Static pages

Note: This tutorial assumes you’ve downloaded CodeIgniter and installed the framework in your development environment.

The first thing you’re going to do is set up a controller to handle static pages. A controller is simply a class that helps delegate work. It is the glue of your web application.

For example, when a call is made to:

http://example.com/news/latest/10

We might imagine that there is a controller named “news”. The method being called on news would be “latest”. The news method’s job could be to grab 10 news items, and render them on the page. Very often in MVC, you’ll see URL patterns that match:

http://example.com/[controller-class]/[controller-method]/[arguments]

As URL schemes become more complex, this may change. But for now, this is all we will need to know.

Let’s make our first controller

Create a file at app/Controllers/Pages.php with the following code.

<?php namespace App\Controllers;
use CodeIgniter\Controller;

    class Pages extends Controller {

    public function index()
    {
        return view('welcome_message');
    }

    public function showme($page = 'home')
    {
    }
    }

You have created a class named Pages, with a showme method that accepts one argument named $page. It also has an index() method, the same as the default controller found in app/Controllers/Home.php; that method displays the CodeIgniter welcome page.

The Pages class is extending the CodeIgniter\Controller class. This means that the new Pages class can access the methods and variables defined in the CodeIgniter\Controller class (system/Controller.php).

The controller is what will become the center of every request to your web application. Like any php class, you refer to it within your controllers as $this.

Now that you’ve created your first method, it’s time to make some basic page templates. We will be creating two “views” (page templates) that act as our page footer and header.

Create the header at app/Views/templates/header.php and add the following code:

<!doctype html>
<html>
<head>
        <title>CodeIgniter Tutorial</title>
</head>
<body>

        <h1><?= $title; ?></h1>

The header contains the basic HTML code that you’ll want to display before loading the main view, together with a heading. It will also output the $title variable, which we’ll define later in the controller. Now, create a footer at app/Views/templates/footer.php that includes the following code:

        <em>&copy; 2019</em>
</body>
</html>

Adding logic to the controller

Earlier you set up a controller with a showme() method. The method accepts one parameter, which is the name of the page to be loaded. The static page bodies will be located in the app/Views/pages/ directory.

In that directory, create two files named home.php and about.php. Within those files, type some text − anything you’d like − and save them. If you like to be particularly un-original, try “Hello World!”.

In order to load those pages, you’ll have to check whether the requested page actually exists. This will be the body of the showme() method in the Pages controller created above:

public function showme($page = 'home')
{
        if ( ! is_file(APPPATH.'/Views/pages/'.$page.'.php'))
        {
            // Whoops, we don't have a page for that!
            throw new \CodeIgniter\Exceptions\PageNotFoundException($page);
        }

        $data['title'] = ucfirst($page); // Capitalize the first letter

        echo view('templates/header', $data);
        echo view('pages/'.$page, $data);
        echo view('templates/footer', $data);
}

Now, when the requested page does exist, it is loaded, including the header and footer, and displayed to the user. If the requested page doesn’t exist, a “404 Page not found” error is shown.

The first line in this method checks whether the page actually exists. PHP’s native is_file() function is used to check whether the file is where it’s expected to be. The PageNotFoundException is a CodeIgniter exception that causes the default error page to show.

In the header template, the $title variable was used to customize the page title. The value of title is defined in this method, but instead of assigning the value to a variable, it is assigned to the title element in the $data array.

The last thing that has to be done is loading the views in the order they should be displayed. The view() method built-in to CodeIgniter will be used to do this. The second parameter in the view() method is used to pass values to the view. Each value in the $data array is assigned to a variable with the name of its key. So the value of $data['title'] in the controller is equivalent to $title in the view.

Note

Any files and directory names passed into the view() function MUST match the case of the actual directory and file itself or the system will throw errors on case-sensitive platforms.

Running the App

Ready to test? You cannot run the app using PHP’s built-in server, since it will not properly process the .htaccess rules that are provided in public, and which eliminate the need to specify “index.php/” as part of a URL. CodeIgniter has its own command that you can use though.

From the command line, at the root of your project:

php spark serve

will start a web server, accessible on port 8080. If you set the location field in your browser to localhost:8080, you should see the CodeIgniter welcome page.

You can now try several URLs in the browser location field, to see what the Pages controller you made above produces...

  • localhost:8080/pages will show the results from the index method inside our Pages controller, which is to display the CodeIgniter “welcome” page, because “index” is the default controller method
  • localhost:8080/pages/index will also show the CodeIgniter “welcome” page, because we explicitly asked for the “index” method
  • localhost:8080/pages/showme will show the “home” page that you made above, because it is the default “page” parameter to the showme() method.
  • localhost:8080/pages/showme/home will also show the “home” page that you made above, because we explicitly asked for it
  • localhost:8080/pages/showme/about will show the “about” page that you made above, because we explicitly asked for it
  • localhost:8080/pages/showme/shop will show a “404 - File Not Found” error page, because there is no app/Views/pages/shop.php

Routing

The controller is now functioning!

Using custom routing rules, you have the power to map any URI to any controller and method, and break free from the normal convention: http://example.com/[controller-class]/[controller-method]/[arguments]

Let’s do that. Open the routing file located at app/Config/Routes.php and look for the “Route Definitions” section of the configuration file.

The only uncommented line there to start with should be::

$routes->get('/', 'Home::index');

This directive says that any incoming request without any content specified should be handled by the index method inside the Home controller.

Add the following line, after the route directive for ‘/’.

$routes->get('(:any)', 'Pages::showme/$1');

CodeIgniter reads its routing rules from top to bottom and routes the request to the first matching rule. Each rule is a regular expression (left-side) mapped to a controller and method name separated by slashes (right-side). When a request comes in, CodeIgniter looks for the first match, and calls the appropriate controller and method, possibly with arguments.

More information about routing can be found in the URI Routing documentation.

Here, the second rule in the $routes array matches any request using the wildcard string (:any). and passes the parameter to the view() method of the Pages class.

Now visit home. Did it get routed correctly to the showme() method in the pages controller? Awesome!

You should see something like the following:

../_images/tutorial1.png