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Helpers and Libraries placement

Last modified on: September 7, 2025

<h1 data-start="489" data-end="529">📝 CodeIgniter Helpers and Libraries</h1>
<h2 data-start="531" data-end="551">🔎 Introduction</h2>
<p data-start="552" data-end="655">CodeIgniter provides <strong data-start="573" data-end="584">Helpers</strong> and <strong data-start="589" data-end="602">Libraries</strong> to simplify common tasks and avoid rewriting code.</p>
<ul data-start="657" data-end="879">
<li data-start="657" data-end="752">
<p data-start="659" data-end="752"><strong data-start="659" data-end="671">Helpers:</strong> Collection of procedural functions for specific tasks (e.g., URL, form, text).</p>
</li>
<li data-start="753" data-end="879">
<p data-start="755" data-end="879"><strong data-start="755" data-end="769">Libraries:</strong> Classes that provide more advanced functionality and can maintain state (e.g., Email, Session, Encryption).</p>
</li>
</ul>
<p data-start="881" data-end="985">Knowing where to place them and how to use them is crucial for clean, reusable, and maintainable code.</p>
<hr data-start="987" data-end="990" />
<h2 data-start="992" data-end="1010">📂 1. Helpers</h2>
<h3 data-start="1012" data-end="1026">Purpose:</h3>
<p data-start="1027" data-end="1124">Helpers are <strong data-start="1039" data-end="1063">procedural functions</strong> that perform common tasks. They <strong data-start="1096" data-end="1121">do not maintain state</strong>.</p>
<h3 data-start="1126" data-end="1141">Location:</h3>
<ul data-start="1142" data-end="1277">
<li data-start="1142" data-end="1200">
<p data-start="1144" data-end="1200"><strong data-start="1144" data-end="1161">Core Helpers:</strong> <code data-start="1162" data-end="1179">system/Helpers/</code> (built-in helpers)</p>
</li>
<li data-start="1201" data-end="1277">
<p data-start="1203" data-end="1277"><strong data-start="1203" data-end="1222">Custom Helpers:</strong> <code data-start="1223" data-end="1237">app/Helpers/</code> (CI4) or <code data-start="1247" data-end="1269">application/helpers/</code> (CI3)</p>
</li>
</ul>
<h3 data-start="1279" data-end="1314">Examples of Built-in Helpers:</h3>
<ul data-start="1315" data-end="1515">
<li data-start="1315" data-end="1375">
<p data-start="1317" data-end="1375"><code data-start="1317" data-end="1329">url_helper</code> &rarr; Functions like <code data-start="1347" data-end="1359">base_url()</code>, <code data-start="1361" data-end="1373">site_url()</code></p>
</li>
<li data-start="1376" data-end="1440">
<p data-start="1378" data-end="1440"><code data-start="1378" data-end="1391">form_helper</code> &rarr; Functions like <code data-start="1409" data-end="1422">form_open()</code>, <code data-start="1424" data-end="1438">form_input()</code></p>
</li>
<li data-start="1441" data-end="1515">
<p data-start="1443" data-end="1515"><code data-start="1443" data-end="1456">text_helper</code> &rarr; Functions like <code data-start="1474" data-end="1490">word_limiter()</code>, <code data-start="1492" data-end="1513">character_limiter()</code></p>
</li>
</ul>
<h3 data-start="1517" data-end="1542">How to Load Helpers</h3>
<p data-start="1544" data-end="1554"><strong data-start="1544" data-end="1552">CI4:</strong></p>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
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<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>helper('url'); // Loads url_helper
echo base_url();
</code></pre>
</div>
</div>
</div>
</div>
<p data-start="1619" data-end="1629"><strong data-start="1619" data-end="1627">CI3:</strong></p>
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<div class="sticky top-9">
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<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>$this-&gt;load-&gt;helper('url');
echo base_url();
</code></pre>
</div>
</div>
</div>
</div>
<h3 data-start="1687" data-end="1717">Creating a Custom Helper</h3>
<ol data-start="1719" data-end="1816">
<li data-start="1719" data-end="1816">
<p data-start="1722" data-end="1816">Create a file <code data-start="1736" data-end="1763">app/Helpers/my_helper.php</code> (CI4) or <code data-start="1773" data-end="1808">application/helpers/my_helper.php</code> (CI3)</p>
</li>
</ol>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>&lt;?php
function greet($name) {
    return "Hello, " . $name;
}
</code></pre>
</div>
</div>
</div>
</div>
<ol start="2" data-start="1891" data-end="1926">
<li data-start="1891" data-end="1926">
<p data-start="1894" data-end="1926">Load the helper in Controller:</p>
</li>
</ol>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>helper('my_helper');
echo greet('John'); // Output: Hello, John
</code></pre>
</div>
</div>
</div>
</div>
<hr data-start="2003" data-end="2006" />
<h2 data-start="2008" data-end="2028">📂 2. Libraries</h2>
<h3 data-start="2030" data-end="2044">Purpose:</h3>
<p data-start="2045" data-end="2146">Libraries are <strong data-start="2059" data-end="2070">classes</strong> that provide advanced, reusable functionality and can <strong data-start="2125" data-end="2143">maintain state</strong>.</p>
<h3 data-start="2148" data-end="2163">Location:</h3>
<ul data-start="2164" data-end="2301">
<li data-start="2164" data-end="2218">
<p data-start="2166" data-end="2218"><strong data-start="2166" data-end="2185">Core Libraries:</strong> <code data-start="2186" data-end="2205">system/Libraries/</code> (built-in)</p>
</li>
<li data-start="2219" data-end="2301">
<p data-start="2221" data-end="2301"><strong data-start="2221" data-end="2242">Custom Libraries:</strong> <code data-start="2243" data-end="2259">app/Libraries/</code> (CI4) or <code data-start="2269" data-end="2293">application/libraries/</code> (CI3)</p>
</li>
</ul>
<h3 data-start="2303" data-end="2340">Examples of Built-in Libraries:</h3>
<ul data-start="2341" data-end="2475">
<li data-start="2341" data-end="2375">
<p data-start="2343" data-end="2375"><strong data-start="2343" data-end="2354">Session</strong> &rarr; <code data-start="2357" data-end="2373">$this-&gt;session</code></p>
</li>
<li data-start="2376" data-end="2406">
<p data-start="2378" data-end="2406"><strong data-start="2378" data-end="2387">Email</strong> &rarr; <code data-start="2390" data-end="2404">$this-&gt;email</code></p>
</li>
<li data-start="2407" data-end="2446">
<p data-start="2409" data-end="2446"><strong data-start="2409" data-end="2423">Encryption</strong> &rarr; <code data-start="2426" data-end="2444">$this-&gt;encrypter</code></p>
</li>
<li data-start="2447" data-end="2475">
<p data-start="2449" data-end="2475"><strong data-start="2449" data-end="2457">Cart</strong> &rarr; <code data-start="2460" data-end="2473">$this-&gt;cart</code></p>
</li>
</ul>
<h3 data-start="2477" data-end="2504">How to Load Libraries</h3>
<p data-start="2506" data-end="2516"><strong data-start="2506" data-end="2514">CI4:</strong></p>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>$email = \Config\Services::email(); // Loads Email Library
$email-&gt;setTo('user@example.com');
</code></pre>
</div>
</div>
</div>
</div>
<p data-start="2623" data-end="2633"><strong data-start="2623" data-end="2631">CI3:</strong></p>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>$this-&gt;load-&gt;library('email');
$this-&gt;email-&gt;from('me@example.com', 'Me');
$this-&gt;email-&gt;to('user@example.com');
$this-&gt;email-&gt;send();
</code></pre>
</div>
</div>
</div>
</div>
<h3 data-start="2781" data-end="2812">Creating a Custom Library</h3>
<ol data-start="2814" data-end="2915">
<li data-start="2814" data-end="2915">
<p data-start="2817" data-end="2915">Create a file <code data-start="2831" data-end="2860">app/Libraries/MyLibrary.php</code> (CI4) or <code data-start="2870" data-end="2907">application/libraries/MyLibrary.php</code> (CI3)</p>
</li>
</ol>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>&lt;?php
namespace App\Libraries;

class MyLibrary
{
    public function greet($name)
    {
        return "Hello, " . $name;
    }
}
</code></pre>
</div>
</div>
</div>
</div>
<ol start="2" data-start="3059" data-end="3097">
<li data-start="3059" data-end="3097">
<p data-start="3062" data-end="3097">Load and use in Controller (CI4):</p>
</li>
</ol>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>$lib = new \App\Libraries\MyLibrary();
echo $lib-&gt;greet('John'); // Output: Hello, John
</code></pre>
</div>
</div>
</div>
</div>
<p data-start="3198" data-end="3216"><strong data-start="3198" data-end="3214">CI3 Example:</strong></p>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>$this-&gt;load-&gt;library('MyLibrary');
echo $this-&gt;mylibrary-&gt;greet('John'); // Output: Hello, John
</code></pre>
</div>
</div>
</div>
</div>
<hr data-start="3325" data-end="3328" />
<h2 data-start="3330" data-end="3378">🔄 3. Key Differences: Helpers vs Libraries</h2>
<div class="_tableContainer_1rjym_1">
<div class="_tableWrapper_1rjym_13 group flex w-fit flex-col-reverse" tabindex="-1">
<table class="w-fit min-w-(--thread-content-width)" data-start="3380" data-end="3970">
<thead data-start="3380" data-end="3461">
<tr data-start="3380" data-end="3461">
<th data-start="3380" data-end="3400" data-col-size="sm">Feature</th>
<th data-start="3400" data-end="3427" data-col-size="sm">Helper</th>
<th data-start="3427" data-end="3461" data-col-size="md">Library</th>
</tr>
</thead>
<tbody data-start="3542" data-end="3970">
<tr data-start="3542" data-end="3624">
<td data-start="3542" data-end="3562" data-col-size="sm">Type</td>
<td data-start="3562" data-end="3589" data-col-size="sm">Procedural functions</td>
<td data-start="3589" data-end="3624" data-col-size="md">Class-based</td>
</tr>
<tr data-start="3625" data-end="3705">
<td data-start="3625" data-end="3645" data-col-size="sm">Maintains state</td>
<td data-start="3645" data-end="3671" data-col-size="sm">❌ No</td>
<td data-start="3671" data-end="3705" data-col-size="md">✅ Yes</td>
</tr>
<tr data-start="3706" data-end="3788">
<td data-start="3706" data-end="3726" data-col-size="sm">Location</td>
<td data-start="3726" data-end="3753" data-col-size="sm"><code data-start="3728" data-end="3742">app/Helpers/</code></td>
<td data-start="3753" data-end="3788" data-col-size="md"><code data-start="3755" data-end="3771">app/Libraries/</code></td>
</tr>
<tr data-start="3789" data-end="3887">
<td data-start="3789" data-end="3809" data-col-size="sm">Loading</td>
<td data-start="3809" data-end="3836" data-col-size="sm"><code data-start="3811" data-end="3827">helper('name')</code></td>
<td data-start="3836" data-end="3887" data-col-size="md"><code data-start="3838" data-end="3851">new Class()</code> or <code data-start="3855" data-end="3885">$this-&gt;load-&gt;library('name')</code></td>
</tr>
<tr data-start="3888" data-end="3970">
<td data-start="3888" data-end="3908" data-col-size="sm">Use case</td>
<td data-start="3908" data-end="3935" data-col-size="sm">Small, repetitive tasks</td>
<td data-start="3935" data-end="3970" data-col-size="md">Complex functionality</td>
</tr>
</tbody>
</table>
</div>
</div>
<hr data-start="3972" data-end="3975" />
<h2 data-start="3977" data-end="4002">🎯 4. Best Practices</h2>
<ol data-start="4004" data-end="4279">
<li data-start="4004" data-end="4044">
<p data-start="4007" data-end="4044"><strong data-start="4007" data-end="4042">Keep Helpers small and focused.</strong></p>
</li>
<li data-start="4045" data-end="4097">
<p data-start="4048" data-end="4097"><strong data-start="4048" data-end="4094">Place reusable classes in Libraries folder</strong>.</p>
</li>
<li data-start="4098" data-end="4222">
<p data-start="4101" data-end="4222"><strong data-start="4101" data-end="4145">Autoload commonly used Helpers/Libraries</strong> in <code data-start="4149" data-end="4170">Config/Autoload.php</code> (CI4) or <code data-start="4180" data-end="4213">application/config/autoload.php</code> (CI3).</p>
</li>
<li data-start="4223" data-end="4279">
<p data-start="4226" data-end="4279"><strong data-start="4226" data-end="4251">Use Namespaces in CI4</strong> to avoid class conflicts.</p>
</li>
</ol>
<hr data-start="4281" data-end="4284" />
<h2 data-start="4286" data-end="4303">✅ Conclusion</h2>
<ul data-start="4305" data-end="4568">
<li data-start="4305" data-end="4383">
<p data-start="4307" data-end="4383"><strong data-start="4307" data-end="4318">Helpers</strong> &rarr; Quick procedural functions for tasks like URLs, forms, text.</p>
</li>
<li data-start="4384" data-end="4483">
<p data-start="4386" data-end="4483"><strong data-start="4386" data-end="4399">Libraries</strong> &rarr; Class-based, maintain state, handle advanced operations like email or sessions.</p>
</li>
<li data-start="4484" data-end="4568">
<p data-start="4486" data-end="4502"><strong data-start="4486" data-end="4500">Placement:</strong></p>
<ul data-start="4505" data-end="4568">
<li data-start="4505" data-end="4533">
<p data-start="4507" data-end="4533">Helpers &rarr; <code data-start="4517" data-end="4531">app/Helpers/</code></p>
</li>
<li data-start="4536" data-end="4568">
<p data-start="4538" data-end="4568">Libraries &rarr; <code data-start="4550" data-end="4566">app/Libraries/</code></p>
</li>
</ul>
</li>
</ul>
<p data-start="4570" data-end="4691">Understanding Helpers and Libraries ensures <strong data-start="4614" data-end="4656">clean, reusable, and maintainable code</strong> in your CodeIgniter application.</p>

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