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| author | admin <devnull@localhost> | 2006-08-25 19:25:49 +0200 |
|---|---|---|
| committer | admin <devnull@localhost> | 2006-08-25 19:25:49 +0200 |
| commit | b0dd10f8171945e0c1f3527dd1e9d18b043e01a7 (patch) | |
| tree | c3583ba09e72217683c4304f4690df6ce39ba731 /user_guide/general/creating_libraries.html | |
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diff --git a/user_guide/general/creating_libraries.html b/user_guide/general/creating_libraries.html new file mode 100644 index 000000000..fa3416767 --- /dev/null +++ b/user_guide/general/creating_libraries.html @@ -0,0 +1,222 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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+<td><h1>Code Igniter User Guide Version 1.4.0</h1></td>
+<td id="breadcrumb_right"><a href="../toc.html">Full Table of Contents</a></td>
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+<a href="http://www.codeigniter.com/">Code Igniter Home</a> ›
+<a href="../index.html">User Guide Home</a> ›
+Creating Libraries
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+<div id="content">
+
+<h1>Creating Libraries</h1>
+
+<p>When we use the term "Libraries" we are normally referring to the classes that are located in the <kbd>libraries</kbd>
+directory and described in the Class Reference of this user guide. In this case, however, we will instead describe how you can create your own libraries within
+your <dfn>application</dfn> directory in order to maintain separation between your local resources and the global framework resources.</p>
+
+<h2>Storage</h2>
+
+<p>In order for your libraries to be stored in your <kbd>application</kbd> folder you will need to create two directories in which to store them:</p>
+
+<ul>
+<li>application/<dfn>init</dfn></li>
+<li>application/<dfn>libraries</dfn></li>
+</ul>
+
+
+<h2>Anatomy of a Library</h2>
+
+<p>A class library consists of two components:</p>
+
+<ol>
+<li>An <kbd>init</kbd> file.</li>
+<li>A <kbd>class</kbd> file.</li>
+</ol>
+
+<h2>The Init File</h2>
+
+<p>An <kbd>init</kbd> file a small initialization file corresponding to each of your classes. The purpose of this file is to
+instantiate a particular class. Each init file must be named identically to your class file name, adding the "init_" prefix. For example, if your
+class is named <dfn>myclass.php</dfn> your init file will be named:</p>
+
+<code>init_myclass.php</code>
+
+<p>Within your init file you will place your initialization code. Here's an example of such code, using an imaginary class named <kbd>Myclass</kbd>:</p>
+
+
+<code><?php if (!defined('BASEPATH')) exit('No direct script access allowed');<br />
+<br />
+if ( ! class_exists('<kbd>Myclass</kbd>'))<br />
+{<br />
+ require_once(APPPATH.'libraries/<kbd>Myclass</kbd>'.EXT);<br />
+}<br />
+<br />
+$obj =& get_instance();<br />
+$obj-><kbd>myclass</kbd> = new <kbd>Myclass();</kbd><br />
+$obj->ci_is_loaded[] = '<kbd>myclass</kbd>';<br />
+<br />
+?></code>
+
+<h2>The Class File</h2>
+
+<p>Your class file itself will be placed inside your <dfn>libraries</dfn> directory:</p>
+
+<code>application/libraries/<dfn>myclass.php</dfn></code>
+
+<p>The class will have this basic prototype:</p>
+
+<code><?php if (!defined('BASEPATH')) exit('No direct script access allowed');<br />
+<br />
+class Myclass {<br />
+<br />
+}<br />
+?></code>
+
+
+<h2>Naming Conventions</h2>
+
+<ul>
+<li>All file names must be in lowercase: myclass.php and init_myclass.php</li>
+<li>Class names must be capitalize: class Myclass</li>
+</ul>
+
+
+<h2>Using Your Class</h2>
+
+<p>From within any of your <a href="controllers.html">Controller</a> classes you can initialize your class using the standard:</p>
+
+<code>$this->load->library('<kbd>myclass</kbd>');</code>
+
+<p>Once loaded you can access your class using:</p>
+
+<code>$this-><kbd>myclass</kbd>->function();</code>
+
+<p>Note: In your init file you can define the object variable name.</p>
+
+
+<h2>Passing Parameters Your Class</h2>
+
+<p>In the library loading function you can pass data via the second parameter and it will be available to your initialization file:</p>
+
+<code>
+$params = array('type' => 'large', 'color' => 'red');<br />
+<br />
+$this->load->library('myclass', <kbd>$params</kbd>);</code>
+
+<p>Parameters will be accessible using a variable called <kbd>$params</kbd>. By default this variable is set to FALSE.</p>
+
+
+<h2>Utilizing Code Igniter Resources within Your Library</h2>
+
+
+<p>To access Code Igniter's native resources within your library use the <kbd>get_instance()</kbd> function.
+This function returns the Code Igniter super object.</p>
+
+<p>Normally, to call any of the available Code Igniter functions requires you to use the <kbd>$this</kbd> construct:</p>
+
+<code>
+<strong>$this</strong>->load->helper('url');<br />
+<strong>$this</strong>->load->library('session');<br />
+<strong>$this</strong>->config->item('base_url');<br />
+etc.
+</code>
+
+<p><kbd>$this</kbd>, however, only works directly within your controllers, your models, or your views.
+If you would like to use Code Igniter's classes from within your own custom classes you can do so as follows:</p>
+
+
+<p>First, assign the Code Igniter object to a variable:</p>
+
+<code>$obj =& get_instance();</code>
+
+<p>Once you've assigned the object to a variable, you'll use that variable <em>instead</em> of <kbd>$this</kbd>:</p>
+
+<code>
+$obj =& get_instance();<br /><br />
+$obj->load->helper('url');<br />
+$obj->load->library('session');<br />
+$obj->config->item('base_url');<br />
+etc.
+</code>
+
+<p class="important"><strong>Note:</strong> You'll notice that the above get_instance() function is being passed by reference:
+<br /><br />
+<var>$obj =& get_instance();</var>
+<br /><br />
+<kbd>This is very important.</kbd> Assigning by reference allows you to use the original Code Igniter object rather than creating a copy of it.</p>
+
+
+
+
+
+
+
+</div>
+<!-- END CONTENT -->
+
+
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+<p>
+Previous Topic: <a href="libraries.html">Using Libraries</a>
+ ·
+<a href="#top">Top of Page</a> ·
+<a href="../index.html">User Guide Home</a> ·
+Next Topic: <a href="ancillary_classes.html">Creating Ancillary Classes</a>
+<p>
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