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Derek Jones8917af72010-03-05 12:41:45 -0600[diff] [blame]31<td><h1>CodeIgniter User Guide Version 2.0.0</h1></td>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]32<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
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45Loader Class
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58
59<h1>Loader Class</h1>
60
61<p>Loader, as the name suggests, is used to load elements. These elements can be libraries (classes) <a href="../general/views.html">View files</a>,
Derek Jonesc6da5032010-03-09 20:44:27 -0600[diff] [blame]62<a href="../general/helpers.html">Helpers</a>, <a href="../general/models.html">Models</a>, or your own files.</p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]63
64<p class="important"><strong>Note:</strong> This class is initialized automatically by the system so there is no need to do it manually.</p>
65
66<p>The following functions are available in this class:</p>
67
68
69<h2>$this->load->library('<var>class_name</var>', <samp>$config</samp>, <kbd>'object name'</kbd>)</h2>
70
71
72<p>This function is used to load core classes. Where <var>class_name</var> is the name of the class you want to load.
73Note: We use the terms "class" and "library" interchangeably.</p>
74
75<p>For example, if you would like to send email with CodeIgniter, the first step is to load the email class within your controller:</p>
76
77<code>$this->load->library('email');</code>
78
Derek Allard8d027fa2010-07-05 07:47:38 -0400[diff] [blame]79<p>Once loaded, the library will be ready for use, using <kbd>$this->email-></kbd><samp><em>some_function</em>()</samp>.</p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]80
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]81<p>Library files can be stored in subdirectories within the main "libraries" folder, or within your personal <dfn>application/libraries</dfn> folder.
82To load a file located in a subdirectory, simply include the path, relative to the "libraries" folder.
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]83For example, if you have file located at:</p>
84
85<code>libraries/flavors/chocolate.php</code>
86
87<p>You will load it using:</p>
88
89<code>$this->load->library('flavors/chocolate');</code>
90
91<p>You may nest the file in as many subdirectories as you want.</p>
92
93<h3>Setting options</h3>
94
95<p>The second (optional) parameter allows you to optionally pass configuration setting. You will typically pass these as an array:</p>
96
97<code>
98$config = array (<br />
99&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'mailtype' => 'html',<br />
100&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'charset'&nbsp; => 'utf-8,<br />
101&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'priority' => '1'<br />
102&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);<br />
103<br />
104$this->load->library('email', $config);</code>
105
106<p>Config options can usually also be set via a config file. Each library is explained in detail in its own page, so please read the information regarding each one you would like to use.</p>
107
108<h3>Assigning a Library to a different object name</h3>
109
110<p>If the third (optional) parameter is blank, the library will usually be assigned to an object with the same name as the library. For example, if the library is named <dfn>Session</dfn>, it
111will be assigned to a variable named <dfn>$this->session</dfn>.</p>
112
113<p>If you prefer to set your own class names you can pass its value to the third parameter:</p>
114
115<code>$this->load->library('session', '', 'my_session');<br /><br />
116
117// Session class is now accessed using:<br /><br />
118
119$this->my_session
120
121</code>
122
123
124
125<h2>$this->load->view('<var>file_name</var>', <samp>$data</samp>, <kbd>true/false</kbd>)</h2>
126
127<p>This function is used to load your View files. If you haven't read the <a href="../general/views.html">Views</a> section of the
128user guide it is recommended that you do since it shows you how this function is typically used.</p>
129
130<p>The first parameter is required. It is the name of the view file you would like to load. &nbsp;Note: The .php file extension does not need to be specified unless you use something other than <kbd>.php</kbd>.</p>
131
132<p>The second <strong>optional</strong> parameter can take
133an associative array or an object as input, which it runs through the PHP <a href="http://www.php.net/extract">extract</a> function to
134convert to variables that can be used in your view files. Again, read the <a href="../general/views.html">Views</a> page to learn
135how this might be useful.</p>
136
137<p>The third <strong>optional</strong> parameter lets you change the behavior of the function so that it returns data as a string
138rather than sending it to your browser. This can be useful if you want to process the data in some way. If you
139set the parameter to <kbd>true</kbd> (boolean) it will return data. The default behavior is <kbd>false</kbd>, which sends it
140to your browser. Remember to assign it to a variable if you want the data returned:</p>
141
142<code>$string = $this->load->view('<var>myfile</var>', '', <kbd>true</kbd>);</code>
143
144
145<h2>$this-&gt;load-&gt;model('<var>Model_name</var>');</h2>
146<p><code>$this-&gt;load-&gt;model('<var>Model_name</var>');</code></p>
147<p>If your model is located in a sub-folder, include the relative path from your models folder. For example, if you have a model located at application/models/blog/queries.php you'll load it using:</p>
148<p><code>$this-&gt;load-&gt;model('<var>blog/queries</var>');</code></p>
149<p>If you would like your model assigned to a different object name you can specify it via the second parameter of the loading
150 function:</p>
151<code> $this-&gt;load-&gt;model('<var>Model_name</var>', '<kbd>fubar</kbd>');<br />
152<br />
153$this-&gt;<kbd>fubar</kbd>-&gt;function();</code>
154<h2>$this->load->database('<var>options</var>', <kbd>true/false</kbd>)</h2>
155<p>This function lets you load the database class. The two parameters are <strong>optional</strong>. Please see the
Derek Allard3f45bbd2008-12-07 17:00:09 +0000[diff] [blame]156<a href="../database/index.html">database</a> section for more info.</p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]157
158
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]159
160
161<h2>$this->load->vars(<samp>$array</samp>)</h2>
162
163<p>This function takes an associative array as input and generates variables using the PHP <a href="http://www.php.net/extract">extract</a> function.
164This function produces the same result as using the second parameter of the <dfn>$this->load->view()</dfn> function above. The reason you might
165want to use this function independently is if you would like to set some global variables in the constructor of your controller
166and have them become available in any view file loaded from any function. You can have multiple calls to this function. The data get cached
167and merged into one array for conversion to variables.
168</p>
169
170
171<h2>$this->load->helper('<var>file_name</var>')</h2>
172<p>This function loads helper files, where <var>file_name</var> is the name of the file, without the <kbd>_helper.php</kbd> extension.</p>
173
174
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]175<h2>$this->load->file('<var>filepath/filename</var>', <kbd>true/false</kbd>)</h2>
176<p>This is a generic file loading function. Supply the filepath and name in the first parameter and it will open and read the file.
177By default the data is sent to your browser, just like a View file, but if you set the second parameter to <kbd>true</kbd> (boolean)
178it will instead return the data as a string.</p>
179
180
Derek Allardb5f211b2010-01-17 15:42:56 +0000[diff] [blame]181<h2>$this->load->language('<var>file_name</var>')</h2>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]182<p>This function is an alias of the <a href="language.html">language loading function</a>: $this->lang->load()</p>
183
184<h2>$this->load->config('<var>file_name</var>')</h2>
185<p>This function is an alias of the <a href="config.html">config file loading function</a>: $this->config->load()</p>
186
187
Derek Jones2ede2f62010-03-10 15:00:18 -0600[diff] [blame]188<h2>Application "Packages"</h2>
189
Derek Jonesf0b39942010-03-25 10:08:20 -0500[diff] [blame]190<p>An application package allows for the easy distribution of complete sets of resources in a single directory, complete with its own libraries, models, helpers, config, and language files. It is recommended that these packages be placed in the <dfn>application/third_party</dfn> folder. Below is a sample map of an package directory</p>
Derek Jones2ede2f62010-03-10 15:00:18 -0600[diff] [blame]191
192
193<h2>Sample Package "Foo Bar" Directory Map</h2>
194
195<p>The following is an example of a directory for an application package named "Foo Bar".</p>
196
Derek Jonesf0b39942010-03-25 10:08:20 -0500[diff] [blame]197<code>/application/third_party/foo_bar<br />
Derek Jones2ede2f62010-03-10 15:00:18 -0600[diff] [blame]198<br />
199config/<br />
200helpers/<br />
201language/<br />
202libraries/<br />
203models/<br />
204</code>
205
206<p>Whatever the purpose of the "Foo Bar" application package, it has its own config files, helpers, language files, libraries, and models. To use these resources in your controllers, you first need to tell the Loader that you are going to be loading resources from a package, by adding the package path.</p>
207
208<h3>$this->load->add_package_path()</h3>
209
210<p>Adding a package path instructs the Loader class to prepend a given path for subsequent requests for resources. As an example, the "Foo Bar" application package above has a library named <dfn>Foo_bar.php</dfn>. In our controller, we'd do the following:</p>
211
212<code>$this->load->add_package_path(<var>APPPATH</var>.'third_party/<var>foo_bar</var>/');<br />
213$this->load->library('foo_bar');</code>
214
215<h3>$this->load->remove_package_path()</h3>
216
217<p>When your controller is finished using resources from an application package, and particularly if you have other application packages you want to work with, you may wish to remove the package path so the Loader no longer looks in that folder for resources. To remove the last path added, simply call the method with no parameters.</p>
218
219<h3>$this->load->remove_package_path()</h3>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]220
Derek Jones2ede2f62010-03-10 15:00:18 -0600[diff] [blame]221<p>Or to remove a specific package path, specify the same path previously given to <kbd>add_package_path() for a package.</kbd>:</p>
222
223<code>$this->load->remove_package_path(<var>APPPATH</var>.'third_party/<var>foo_bar</var>/');</code>
224
225<h3>Package view files</h3>
226
227<p>@todo - package view file interface is not complete. It can be experimentally used by first saving the Loader's original view path, setting the view path to the package's view path, and when finished, setting back to the original view path.</p>
228
229<code>// ... save the original view path, and set to our Foo Bar package view folder<br />
230$orig_view_path = $this->load->_ci_view_path;<br />
231$this->load->_ci_view_path = <var>APPPATH</var>.'third_party/<var>foo_bar</var>/views/';<br />
232<br />
233// ... code using the package's view files<br />
234<br />
235// ... then return the view path to the application's original view path<br />
236$this->load->_ci_view_path = $orig_view_path;</code>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]237
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