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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/helpers.html | |
| parent | c4dd200c1155a118afa32cd91d9bd67bc243f83a (diff) | |
Moved tutorial to new user guide directory.
Diffstat (limited to 'user_guide/general/helpers.html')
| -rw-r--r-- | user_guide/general/helpers.html | 185 |
1 files changed, 0 insertions, 185 deletions
diff --git a/user_guide/general/helpers.html b/user_guide/general/helpers.html deleted file mode 100644 index 3747eb7b9..000000000 --- a/user_guide/general/helpers.html +++ /dev/null @@ -1,185 +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>Helper Functions : 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> › -Helper Functions -</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>Helper Functions</h1> - -<p>Helpers, as the name suggests, help you with tasks. Each helper file is simply a collection of functions in a particular -category. There are <dfn>URL Helpers</dfn>, that assist in creating links, there are <dfn>Form Helpers</dfn> -that help you create form elements, <dfn>Text Helpers</dfn> perform various text formatting routines, -<dfn>Cookie Helpers</dfn> set and read cookies, <dfn>File Helpers</dfn> help you deal with files, etc. -</p> - -<p>Unlike most other systems in CodeIgniter, Helpers are not written in an Object Oriented format. They are simple, procedural functions. -Each helper function performs one specific task, with no dependence on other functions.</p> - -<p>CodeIgniter does not load Helper Files by default, so the first step in using -a Helper is to load it. Once loaded, it becomes globally available in your <a href="../general/controllers.html">controller</a> and <a href="../general/views.html">views</a>.</p> - -<p>Helpers are typically stored in your <dfn>system/helpers</dfn>, or <dfn>application/helpers </dfn>directory. CodeIgniter will look first in your <dfn>application/helpers</dfn> -directory. If the directory does not exist or the specified helper is not located there CI will instead look in your global -<dfn>system/helpers</dfn> folder.</p> - - -<h2>Loading a Helper</h2> - -<p>Loading a helper file is quite simple using the following function:</p> - -<code>$this->load->helper('<var>name</var>');</code> - -<p>Where <var>name</var> is the file name of the helper, without the .php file extension or the "helper" part.</p> - -<p>For example, to load the <dfn>URL Helper</dfn> file, which is named <var>url_helper.php</var>, you would do this:</p> - -<code>$this->load->helper('<var>url</var>');</code> - -<p>A helper can be loaded anywhere within your controller functions (or even within your View files, although that's not a good practice), -as long as you load it before you use it. You can load your helpers in your controller constructor so that they become available -automatically in any function, or you can load a helper in a specific function that needs it.</p> - -<p class="important">Note: The Helper loading function above does not return a value, so don't try to assign it to a variable. Just use it as shown.</p> - - -<h2>Loading Multiple Helpers</h2> - -<p>If you need to load more than one helper you can specify them in an array, like this:</p> - -<code>$this->load->helper( <samp>array(</samp>'<var>helper1</var>', '<var>helper2</var>', '<var>helper3</var>'<samp>)</samp> );</code> - -<h2>Auto-loading Helpers</h2> - -<p>If you find that you need a particular helper globally throughout your application, you can tell CodeIgniter to auto-load it during system initialization. -This is done by opening the <var>application/config/autoload.php</var> file and adding the helper to the autoload array.</p> - - -<h2>Using a Helper</h2> - -<p>Once you've loaded the Helper File containing the function you intend to use, you'll call it the way you would a standard PHP function.</p> - -<p>For example, to create a link using the <dfn>anchor()</dfn> function in one of your view files you would do this:</p> - -<code><?php echo anchor('blog/comments', 'Click Here');?></code> - -<p>Where "Click Here" is the name of the link, and "blog/comments" is the URI to the controller/function you wish to link to.</p> - -<h2>"Extending" Helpers</h2> - -<p>To "extend" Helpers, create a file in your <dfn>application/helpers/</dfn> folder with an identical name to the existing Helper, but prefixed with <kbd>MY_</kbd> (this item is configurable. See below.).</p> - -<p>If all you need to do is add some functionality to an existing helper - perhaps add a function or two, or change how a particular - helper function operates - then it's overkill to replace the entire helper with your version. In this case it's better to simply - "extend" the Helper. The term "extend" is used loosely since Helper functions are procedural and discrete and cannot be extended - in the traditional programmatic sense. Under the hood, this gives you the ability to add to the functions a Helper provides, - or to modify how the native Helper functions operate.</p> - -<p>For example, to extend the native <kbd>Array Helper</kbd> you'll create a file named <dfn>application/helpers/</dfn><kbd>MY_array_helper.php</kbd>, and add or override functions:</p> - -<code> -// any_in_array() is not in the Array Helper, so it defines a new function<br /> -function any_in_array($needle, $haystack)<br /> -{<br /> - $needle = (is_array($needle)) ? $needle : array($needle);<br /> - <br /> - foreach ($needle as $item)<br /> - {<br /> - if (in_array($item, $haystack))<br /> - {<br /> - return TRUE;<br /> - }<br /> - }<br /> - <br /> - return FALSE;<br /> -}<br /> -<br /> -// random_element() is included in Array Helper, so it overrides the native function<br /> -function random_element($array)<br /> -{<br /> - shuffle($array);<br /> - return array_pop($array);<br /> -}<br /> -</code> - -<h3>Setting Your Own Prefix</h3> - -<p>The filename prefix for "extending" Helpers is the same used to extend libraries and Core classes. To set your own 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> - - -<h2>Now What?</h2> - -<p>In the Table of Contents you'll find a list of all the available Helper Files. Browse each one to see what they do.</p> - - -</div> -<!-- END CONTENT --> - - -<div id="footer"> -<p> -Previous Topic: <a href="models.html">Models</a> - · -<a href="#top">Top of Page</a> · -<a href="../index.html">User Guide Home</a> · -Next Topic: <a href="libraries.html">Using Libraries</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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