293 行
11 KiB
HTML
293 行
11 KiB
HTML
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
||
|
|
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
|
||
|
|
<head>
|
||
|
|
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
||
|
|
<title>Creating Libraries : CodeIgniter User Guide</title>
|
||
|
|
|
||
|
|
<style type='text/css' media='all'>@import url('../userguide.css');</style>
|
||
|
|
<link rel='stylesheet' type='text/css' media='all' href='../userguide.css' />
|
||
|
|
|
||
|
|
<script type="text/javascript" src="../nav/nav.js"></script>
|
||
|
|
<script type="text/javascript" src="../nav/prototype.lite.js"></script>
|
||
|
|
<script type="text/javascript" src="../nav/moo.fx.js"></script>
|
||
|
|
<script type="text/javascript" src="../nav/user_guide_menu.js"></script>
|
||
|
|
|
||
|
|
<meta http-equiv='expires' content='-1' />
|
||
|
|
<meta http-equiv= 'pragma' content='no-cache' />
|
||
|
|
<meta name='robots' content='all' />
|
||
|
|
<meta name='author' content='ExpressionEngine Dev Team' />
|
||
|
|
<meta name='description' content='CodeIgniter User Guide' />
|
||
|
|
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
|
||
|
|
<!-- START NAVIGATION -->
|
||
|
|
<div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div>
|
||
|
|
<div id="nav2"><a name="top"></a><a href="javascript:void(0);" onclick="myHeight.toggle();"><img src="../images/nav_toggle_darker.jpg" width="154" height="43" border="0" title="Toggle Table of Contents" alt="Toggle Table of Contents" /></a></div>
|
||
|
|
<div id="masthead">
|
||
|
|
<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
|
||
|
|
<tr>
|
||
|
|
<td><h1>CodeIgniter User Guide Version 2.0.1</h1></td>
|
||
|
|
<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
</div>
|
||
|
|
<!-- END NAVIGATION -->
|
||
|
|
|
||
|
|
|
||
|
|
<!-- START BREADCRUMB -->
|
||
|
|
<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
|
||
|
|
<tr>
|
||
|
|
<td id="breadcrumb">
|
||
|
|
<a href="http://codeigniter.com/">CodeIgniter Home</a> ›
|
||
|
|
<a href="../index.html">User Guide Home</a> ›
|
||
|
|
Creating Libraries
|
||
|
|
</td>
|
||
|
|
<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" /> <input type="submit" class="submit" name="sa" value="Go" /></form></td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
<!-- END BREADCRUMB -->
|
||
|
|
|
||
|
|
<br clear="all" />
|
||
|
|
|
||
|
|
|
||
|
|
<!-- START CONTENT -->
|
||
|
|
<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/libraries</dfn> directory in order to maintain separation between your local resources
|
||
|
|
and the global framework resources.</p>
|
||
|
|
|
||
|
|
<p>As an added bonus, CodeIgniter permits your libraries to <kbd>extend</kbd> native classes if you simply need to add some functionality
|
||
|
|
to an existing library. Or you can even replace native libraries just by placing identically named versions in your <dfn>application/libraries</dfn> folder.</p>
|
||
|
|
|
||
|
|
<p>In summary:</p>
|
||
|
|
|
||
|
|
<ul>
|
||
|
|
<li>You can create entirely new libraries.</li>
|
||
|
|
<li>You can extend native libraries.</li>
|
||
|
|
<li>You can replace native libraries.</li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
<p>The page below explains these three concepts in detail.</p>
|
||
|
|
|
||
|
|
<p class="important"><strong>Note:</strong> The Database classes can not be extended or replaced with your own classes. All other classes are able to be replaced/extended.</p>
|
||
|
|
|
||
|
|
|
||
|
|
<h2>Storage</h2>
|
||
|
|
|
||
|
|
<p>Your library classes should be placed within your <dfn>application/libraries</dfn> folder, as this is where CodeIgniter will look for them when
|
||
|
|
they are initialized.</p>
|
||
|
|
|
||
|
|
|
||
|
|
<h2>Naming Conventions</h2>
|
||
|
|
|
||
|
|
<ul>
|
||
|
|
<li>File names must be capitalized. For example: <dfn>Myclass.php</dfn></li>
|
||
|
|
<li>Class declarations must be capitalized. For example: <kbd>class Myclass</kbd></li>
|
||
|
|
<li>Class names and file names must match.</li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
|
||
|
|
<h2>The Class File</h2>
|
||
|
|
|
||
|
|
<p>Classes should have this basic prototype (Note: We are using the name <kbd>Someclass</kbd> purely as an example):</p>
|
||
|
|
|
||
|
|
<code><?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
|
||
|
|
<br /><br />
|
||
|
|
class Someclass {<br />
|
||
|
|
<br />
|
||
|
|
function some_function()<br />
|
||
|
|
{<br />
|
||
|
|
}<br />
|
||
|
|
}<br /><br />
|
||
|
|
?></code>
|
||
|
|
|
||
|
|
|
||
|
|
<h2>Using Your Class</h2>
|
||
|
|
|
||
|
|
<p>From within any of your <a href="controllers.html">Controller</a> functions you can initialize your class using the standard:</p>
|
||
|
|
|
||
|
|
<code>$this->load->library('<kbd>someclass</kbd>');</code>
|
||
|
|
|
||
|
|
<p>Where <em>someclass</em> is the file name, without the ".php" file extension. You can submit the file name capitalized or lower case.
|
||
|
|
CodeIgniter doesn't care.</p>
|
||
|
|
|
||
|
|
<p>Once loaded you can access your class using the <kbd>lower case</kbd> version:</p>
|
||
|
|
|
||
|
|
<code>$this-><kbd>someclass</kbd>->some_function(); // Object instances will always be lower case
|
||
|
|
</code>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<h2>Passing Parameters When Initializing Your Class</h2>
|
||
|
|
|
||
|
|
<p>In the library loading function you can dynamically pass data as an array via the second parameter and it will be passed to your class
|
||
|
|
constructor:</p>
|
||
|
|
|
||
|
|
<code>
|
||
|
|
$params = array('type' => 'large', 'color' => 'red');<br />
|
||
|
|
<br />
|
||
|
|
$this->load->library('Someclass', <kbd>$params</kbd>);</code>
|
||
|
|
|
||
|
|
<p>If you use this feature you must set up your class constructor to expect data:</p>
|
||
|
|
|
||
|
|
<code><?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');<br />
|
||
|
|
<br />
|
||
|
|
class Someclass {<br />
|
||
|
|
<br />
|
||
|
|
function __construct($params)<br />
|
||
|
|
{<br />
|
||
|
|
// Do something with $params<br />
|
||
|
|
}<br />
|
||
|
|
}<br /><br />
|
||
|
|
?></code>
|
||
|
|
|
||
|
|
<p class="important">You can also pass parameters stored in a config file. Simply create a config file named identically to the class <kbd>file name</kbd>
|
||
|
|
and store it in your <dfn>application/config/</dfn> folder. Note that if you dynamically pass parameters as described above,
|
||
|
|
the config file option will not be available.</p>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<h2>Utilizing CodeIgniter Resources within Your Library</h2>
|
||
|
|
|
||
|
|
|
||
|
|
<p>To access CodeIgniter's native resources within your library use the <kbd>get_instance()</kbd> function.
|
||
|
|
This function returns the CodeIgniter super object.</p>
|
||
|
|
|
||
|
|
<p>Normally from within your controller functions you will call any of the available CodeIgniter functions using the <kbd>$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 CodeIgniter's classes from within your own custom classes you can do so as follows:</p>
|
||
|
|
|
||
|
|
|
||
|
|
<p>First, assign the CodeIgniter object to a variable:</p>
|
||
|
|
|
||
|
|
<code>$CI =& get_instance();</code>
|
||
|
|
|
||
|
|
<p>Once you've assigned the object to a variable, you'll use that variable <em>instead</em> of <kbd>$this</kbd>:</p>
|
||
|
|
|
||
|
|
<code>
|
||
|
|
$CI =& get_instance();<br />
|
||
|
|
<br />
|
||
|
|
$CI->load->helper('url');<br />
|
||
|
|
$CI->load->library('session');<br />
|
||
|
|
$CI->config->item('base_url');<br />
|
||
|
|
etc.
|
||
|
|
</code>
|
||
|
|
|
||
|
|
<p class="important"><strong>Note:</strong> You'll notice that the above get_instance() function is being passed by reference:
|
||
|
|
<br /><br />
|
||
|
|
<var>$CI =& get_instance();</var>
|
||
|
|
<br />
|
||
|
|
<br />
|
||
|
|
<kbd>This is very important.</kbd> Assigning by reference allows you to use the original CodeIgniter object rather than creating a copy of it.</p>
|
||
|
|
|
||
|
|
|
||
|
|
<h2>Replacing Native Libraries with Your Versions</h2>
|
||
|
|
|
||
|
|
<p>Simply by naming your class files identically to a native library will cause CodeIgniter to use it instead of the native one. To use this
|
||
|
|
feature you must name the file and the class declaration exactly the same as the native library. For example, to replace the native <kbd>Email</kbd> library
|
||
|
|
you'll create a file named <dfn>application/libraries/Email.php</dfn>, and declare your class with:</p>
|
||
|
|
|
||
|
|
<code>
|
||
|
|
class CI_Email {<br /><br />
|
||
|
|
|
||
|
|
}</code>
|
||
|
|
|
||
|
|
<p>Note that most native classes are prefixed with <kbd>CI_</kbd>.</p>
|
||
|
|
|
||
|
|
<p>To load your library you'll see the standard loading function:</p>
|
||
|
|
|
||
|
|
<code>$this->load->library('<kbd>email</kbd>');</code>
|
||
|
|
|
||
|
|
<p class="important"><strong>Note:</strong> At this time the Database classes can not be replaced with your own versions.</p>
|
||
|
|
|
||
|
|
|
||
|
|
<h2>Extending Native Libraries</h2>
|
||
|
|
|
||
|
|
<p>If all you need to do is add some functionality to an existing library - perhaps add a function or two - then
|
||
|
|
it's overkill to replace the entire library with your version. In this case it's better to simply extend the class.
|
||
|
|
Extending a class is nearly identical to replacing a class with a couple exceptions:</p>
|
||
|
|
|
||
|
|
<ul>
|
||
|
|
<li>The class declaration must extend the parent class.</li>
|
||
|
|
<li>Your new class name and filename must be prefixed with <kbd>MY_</kbd> (this item is configurable. See below.).</li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
<p>For example, to extend the native <kbd>Email</kbd> class you'll create a file named <dfn>application/libraries/</dfn><kbd>MY_Email.php</kbd>, and declare your class with:</p>
|
||
|
|
|
||
|
|
<code>
|
||
|
|
class MY_Email extends CI_Email {<br /><br />
|
||
|
|
|
||
|
|
}</code>
|
||
|
|
|
||
|
|
<p>Note: If you need to use a constructor in your class make sure you extend the parent constructor:</p>
|
||
|
|
|
||
|
|
|
||
|
|
<code>
|
||
|
|
class MY_Email extends CI_Email {<br />
|
||
|
|
<br />
|
||
|
|
function __construct()<br />
|
||
|
|
{<br />
|
||
|
|
parent::__construct();<br />
|
||
|
|
}<br />
|
||
|
|
}</code>
|
||
|
|
|
||
|
|
|
||
|
|
<h3>Loading Your Sub-class</h3>
|
||
|
|
|
||
|
|
<p>To load your sub-class you'll use the standard syntax normally used. DO NOT include your prefix. For example,
|
||
|
|
to load the example above, which extends the Email class, you will use:</p>
|
||
|
|
|
||
|
|
<code>$this->load->library('<kbd>email</kbd>');</code>
|
||
|
|
|
||
|
|
<p>Once loaded you will use the class variable as you normally would for the class you are extending. In the case of
|
||
|
|
the email class all calls will use:</p>
|
||
|
|
|
||
|
|
|
||
|
|
<code>$this-><kbd>email</kbd>->some_function();</code>
|
||
|
|
|
||
|
|
|
||
|
|
<h3>Setting Your Own Prefix</h3>
|
||
|
|
|
||
|
|
<p>To set your own sub-class prefix, open your <dfn>application/config/config.php</dfn> file and look for this item:</p>
|
||
|
|
|
||
|
|
<code>$config['subclass_prefix'] = 'MY_';</code>
|
||
|
|
|
||
|
|
<p>Please note that all native CodeIgniter libraries are prefixed with <kbd>CI_</kbd> so DO NOT use that as your prefix.</p>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</div>
|
||
|
|
<!-- END CONTENT -->
|
||
|
|
|
||
|
|
|
||
|
|
<div id="footer">
|
||
|
|
<p>
|
||
|
|
Previous Topic: <a href="libraries.html">Using CodeIgniter Libraries</a>
|
||
|
|
·
|
||
|
|
<a href="#top">Top of Page</a> ·
|
||
|
|
<a href="../index.html">User Guide Home</a> ·
|
||
|
|
Next Topic: <a href="drivers.html">Using CodeIgniter Drivers</a>
|
||
|
|
</p>
|
||
|
|
<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006 - 2011 · <a href="http://ellislab.com/">EllisLab, Inc.</a></p>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|