CodeIgniter Web Application Blueprints

The common resources used in this book are discussed in upcoming sections.

We'll need a copy of CodeIgniter to start with. This book isn't really aimed at the beginner, so the chances are reasonably high that you already have a copy of CodeIgniter installed or at least know your way around enough to skip this part; however, it does make sense to briefly go through the installation of CodeIgniter so that we have something to talk about in later chapters!

First things first, go to https://ellislab.com/codeigniter/user-guide/installation/downloads.html. You'll see something similar to what is shown in the following screenshot. This is the CodeIgniter download page. At the time of writing, the current CodeIgniter version is 2.2.0; this is why the screenshot says Current version next to version 2.2.0; however, whichever version is the latest when you're reading this book is the version you want to use.

Click on the Current version link, and CodeIgniter will begin to download.

Once it's downloaded, navigate to where you have saved the file; this will be a compressed archive. Unpack it and move the contents of that file to a folder within your web root.

Specific details of routing, configuration, and database use are in each chapter (these details are specific to that particular chapter).

Twitter Bootstrap is a frontend HTML5 framework that allows anyone to easily construct reliable interfaces. At the time of writing, the version of Bootstrap used is version 3.1.1.

We will use Twitter Bootstrap throughout this book to provide the framework for all view files and templates. We will look at how to download Twitter Bootstrap and how to install it in the CodeIgniter filesystem.

Firstly, we will need to download the Twitter Bootstrap files. To do that, perform the following steps:

Once the download is finished, go to its location on your machine and unpack the archived file. Inside the unpacked file, you should see something similar to what is shown in the following structure:

bootstrap/
├── css/
│   ├── bootstrap-theme.css
│   ├── bootstrap-theme.css.map
│   ├── bootstrap-theme.min.css
│   └── bootstrap.css
│   └── bootstrap.css.map
│   └── bootstrap.min.css
├── js/
│   ├── bootstrap.js
│   └── bootstrap.min.js
└── fonts/
    ├── glyphicons-halflings-regular.eot
    ├── glyphicons-halflings-regular.svg
    ├── glyphicons-halflings-regular.ttf
    └── glyphicons-halflings-regular.woff

Move the bootstrap folder to your CodeIgniter installation so that the file hierarchy looks like the following:

/path/to/web/root/
├── application/
└── views/
    ├── common
        ├── header.php
        ├── footer.php
├── system/
├── bootstrap/
├── index.php
├── license.txt

In the preceding tree structure, the application and system directories are to do with CodeIgniter, as are the index.php and license.txt files; however, the bootstrap directory contains the contents of your Bootstrap download.

I have also indicated the location of the common header.php and footer.php files. These files are used throughout the book and act as a wrapper for every other view file.

It is possible to remove index.php from the web browser address bar when CodeIgniter is running. This can be done by following these steps:

For a long time, you had to search the Internet and download code from various places—blogs, code repositories, and so on—to find and use extensions, libraries, and other useful snippets of code for CodeIgniter. Useful installations for CodeIgniter were spread across the Internet; as such, they might have been hard to locate. Sparks acts as a single point of reference for extensions of CodeIgniter. It's simple to install and use and contains thousands of useful add-ons for CodeIgniter:

Now that Sparks is installed in your CodeIgniter instance, you can begin to install extensions and packages.

To install a package from Sparks, type the following in the command-line window:

php tools/spark install [Package Version] Spark Name

Here, Package Version is the specific version of the Spark you wish to install. You are not required to state the version and, if you it out, Sparks will download the latest version by default. Spark Name is the name of the Spark you wish to install; for example, to install example-spark (version 1.0.0), which comes with the default installation, type the following in the command-line window:

php tools/spark install -v1.0.0 example-spark

If the installation was successful, you should see something similar to the following:

user@server:/path/to/codeigniter$ php tools/spark install -v1.0.0 example-spark
[ SPARK ] Retrieving spark detail from getsparks.org
[ SPARK ] From Downtown! Retrieving spark from Mercurial repository at https://url/of/the/spark/repo
[ SPARK ] Spark installed to ./sparks/example-spark/1.0.0 - You're on fire!

Every project throughout this book will use the common header and footer files that we will create here; navigation menus will be different for each project and, as such, we will build these in the project's chapter themselves. But for now, let's look at the common header and footer files:

In each project throughout the book, we will create a specific language file containing specific language items that are relevant to that particular project. However, there are also common language elements that we won't repeat in each project (as there's no need); thus, we can have them here instead.

The language items mostly cover screen elements such as general navigation, general error and success messages, and CRUD actions (edit, delete, and so on).

With that in mind, let's go ahead and create the base language file that will serve as a template for the chapters in this book.

Create the en_admin_lang.php file at /path/to/codeigniter/application/language/english/ and add the following code to it:

// Common form elements
$lang['common_form_elements_next'] = "Next...";
$lang['common_form_elements_save'] = "Save...";
$lang['common_form_elements_cancel'] = "Cancel";
$lang['common_form_elements_go'] = "Go...";
$lang['common_form_elements_go_back'] = "Go back";
$lang['common_form_elements_submission_error'] = "There were errors with the form:";
$lang['common_form_elements_success_notifty'] = "Success:";
$lang['common_form_elements_error_notifty'] = "Error:";
$lang['common_form_elements_actions'] = "Actions";
$lang['common_form_elements_action_edit'] = "Edit";
$lang['common_form_elements_action_delete'] = "Delete";
$lang['common_form_elements_active'] = "Active";
$lang['common_form_elements_inactive'] = "Inactive";
$lang['common_form_elements_seccessful_change'] = "Your changes have been saved";
$lang['common_form_elements_seccessful_delete'] = "The item has been deleted";
$lang['common_form_elements_yes'] = "Yes";
$lang['common_form_elements_no'] = "No";
$lang['common_form_elements_to'] = "to";
$lang['common_form_elements_from'] = "from";
$lang['common_form_elements_history'] = "History";

The preceding language items are mostly for HTML forms and tables of data, such as the text for the Submit, Edit, Delete, and History buttons. Also included are general error or success messages. Feel free to add to them if you wish.

All projects in this book make use of the MY_Controller file; this is the same for all projects.

Create the MY_Controller.php file at /path/to/codeigniter/application/core/ and add the following code to it:

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class MY_Controller extends CI_Controller {

    function __construct() {
        parent::__construct();
        $this->load->helper('form');
        $this->load->helper('url');
        $this->load->helper('security');
        $this->load->helper('language');

        // Load language file
        $this->lang->load('en_admin', 'english');
    }
}

As you can see, we load helpers that are common to all projects, such as the form helper and the language helper, among others. The language file is also loaded here.

All the controllers in the project extend from this MY_Controller file rather than the default CI_Controller file.

We also are autoloading various resources such as support for database access and session management. We need to specify that we're using these resources.

Open the autoload.php file from /path/to/codeigniter/application/config/ in your text editor and find the following line:

$autoload['libraries'] = array();

Replace this line with the following:

$autoload['libraries'] = array('database', 'session');

This will ensure that the resources that are required in order to access the database and to manage sessions are always with us.

Whatever you are programming, your two main priorities are security and maintainability; this is to say that your application should be as secure as is necessary and should be written in such a way that someone else can easily program and extend on what you're doing. I can't discuss maintainability—that's up to you—but I can give you guidance on CodeIgniter and security.

However, I should say that no security is 100 percent foolproof. Even banks and security agencies that spend hundreds of millions on systems still get hacked, so what chance do we have? Well, the best we can do is try to reduce the opportunity that someone might do something that could compromise our code or database.

$system_path = 'system';

$system_path = '../system';

define('ENVIRONMENT', 'development');
/*
 *---------------------------------------------------------------
 * ERROR REPORTING
 *---------------------------------------------------------------
 *
 * Different environments will require different levels of error reporting.
 * By default development will show errors but testing and live will hide them.
 */

if (defined('ENVIRONMENT'))
{
  switch (ENVIRONMENT)
  {
    case 'development':
      error_reporting(E_ALL);
    break;

    case 'testing':
    case 'production':
      error_reporting(0);
    break;

    default:
      exit('The application environment is not set correctly.');
  }
}

define('ENVIRONMENT', 'production');

$query = "SELECT * FROM `users` WHERE user_email = ? AND user_level = ?";

$query = "SELECT * FROM `users` WHERE user_email = $user_email AND user_level = $user_level";

$this->db->query($query, array($user_email, $user_level));

Now, you will discover that we are ready to start the book and are all set to tackle each chapter.

Remember that the code for each chapter is available at the Packt website, as is the SQL for each chapter; this will save you from having to type in all this stuff.