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diff --git a/user_guide_src/source/tutorial/news_section.rst b/user_guide_src/source/tutorial/news_section.rst new file mode 100644 index 000000000..fe8e41607 --- /dev/null +++ b/user_guide_src/source/tutorial/news_section.rst @@ -0,0 +1,214 @@ +############ +News section +############ + +In the last section, we went over some basic concepts of the framework +by writing a class that includes static pages. We cleaned up the URI by +adding custom routing rules. Now it's time to introduce dynamic content +and start using a database. + +Setting up your model +--------------------- + +Instead of writing database operations right in the controller, queries +should be placed in a model, so they can easily be reused later. Models +are the place where you retrieve, insert, and update information in your +database or other data stores. They represent your data. + +Open up the application/models directory and create a new file called +news_model.php and add the following code. Make sure you've configured +your database properly as described +`here <../database/configuration.html>`_. + +:: + + <?php + class News_model extends CI_Model { + + public function __construct() + { + $this->load->database(); + } + } + +This code looks similar to the controller code that was used earlier. It +creates a new model by extending CI\_Model and loads the database +library. This will make the database class available through the +$this->db object. + +Before querying the database, a database schema has to be created. +Connect to your database and run the SQL command below. Also add some +seed records. + +:: + + CREATE TABLE news ( + id int(11) NOT NULL AUTO_INCREMENT, + title varchar(128) NOT NULL, + slug varchar(128) NOT NULL, + text text NOT NULL, + PRIMARY KEY (id), + KEY slug (slug) + ); + +Now that the database and a model have been set up, you'll need a method +to get all of our posts from our database. To do this, the database +abstraction layer that is included with CodeIgniter — `Active +Record <../database/active_record.html>`_ — is used. This makes it +possible to write your 'queries' once and make them work on `all +supported database systems <../general/requirements.html>`_. Add the +following code to your model. + +:: + + public function get_news($slug = FALSE) + { + if ($slug === FALSE) + { + $query = $this->db->get('news'); + return $query->result_array(); + } + + $query = $this->db->get_where('news', array('slug' => $slug)); + return $query->row_array(); + } + +With this code you can perform two different queries. You can get all +news records, or get a news item by its `slug <#>`_. You might have +noticed that the $slug variable wasn't sanitized before running the +query; Active Record does this for you. + +Display the news +---------------- + +Now that the queries are written, the model should be tied to the views +that are going to display the news items to the user. This could be done +in our pages controller created earlier, but for the sake of clarity, a +new "news" controller is defined. Create the new controller at +application/controllers/news.php. + +:: + + <?php + class News extends CI_Controller { + + public function __construct() + { + parent::__construct(); + $this->load->model('news_model'); + } + + public function index() + { + $data['news'] = $this->news_model->get_news(); + } + + public function view($slug) + { + $data['news'] = $this->news_model->get_news($slug); + } + } + +Looking at the code, you may see some similarity with the files we +created earlier. First, the "\_\_construct" method: it calls the +constructor of its parent class (CI\_Controller) and loads the model, so +it can be used in all other methods in this controller. + +Next, there are two methods to view all news items and one for a +specific news item. You can see that the $slug variable is passed to the +model's method in the second method. The model is using this slug to +identify the news item to be returned. + +Now the data is retrieved by the controller through our model, but +nothing is displayed yet. The next thing to do is passing this data to +the views. + +:: + + public function index() + { + $data['news'] = $this->news_model->get_news(); + $data['title'] = 'News archive'; + + $this->load->view('templates/header', $data); + $this->load->view('news/index', $data); + $this->load->view('templates/footer'); + } + +The code above gets all news records from the model and assigns it to a +variable. The value for the title is also assigned to the $data['title'] +element and all data is passed to the views. You now need to create a +view to render the news items. Create application/views/news/index.php +and add the next piece of code. + +:: + + <?php foreach ($news as $news_item): ?> + + <h2><?php echo $news_item['title'] ?></h2> + <div id="main"> + <?php echo $news_item['text'] ?> + </div> + <p><a href="news/<?php echo $news_item['slug'] ?>">View article</a></p> + + <?php endforeach ?> + +Here, each news item is looped and displayed to the user. You can see we +wrote our template in PHP mixed with HTML. If you prefer to use a +template language, you can use CodeIgniter's `Template +Parser <../libraries/parser.html>`_ class or a third party parser. + +The news overview page is now done, but a page to display individual +news items is still absent. The model created earlier is made in such +way that it can easily be used for this functionality. You only need to +add some code to the controller and create a new view. Go back to the +news controller and add the following lines to the file. + +:: + + public function view($slug) + { + $data['news_item'] = $this->news_model->get_news($slug); + + if (empty($data['news_item'])) + { + show_404(); + } + + $data['title'] = $data['news_item']['title']; + + $this->load->view('templates/header', $data); + $this->load->view('news/view', $data); + $this->load->view('templates/footer'); + } + +Instead of calling the get\_news() method without a parameter, the $slug +variable is passed, so it will return the specific news item. The only +things left to do is create the corresponding view at +application/views/news/view.php. Put the following code in this file. + +:: + + <?php + echo '<h2>'.$news_item['title'].'</h2>'; + echo $news_item['text']; + +Routing +------- + +Because of the wildcard routing rule created earlier, you need need an +extra route to view the controller that you just made. Modify your +routing file (application/config/routes.php) so it looks as follows. +This makes sure the requests reaches the news controller instead of +going directly to the pages controller. The first line routes URI's with +a slug to the view method in the news controller. + +:: + + $route['news/(:any)'] = 'news/view/$1'; + $route['news'] = 'news'; + $route['(:any)'] = 'pages/view/$1'; + $route['default_controller'] = 'pages/view'; + +Point your browser to your document root, followed by index.php/news and +watch your news page. |