diff options
Diffstat (limited to 'user_guide/general/helpers.html')
| -rw-r--r-- | user_guide/general/helpers.html | 368 |
1 files changed, 184 insertions, 184 deletions
diff --git a/user_guide/general/helpers.html b/user_guide/general/helpers.html index 090456fc9..02f4511ba 100644 --- a/user_guide/general/helpers.html +++ b/user_guide/general/helpers.html @@ -1,185 +1,185 @@ -<!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 1.7</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>system/application/helpers </dfn>directory. CodeIgniter will look first in your <dfn>system/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="plugins.html">Plugins</a>
-</p>
-<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006-2008 · <a href="http://ellislab.com/">Ellislab, Inc.</a></p>
-</div>
-
-</body>
+<!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 1.7</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>system/application/helpers </dfn>directory. CodeIgniter will look first in your <dfn>system/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="plugins.html">Plugins</a> +</p> +<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006-2008 · <a href="http://ellislab.com/">Ellislab, Inc.</a></p> +</div> + +</body> </html>
\ No newline at end of file |