CodeIgniter Tutorial

############ Static pages ############ **Note:** This tutorial assumes you've downloaded CodeIgniter and :doc:`installed the framework <../installation/index>` 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. Create a file at *application/controllers/Pages.php* with the following code. :: CodeIgniter Tutorial

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 ``$title`` variable, which we'll define later in the controller. Now, create a footer at *application/views/templates/footer.php* that includes the following code: :: © 2015 Adding logic to the controller ------------------------------ Earlier you set up a controller with a ``view()`` method. The method accepts one parameter, which is the name of the page to be loaded. The static page templates will be located in the *application/views/pages/* directory. In that directory, create two files named *home.php* and *about.php*. Within those files, type some text − anything you'd like − and save them. If you like to be particularly un-original, try "Hello World!". In order to load those pages, you'll have to check whether the requested page actually exists: :: public function view($page = 'home') { if ( ! file_exists(APPPATH.'views/pages/'.$page.'.php')) { // Whoops, we don't have a page for that! show_404(); } $data['title'] = ucfirst($page); // Capitalize the first letter $this->load->view('templates/header', $data); $this->load->view('pages/'.$page, $data); $this->load->view('templates/footer', $data); } Now, when the page does exist, it is loaded, including the header and footer, and displayed to the user. If the page doesn't exist, a "404 Page not found" error is shown. The first line in this method checks whether the page actually exists. PHP's native ``file_exists()`` function is used to check whether the file is where it's expected to be. ``show_404()`` is a built-in CodeIgniter function that renders the default error page. In the header template, the ``$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 ``$data`` array. The last thing that has to be done is loading the views in the order they should be displayed. The second parameter in the ``view()`` method is used to pass values to the view. Each value in the ``$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. Routing ------- The controller is now functioning! Point your browser to ``[your-site-url]index.php/pages/view`` to see your page. When you visit ``index.php/pages/view/about`` you'll see the about page, again including the header and footer. 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 *application/config/routes.php* and add the following two lines. Remove all other code that sets any element in the ``$route`` array. :: $route['default_controller'] = 'pages/view'; $route['(:any)'] = 'pages/view/$1'; CodeIgniter reads its routing rules from top to bottom and routes the request to the first matching rule. Each rule is a regular expression (left-side) mapped to a controller and method name separated by slashes (right-side). When a request comes in, CodeIgniter looks for the first match, and calls the appropriate controller and method, possibly with arguments. More information about routing can be found in the URI Routing :doc:`documentation <../general/routing>`. Here, the second rule in the ``$routes`` array matches **any** request using the wildcard string ``(:any)``. and passes the parameter to the ``view()`` method of the ``Pages`` class. Now visit ``index.php/about``. Did it get routed correctly to the ``view()`` method in the pages controller? Awesome!