<head> section) and including the app’s common components, such as a header and footer.Rather than repeating the code for these startup chores in every file, you should create two files — one for the back end initialization and one for the front end’s common code — and then include the files as you begin each web app task.
Creating the back-end initialization file
When performing any task, a typical web app must first run through a number of back-end chores, including the following:- Setting the error reporting level
- Starting a session for the current user, if one hasn’t been started already
- Creating a token for the session
- Including common files, such as a file of constants used throughout the app
- Connecting to the database, if the app uses server data
This code cranks up the error reporting to 11 for the purposes of debugging, starts a new session, creates a session token (if needed), includes the constants file (which contains the database credentials), and then connects to the database and creates a// Start a session session_start();
// Have we not created a token for this session, // or has the token expired? if (!isset($_SESSION['token']) || time() > $_SESSION['token_expires']){ $_SESSION['token'] = bin2hex(openssl_random_pseudo_bytes(16)); $_SESSION['token_expires'] = time() + 900; $_SESSION['log_id'] = 1; }
// Include the app constants include_once 'constants.php';
// Connect to the database $mysqli = new MySQLi(HOST, USER, PASSWORD, DATABASE);
// Check for an error if($mysqli->connect_error) { echo 'Connection Failed! Error #' . $mysqli->connect_errno . ': ' . $mysqli->connect_error; exit(0); } ?>
MySQLi object. Note, too, that $_SESSION['log_id'] was set to 1, but this is temporary.
You want to use error_reporting(E_ALL | E_STRICT) when you’re developing your web app because you want the PHP processor to let you know when something’s amiss, either as an error (E_ALL) or as non-standard PHP code (E_STRICT). However, you certainly don't want your app’s users to see these errors or warnings, so when you’re ready for your web app to go live, edit initialization.php to follow this statement:
error_reporting(E_ALL | E_STRICT)with these statements:
ini_set('display_errors', 0);
ini_set('log_errors', 1);
ini_set('error_log', '../private/logs/error_log');
These statements configure PHP to not display errors onscreen, but to log them to a file, the name and path of which is specified in the final statement.
Creating the front-end common files
Each page of your web app has a common structure. For example, the top part of each page includes the following elements:- The
DOCTYPEand the<html>tag - The head element, including the
<meta>tags, page title, CSS<link>tags, and JavaScript<script>tags - An event handler for jQuery's
readyevent - The
<body>tag - Common page elements, such as the
<header>,<nav>, and<main>tags
public/common/top.php:
In this code, note that the page title is given by the following inline PHP: The idea here is that each page will set theFootPower! | <?php echo $page_title ?>
$page_title variable just before including top.php, which enables you to define a custom title for each page. For example, the home page might do this:
Note that this same title also gets inserted in the page header element, within the <h1> tag.Most web apps also include a sidebar — defined by an <aside> tag — that includes info common to all pages, such as a description of the app, instructions for using the app, the latest app news, or a newsletter sign-up form. For this sidebar, create a separate file called, say, public\common\sidebar.php and include your code:
</main> closing tag, a footer, and the </body> and </html> closing tags. For this code, create a separate file called, say, public\common\bottom.php and add your code:
The footer uses the PHP statement
echo date('Y') to output the current year for the Copyright notice. This file also adds references to the app's two external JavaScript files: data.js and user.js. Adding these at the bottom of the page (instead of the usual place in the page's head section) ensures that your JavaScript code can work with the elements added to the page on the fly.
Building the app home page
With the initialization files in place, it’s time to build the skeleton for the app’s home page. At the moment, this page is nothing but PHP:="code"> Main app content goes hereSave this file as
index.php in the web root directory.