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| author | Joël Cox <joel@joelcox.nl> | 2011-10-09 18:39:39 +0200 |
|---|---|---|
| committer | Joël Cox <joel@joelcox.nl> | 2011-10-09 18:39:39 +0200 |
| commit | f4fb1db458fab52d0493ead52c9ea7e01206eaa7 (patch) | |
| tree | c549600f342f4d3f0df75a2f2f7c265be0f1cc72 /user_guide/general/creating_libraries.html | |
| parent | c4dd200c1155a118afa32cd91d9bd67bc243f83a (diff) | |
Moved tutorial to new user guide directory.
Diffstat (limited to 'user_guide/general/creating_libraries.html')
| -rw-r--r-- | user_guide/general/creating_libraries.html | 293 |
1 files changed, 0 insertions, 293 deletions
diff --git a/user_guide/general/creating_libraries.html b/user_guide/general/creating_libraries.html deleted file mode 100644 index aeec871b2..000000000 --- a/user_guide/general/creating_libraries.html +++ /dev/null @@ -1,293 +0,0 @@ -<!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 2.0.3</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 /> - public function some_function()<br /> - {<br /> - }<br /> -}<br /><br /> -/* End of file Someclass.php */</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>$params</kbd>);</code> - -<p>If you use this feature you must set up your class constructor to expect data:</p> - -<code><?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');<br /> -<br /> -class Someclass {<br /> -<br /> - public function __construct($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 /> - public 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>
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