for this session is the url of the page that we currently
see. This variable is used by the shopping cart. When you click
on the 'Continue Shopping' button it will redirect to the url
pointed by this session variable.
Next step is checking the existence of $_GET['c'] ( category id ) and $_GET['p'] ( product
id ). If none exist in the query string we show the category list ( categoryList.php ). If only the category id exist then we show all product
in that category ( productList.php ). And if the product id also exist we show that product information ( productDetail.php ).
Source code : index.php
<?php
// ... previous code
include 'header.php';
?>
<table width="780" border="1" align="center"
cellpadding="0" cellspacing="0">
<tr>
<td colspan="3">
<?php include 'top.php'; ?>
</td>
</tr>
<tr valign="top">
<td width="150" height="400" id="leftnav">
<?php
include 'leftNav.php';
?>
</td>
<td>
<?php
if ($pdId) {
include 'productDetail.php';
} else if ($catId) {
include 'productList.php';
} else {
include 'categoryList.php';
}
?>
</td>
<td width="130" align="center"><?php include
'miniCart.php'; ?></td>
</tr>
</table>
<?php
include 'footer.php';
?>
As you can see from the above code, the main page doesn't do much.
It "out sourced" almost everything. The header, navigation,
content, mini cart and the footer. Of course this is a good thing
because if we need to modify some part ( like the left navigation
) we can do it wit less risk of messing with the other part.
Now, lets take a deeper look at the header file. One important usage of this file is to set the page title. You may have noticed it that when you're browsing the categories and products the page title change accordingly.
Setting up a descriptive page title is especially important when you consider SEO ( search engine optimization ).
You see, search engine put heavy emphasize on the page title so we better get this one thing right.
Here how it works. By default we set the page title as "My Online Shop" but if a product id is detected in the query string we search the database to find the name of the product. Then we use the product's name as the page title.
If we can't find any product id in the query string we do another test to see if there's a category id in there. If we found one we fetch the category name from the database and use it as the page title.
Here is the code :
Source : include/header.php
<?php
if (!defined('WEB_ROOT')) {
exit;
}
// set the default page title
$pageTitle = 'My Online Shop';
if (isset($_GET['p']) && (int)$_GET['p'] > 0) {
$pdId = (int)$_GET['p'];
$sql = "SELECT pd_name
FROM tbl_product
WHERE pd_id = $pdId";
$result = dbQuery($sql);
$row = dbFetchAssoc($result);
$pageTitle = $row['pd_name'];
} else if (isset($_GET['c']) && (int)$_GET['c'] > 0) {
$catId = (int)$_GET['c'];
$sql = "SELECT cat_name
FROM tbl_category
WHERE cat_id = $catId";
$result = dbQuery($sql);
$row = dbFetchAssoc($result);
$pageTitle = $row['cat_name'];
}
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title><?php echo $pageTitle; ?></title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<link href="include/shop.css" rel="stylesheet" type="text/css">
<script language="JavaScript" type="text/javascript" src="library/common.js"></script>
</head>
<body>
Next we explore further about the category browsing ( that navigation links on the left section of the page ).
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