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| -rw-r--r-- | user_guide_src/source/index.rst | 3 | ||||
| -rw-r--r-- | user_guide_src/source/tutorial/conclusion.rst | 26 | ||||
| -rw-r--r-- | user_guide_src/source/tutorial/create_news_items.rst | 153 | ||||
| -rw-r--r-- | user_guide_src/source/tutorial/index.rst | 47 | ||||
| -rw-r--r-- | user_guide_src/source/tutorial/news_section.rst | 214 | ||||
| -rw-r--r-- | user_guide_src/source/tutorial/static_pages.rst | 170 |
6 files changed, 612 insertions, 1 deletions
diff --git a/user_guide_src/source/index.rst b/user_guide_src/source/index.rst index e53182550..0e6bc5003 100644 --- a/user_guide_src/source/index.rst +++ b/user_guide_src/source/index.rst @@ -42,4 +42,5 @@ CodeIgniter is right for you if: libraries/index database/index helpers/index - documentation/index
\ No newline at end of file + documentation/index + tutorial/index
\ No newline at end of file diff --git a/user_guide_src/source/tutorial/conclusion.rst b/user_guide_src/source/tutorial/conclusion.rst new file mode 100644 index 000000000..48fbdcc8a --- /dev/null +++ b/user_guide_src/source/tutorial/conclusion.rst @@ -0,0 +1,26 @@ +########## +Conclusion +########## + +This tutorial did not cover all of the things you might expect of a +full-fledged content management system, but it introduced you to the +more important topics of routing, writing controllers, and models. We +hope this tutorial gave you an insight into some of CodeIgniter's basic +design patterns, which you can expand upon. + +Now that you've completed this tutorial, we recommend you check out the +rest of the documentation. CodeIgniter is often praised because of its +comprehensive documentation. Use this to your advantage and read the +"Introduction" and "General Topics" sections thoroughly. You should read +the class and helper references when needed. + +Every intermediate PHP programmer should be able to get the hang of +CodeIgniter within a few days. + +If you still have questions about the framework or your own CodeIgniter +code, you can: + +- Check out our `forums <http://codeigniter.com/forums>`_ +- Visit our `IRC chatroom <http://codeigniter.com/wiki/IRC>`_ +- Explore the `Wiki <http://codeigniter.com/wiki/>`_ + diff --git a/user_guide_src/source/tutorial/create_news_items.rst b/user_guide_src/source/tutorial/create_news_items.rst new file mode 100644 index 000000000..003b94bd8 --- /dev/null +++ b/user_guide_src/source/tutorial/create_news_items.rst @@ -0,0 +1,153 @@ +################# +Create news items +################# + +You now know how you can read data from a database using CodeIgnite, but +you haven't written any information to the database yet. In this section +you'll expand your news controller and model created earlier to include +this functionality. + +Create a form +------------- + +To input data into the database you need to create a form where you can +input the information to be stored. This means you'll be needing a form +with two fields, one for the title and one for the text. You'll derive +the slug from our title in the model. Create the new view at +application/views/news/create.php. + +:: + + <h2>Create a news item</h2> + + <?php echo validation_errors(); ?> + + <?php echo form_open('news/create') ?> + + <label for="title">Title</label> + <input type="input" name="title" /><br /> + + <label for="text">Text</label> + <textarea name="text"></textarea><br /> + + <input type="submit" name="submit" value="Create news item" /> + + </form> + +There are only two things here that probably look unfamiliar to you: the +form_open() function and the validation_errors() function. + +The first function is provided by the `form +helper <../helpers/form_helper.html>`_ and renders the form element and +adds extra functionality, like adding a hidden `CSFR prevention +field <../libraries/security.html>`_. The latter is used to report +errors related to form validation. + +Go back to your news controller. You're going to do two things here, +check whether the form was submitted and whether the submitted data +passed the validation rules. You'll use the `form +validation <../libraries/form_validation.html>`_ library to do this. + +:: + + public function create() + { + $this->load->helper('form'); + $this->load->library('form_validation'); + + $data['title'] = 'Create a news item'; + + $this->form_validation->set_rules('title', 'Title', 'required'); + $this->form_validation->set_rules('text', 'text', 'required'); + + if ($this->form_validation->run() === FALSE) + { + $this->load->view('templates/header', $data); + $this->load->view('news/create'); + $this->load->view('templates/footer'); + + } + else + { + $this->news_model->set_news(); + $this->load->view('news/success'); + } + } + +The code above adds a lot of functionality. The first few lines load the +form helper and the form validation library. After that, rules for the +form validation are set. The set\_rules() method takes three arguments; +the name of the input field, the name to be used in error messages, and +the rule. In this case the title and text fields are required. + +CodeIgniter has a powerful form validation library as demonstrated +above. You can read `more about this library +here <../libraries/form_validation.html>`_. + +Continuing down, you can see a condition that checks whether the form +validation ran successfully. If it did not, the form is displayed, if it +was submitted **and** passed all the rules, the model is called. After +this, a view is loaded to display a success message. Create a view at +application/view/news/success.php and write a success message. + +Model +----- + +The only thing that remains is writing a method that writes the data to +the database. You'll use the Active Record class to insert the +information and use the input library to get the posted data. Open up +the model created earlier and add the following: + +:: + + public function set_news() + { + $this->load->helper('url'); + + $slug = url_title($this->input->post('title'), 'dash', TRUE); + + $data = array( + 'title' => $this->input->post('title'), + 'slug' => $slug, + 'text' => $this->input->post('text') + ); + + return $this->db->insert('news', $data); + } + +This new method takes care of inserting the news item into the database. +The third line contains a new function, url\_title(). This function - +provided by the `URL helper <../helpers/url_helper.html>`_ - strips down +the string you pass it, replacing all spaces by dashes (-) and makes +sure everything is in lowercase characters. This leaves you with a nice +slug, perfect for creating URIs. + +Let's continue with preparing the record that is going to be inserted +later, inside the $data array. Each element corresponds with a column in +the database table created earlier. You might notice a new method here, +namely the post() method from the `input +library <../libraries/input.html>`_. This method makes sure the data is +sanitized, protecting you from nasty attacks from others. The input +library is loaded by default. At last, you insert our $data array into +our database. + +Routing +------- + +Before you can start adding news items into your CodeIgniter application +you have to add an extra rule to config/routes.php file. Make sure your +file contains the following. This makes sure CodeIgniter sees 'create' +as a method instead of a news item's slug. + +:: + + $route['news/create'] = 'news/create'; + $route['news/(:any)'] = 'news/view/$1'; + $route['news'] = 'news'; + $route['(:any)'] = 'pages/view/$1'; + $route['default_controller'] = 'pages/view'; + +Now point your browser to your local development environment where you +installed CodeIgniter and add index.php/news/create to the URL. +Congratulations, you just created your first CodeIgniter application! +Add some news and check out the different pages you made. diff --git a/user_guide_src/source/tutorial/index.rst b/user_guide_src/source/tutorial/index.rst new file mode 100644 index 000000000..eb6f11e34 --- /dev/null +++ b/user_guide_src/source/tutorial/index.rst @@ -0,0 +1,47 @@ +######## +Tutorial +######## + +This tutorial is intended to introduce you to the CodeIgniter framework +and the basic principles of MVC architecture. It will show you how a +basic CodeIgniter application is constructed in step-by-step fashion. + +In this tutorial, you will be creating a **basic news application**. You +will begin by writing the code that can load static pages. Next, you +will create a news section that reads news items from a database. +Finally, you'll add a form to create news items in the database. + +This tutorial will primarily focus on: + +- Model-View-Controller basics +- Routing basics +- Form validation +- Performing basic database queries using "Active Record" + +The entire tutorial is split up over several pages, each explaining a +small part of the functionality of the CodeIgniter framework. You'll go +through the following pages: + +- Introduction, this page, which gives you an overview of what to + expect. +- `Static pages <static_pages.html>`_, which will teach you the basics + of controllers, views and routing. +- `News section <news_section.html>`_, where you'll start using models + and will be doing some basic database operations. +- `Create news items <create_news_items.html>`_, which will introduce + more advanced database operations and form validation. +- `Conclusion <conclusion.html>`_, which will give you some pointers on + further reading and other resources. + +Enjoy your exploration of the CodeIgniter framework. + +.. toctree:: + :glob: + :hidden: + :titlesonly: + + index + static_pages + news_section + create_news_items + conclusion
\ No newline at end of file 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'; + $route['default_controller'] = 'pages/view'; + +Point your browser to your document root, followed by index.php/news and +watch your news page. diff --git a/user_guide_src/source/tutorial/static_pages.rst b/user_guide_src/source/tutorial/static_pages.rst new file mode 100644 index 000000000..0bbf51b1b --- /dev/null +++ b/user_guide_src/source/tutorial/static_pages.rst @@ -0,0 +1,170 @@ +############ +Static pages +############ + +**Note:** This tutorial assumes you've downloaded CodeIgniter and +`installed the framework <../installation/index.html>`_ in your +development environment. + +The first thing you're going to do is set up a **controller** to handle +static pages. A controller is simply a class that helps delegate work. +It is the glue of your web application. + +For example, when a call is made to: +``http://example.com/news/latest/10`` We might imagine that there is a +controller named "news". The method being called on news would be +"latest". The news method's job could be to grab 10 news items, and +render them on the page. Very often in MVC, you'll see URL patterns that +match: +``http://example.com/[controller-class]/[controller-method]/[arguments]`` +As URL schemes become more complex, this may change. But for now, this +is all we will need to know. + +Create a file at application/controllers/pages.php with the following +code. + +:: + + <?php + class Pages extends CI_Controller { + + public function view($page == 'home') + { + + } + + } + +You have created a class named "pages", with a view method that accepts +one argument named $page. 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 +(system/core/Controller.php). + +The **controller is what will become the center of every request** to +your web application. In very technical CodeIgniter discussions, it may +be referred to as the *super object*. Like any php class, you refer to +it within your controllers as $this. Referring to $this is how you will +load libraries, views, and generally command the framework. + +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. + +Create the header at application/views/templates/header.php and add the +following code. + +:: + + <html> + <head> + <title>CodeIgniter 2 Tutorial</title> + </head> + <body> + + <h1>CodeIgniter 2 Tutorial<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 $title variable, which we'll define later in the controller. +Now create a footer at application/views/templates/footer.php that +includes the following code: + +:: + + <em>© 2011</em> + </body> + <html> + +Adding logic to the controller +------------------------------ + +Earlier you set up a controller with a view() method. The method accepts +one parameter, which is the name of the page to be loaded. The static +page templates will be located in the application/views/pages/ +directory. + +In that directory, create two files named home.php and about.php. Within +those files, type some text − anything you'd like − and save them. If +you like to be particularly un-original, try "Hello World!". + +In order to load those pages, you'll have to check whether the requested +page actually exists: + +:: + + <?php + public function view($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); + + } + +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 +`documentation <../general/routing.html>`_. + +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! |