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Joël Coxb430ecd2011-08-23 14:54:42 +0200[diff] [blame^]31<td><h1>CodeIgniter User Guide Version 2.0.3</h1></td>
Joël Coxf27bcf32011-08-22 22:29:06 +0200[diff] [blame]32<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
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43<a href="http://codeigniter.com/">CodeIgniter Home</a> &nbsp;&#8250;&nbsp;
44<a href="../index.html">User Guide Home</a> &nbsp;&#8250;&nbsp;
45<a href="introduction.html">Tutorial</a> &nbsp;&#8250;&nbsp;
46Static pages
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59
60<h1>Tutorial &minus; Static pages</h1>
61
62<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>
63
64<p>The first thing you're going to do is set up a <strong>controller</strong> to handle static pages.
65A controller is simply a class that helps delegate work. It is the glue of your
66web application.</p>
67
68<p>For example, when a call is made to: <code>http://example.com/news/latest/10</code> We might imagine
69that there is a controller named &quot;news&quot;. The method being called on news
70would be &quot;latest&quot;. The news method's job could be to grab 10
71news items, and render them on the page. Very often in MVC, you'll see URL
72patterns that match: <code>http://example.com/[controller-class]/[controller-method]/[arguments]</code>
73As URL schemes become more complex, this may change. But for now, this is all we will need to know.</p>
74
75<p>Create a file at <dfn>application/controllers/pages.php</dfn> with the following code.</p>
76
77<textarea class="textarea" style="width:100%" cols="50" rows="10">
78&lt;?php
79
80class Pages extends CI_Controller {
81
82 function view($page = 'home')
83 {
84
85 }
86}
87</textarea>
88
89<p>You have created a class named &quot;pages&quot;, with a view method that accepts one argument named <var>$page</var>.
90The pages class is extending the CI_Controller class.
91This means that the new pages class can access the methods and variables defined in the CI_Controller class
92(<dfn>system/core/Controller.php</dfn>).</p>
93
94<p>The <strong>controller is what will become the center of every request</strong> to your web application.
95In very technical CodeIgniter discussions, it may be referred to as the <em>super object</em>.
96Like any php class, you refer to it within your controllers as <var>$this</var>.
97Referring to <var>$this</var> is how you will load libraries, views, and generally
98command the framework.</p>
99
100<p>Now you've created your first method, it's time to make some basic page templates.
101We will be creating two &quot;views&quot; (page templates) that act as our page footer and header.</p>
102
103<p>Create the header at <dfn>application/views/templates/header.php</dfn> and add the following code.</p>
104
105<textarea class="textarea" style="width:100%" cols="50" rows="8">
106<html>
107<head>
108 <title><?php echo $title ?> - CodeIgniter 2 Tutorial</title>
109</head>
110<body>
111 <h1>CodeIgniter 2 Tutorial</h1>
112
113</textarea>
114
115<p>The header contains the basic HTML code that you'll want to display before loading the main view, together with a heading.
116It will also output the <var>$title</var> variable, which we'll define later in the controller.
117Now create a footer at <dfn>application/views/templates/footer.php</dfn> that includes the following code:</p>
118
119<textarea class="textarea" style="width:100%" cols="50" rows="4">
120<strong>&#38;copy; 2011</strong>
121</body>
122</html>
123</textarea>
124
125<h2>Adding logic to the controller</h2>
126
127<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.
128The static page templates will be located in the <dfn>application/views/pages/</dfn> directory.</p>
129
130<p>In that directory, create two files named <dfn>home.php</dfn> and <dfn>about.php</dfn>.
131Within those files, type some text &minus; anything you'd like &minus; and save them.
132If you like to be particularly un-original, try &quot;Hello World!&quot;.</p>
133
134<p>In order to load those pages, you'll have to check whether the requested page actually exists:</p>
135
136<pre>
137function view($page = 'home')
138{
139
140 if ( ! file_exists('application/views/pages/' . $page . EXT))
141 {
142 // Whoops, we don't have a page for that!
143 show_404();
144 }
145
146 $data['title'] = ucfirst($page); // Capitalize the first letter
147
148 $this->load->view('templates/header', $data);
149 $this->load->view('pages/' . $page, $data);
150 $this->load->view('templates/footer', $data);
151
152}
153</pre>
154
155<p>Now, when the page does exist, it is loaded, including the header and footer, and displayed to the user. If the page doesn't exist, a "404 Page not found" error is shown.</p>
156
157<p>The first line in this method checks whether the page actually exists. PHP's native <var>file_exists()</var> function is used to check whether the file is where it's expected to be. <var>show_404()</var> is a built-in CodeIgniter function that renders the default error page.</p>
158
159<p>In the header template, the <var>$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>$data</var> array.</p>
160
161<p>The last thing that has to be done is loading the views in the order they should be displayed.
162The second parameter in the <var>view()</var> method is used to pass values to the view. Each value in the <var>$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 $title in the view.<p>
163
164<h2>Routing</h2>
165
166<p>The controller is now functioning! Point your browser to <dfn>[your-site-url]index.php/pages/view</dfn> to see your page. When you visit <dfn>index.php/pages/view/about</dfn> you'll see the about page, again including the header and footer.</p>
167
168<p>Using custom routing rules, you have the power to map any URI to any controller and method, and break free from the normal convention:
169<code>http://example.com/[controller-class]/[controller-method]/[arguments]</code></p>
170
171<p>Let's do that. Open the routing file located at <dfn>application/config/routes.php</dfn> and add the following two lines. Remove all other code that sets any element in the <var>$route</var> array.</p>
172
173<pre>
174$route['default_controller'] = 'pages';
175$route['(:any)'] = 'pages/view/$1';
176</pre>
177
178<p>CodeIgniter reads its routing rules from top to bottom and routes the request to the first matching rule. Each rule is a regular expression
179(left-side) mapped to a controller and method name separated by slashes (right-side).
180When a request comes in, CodeIgniter looks for the first match, and calls the appropriate controller and method, possibly with arguments.</p>
181
182<p>More information about routing can be found in the URI Routing <a href="../general/routing.html">documentation</a>.</p>
183
184<p>Here, the second rule in the <var>$routes</var> array matches <strong>any</strong> request using the wildcard string <dfn>(:any)</dfn>.
185and passes the parameter to the view() method of the pages class.</p>
186
187<p>Now visit <dfn>index.php/about</dfn>. Did it get routed correctly to the <var>view()</var> method
188in the pages controller? Awesome!</p>
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