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www.giggi.me / code-igniter-v3-giggi / 78c3fa83531d4c1ca292f64e9383a9a4ff0f795b / . / user_guide / general / ancillary_classes.html
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Derek Allard404e35d2007-08-07 01:00:45 +0000[diff] [blame]5<title>CodeIgniter User Guide : Creating Ancillary Classes</title>
adminb0dd10f2006-08-25 17:25:49 +0000[diff] [blame]6
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45Creating Ancillary Classes
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58<h1>Creating Ancillary Classes</h1>
59
admine334c472006-10-21 19:44:22 +0000[diff] [blame]60<p>In some cases you may want to develop classes that exist apart from your controllers but have the ability to
Derek Allardd2df9bc2007-04-15 17:41:17 +0000[diff] [blame]61utilize all of CodeIgniter's resources. This is easily possible as you'll see.</p>
adminb0dd10f2006-08-25 17:25:49 +0000[diff] [blame]62
63<h2>get_instance()</h2>
64
65
Derek Allardd2df9bc2007-04-15 17:41:17 +0000[diff] [blame]66<p><strong>Any class that you instantiate within your controller functions can access CodeIgniter's native resources</strong> simply by using the <kbd>get_instance()</kbd> function.
67This function returns the main CodeIgniter object.</p>
adminb0dd10f2006-08-25 17:25:49 +0000[diff] [blame]68
Derek Allardd2df9bc2007-04-15 17:41:17 +0000[diff] [blame]69<p>Normally, to call any of the available CodeIgniter functions requires you to use the <kbd>$this</kbd> construct:</p>
adminb0dd10f2006-08-25 17:25:49 +0000[diff] [blame]70
71<code>
72<strong>$this</strong>->load->helper('url');<br />
73<strong>$this</strong>->load->library('session');<br />
74<strong>$this</strong>->config->item('base_url');<br />
75etc.
76</code>
77
admine334c472006-10-21 19:44:22 +0000[diff] [blame]78<p><kbd>$this</kbd>, however, only works within your controllers, your models, or your views.
Derek Allardd2df9bc2007-04-15 17:41:17 +0000[diff] [blame]79If you would like to use CodeIgniter's classes from within your own custom classes you can do so as follows:</p>
adminb0dd10f2006-08-25 17:25:49 +0000[diff] [blame]80
81
Derek Allardd2df9bc2007-04-15 17:41:17 +0000[diff] [blame]82<p>First, assign the CodeIgniter object to a variable:</p>
adminb0dd10f2006-08-25 17:25:49 +0000[diff] [blame]83
admin88a8ad12006-10-07 03:16:32 +0000[diff] [blame]84<code>$CI =& get_instance();</code>
adminb0dd10f2006-08-25 17:25:49 +0000[diff] [blame]85
86<p>Once you've assigned the object to a variable, you'll use that variable <em>instead</em> of <kbd>$this</kbd>:</p>
87
88<code>
admin88a8ad12006-10-07 03:16:32 +0000[diff] [blame]89$CI =& get_instance();<br /><br />
90$CI->load->helper('url');<br />
91$CI->load->library('session');<br />
92$CI->config->item('base_url');<br />
adminb0dd10f2006-08-25 17:25:49 +0000[diff] [blame]93etc.
94</code>
95
96<p class="important"><strong>Note:</strong> You'll notice that the above get_instance() function is being passed by reference:
97<br /><br />
admin88a8ad12006-10-07 03:16:32 +0000[diff] [blame]98<var>$CI =& get_instance();</var>
adminb0dd10f2006-08-25 17:25:49 +0000[diff] [blame]99<br /><br />
Derek Allardd2df9bc2007-04-15 17:41:17 +0000[diff] [blame]100This is very important. Assigning by reference allows you to use the original CodeIgniter object rather than creating a copy of it.</p>
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Derek Allardc6441282007-07-04 23:54:32 +0000[diff] [blame]112</p>
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