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| Static pages |
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| <h1>Tutorial − Static pages</h1> |
| |
| <p class="important"><strong>Note:</strong> This tutorial assumes you've downloaded CodeIgniter and <a href="../installation/index.html">installed the framework</a> in your development environment.</p> |
| |
| <p>The first thing you're going to do is set up a <strong>controller</strong> to handle static pages. |
| A controller is simply a class that helps delegate work. It is the glue of your |
| web application.</p> |
| |
| <p>For example, when a call is made to: <code>http://example.com/news/latest/10</code> 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: <code>http://example.com/[controller-class]/[controller-method]/[arguments]</code> |
| As URL schemes become more complex, this may change. But for now, this is all we will need to know.</p> |
| |
| <p>Create a file at <dfn>application/controllers/pages.php</dfn> with the following code.</p> |
| |
| <textarea class="textarea" style="width:100%" cols="50" rows="10"> |
| <?php |
| |
| class Pages extends CI_Controller { |
| |
| public function view($page = 'home') |
| { |
| |
| } |
| } |
| </textarea> |
| |
| <p>You have created a class named "pages", with a view method that accepts one argument named <var>$page</var>. |
| The pages class is extending the CI_Controller class. |
| This means that the new pages class can access the methods and variables defined in the CI_Controller class |
| (<dfn>system/core/Controller.php</dfn>).</p> |
| |
| <p>The <strong>controller is what will become the center of every request</strong> to your web application. |
| In very technical CodeIgniter discussions, it may be referred to as the <em>super object</em>. |
| Like any php class, you refer to it within your controllers as <var>$this</var>. |
| Referring to <var>$this</var> is how you will load libraries, views, and generally |
| command the framework.</p> |
| |
| <p>Now 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.</p> |
| |
| <p>Create the header at <dfn>application/views/templates/header.php</dfn> and add the following code.</p> |
| |
| <textarea class="textarea" style="width:100%" cols="50" rows="8"> |
| <html> |
| <head> |
| <title><?php echo $title ?> - CodeIgniter 2 Tutorial</title> |
| </head> |
| <body> |
| <h1>CodeIgniter 2 Tutorial</h1> |
| |
| </textarea> |
| |
| <p>The header contains the basic HTML code that you'll want to display before loading the main view, together with a heading. |
| It will also output the <var>$title</var> variable, which we'll define later in the controller. |
| Now create a footer at <dfn>application/views/templates/footer.php</dfn> that includes the following code:</p> |
| |
| <textarea class="textarea" style="width:100%" cols="50" rows="4"> |
| <strong>&copy; 2011</strong> |
| </body> |
| </html> |
| </textarea> |
| |
| <h2>Adding logic to the controller</h2> |
| |
| <p>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 <dfn>application/views/pages/</dfn> directory.</p> |
| |
| <p>In that directory, create two files named <dfn>home.php</dfn> and <dfn>about.php</dfn>. |
| Within those files, type some text − anything you'd like − and save them. |
| If you like to be particularly un-original, try "Hello World!".</p> |
| |
| <p>In order to load those pages, you'll have to check whether the requested page actually exists:</p> |
| |
| <pre> |
| public function view($page = 'home') |
| { |
| |
| if ( ! file_exists('application/views/pages/'.$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', $data); |
| |
| } |
| </pre> |
| |
| <p>Now, when the page does exist, it is loaded, including the header and footer, and displayed to the user. If the page doesn't exist, a "404 Page not found" error is shown.</p> |
| |
| <p>The first line in this method checks whether the page actually exists. PHP's native <var>file_exists()</var> function is used to check whether the file is where it's expected to be. <var>show_404()</var> is a built-in CodeIgniter function that renders the default error page.</p> |
| |
| <p>In the header template, the <var>$title</var> 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 <var>$data</var> array.</p> |
| |
| <p>The last thing that has to be done is loading the views in the order they should be displayed. |
| The second parameter in the <var>view()</var> method is used to pass values to the view. Each value in the <var>$data</var> array is assigned to a variable with the name of its key. So the value of <var>$data['title']</var> in the controller is equivalent to $title in the view.<p> |
| |
| <h2>Routing</h2> |
| |
| <p>The controller is now functioning! Point your browser to <dfn>[your-site-url]index.php/pages/view</dfn> to see your page. When you visit <dfn>index.php/pages/view/about</dfn> you'll see the about page, again including the header and footer.</p> |
| |
| <p>Using custom routing rules, you have the power to map any URI to any controller and method, and break free from the normal convention: |
| <code>http://example.com/[controller-class]/[controller-method]/[arguments]</code></p> |
| |
| <p>Let's do that. Open the routing file located at <dfn>application/config/routes.php</dfn> and add the following two lines. Remove all other code that sets any element in the <var>$route</var> array.</p> |
| |
| <pre> |
| $route['default_controller'] = 'pages'; |
| $route['(:any)'] = 'pages/view/$1'; |
| </pre> |
| |
| <p>CodeIgniter reads its routing rules from top to bottom and routes the request to the first matching rule. Each rule is a regular expression |
| (left-side) mapped to a controller and method name separated by slashes (right-side). |
| When a request comes in, CodeIgniter looks for the first match, and calls the appropriate controller and method, possibly with arguments.</p> |
| |
| <p>More information about routing can be found in the URI Routing <a href="../general/routing.html">documentation</a>.</p> |
| |
| <p>Here, the second rule in the <var>$routes</var> array matches <strong>any</strong> request using the wildcard string <dfn>(:any)</dfn>. |
| and passes the parameter to the view() method of the pages class.</p> |
| |
| <p>Now visit <dfn>index.php/about</dfn>. Did it get routed correctly to the <var>view()</var> method |
| in the pages controller? Awesome!</p> |
| |
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