CodeIgniter Home
- What is CodeIgniter?
- Features of CodeIgniter
- Advantages over other PHP frameworks
- CodeIgniter version history
CodeIgniter Overview
- Key Components of CodeIgniter
- MVC design pattern explained
- Workflow of a CodeIgniter application
- System and Application folders overview
CodeIgniter Installing CodeIgniter
- System Requirements (PHP, MySQL, Extensions)
- Downloading & Extracting CodeIgniter
- Folder structure explained
- Setting base URL
- Configuring index.php file
- Running first application
CodeIgniter Application Architecture
- Folder structure in detail
- Application vs System folders
- Config, Controllers, Models, Views
- Helpers and Libraries placement
- User Guide access
CodeIgniter MVC Framework
- Understanding MVC flow
- Codeigniter Creating Controllers
- Creating Views
- Creating Models
- Loading Models and Views
- Data flow between MVC components
CodeIgniter Basic Concepts
- URLs in CodeIgniter
- Default controller setup
- Routing basics
- Auto-loading resources
- Naming conventions
CodeIgniter Configuration
- Configuration files overview
- Base URL and Index page settings
- Encryption key setup
- Codeigniter Database configuration
- Error logging configuration
- Custom configuration files
CodeIgniter Working with Database
- Database configuration
- Loading database library
- Query Builder class
- Running queries (select, insert, update, delete)
- Active Record class
- Transactions
- Joins, Grouping, Ordering, Limit
- Query bindings
- Result handling (row(), result())
CodeIgniter Libraries
- Built-in libraries overview
- Loading libraries
- Common libraries: Pagination, Upload, Email, Form Validation, Session, Encryption, Calendar
- Creating custom libraries
CodeIgniter Error Handling
- Error reporting levels
- Custom error pages (404, 500)
- Using log_message()
- Displaying errors in development vs production
CodeIgniter File Uploading
- Upload library setup
- File upload configuration (path, allowed types, max size)
- Handling errors in upload
- Multiple file uploads
- Securing uploads
CodeIgniter Sending Email
- Email library configuration
- Sending emails via SMTP
- Sending attachments
- Sending HTML emails
- Debugging email errors
CodeIgniter Form Validation
- Form validation library overview
- Setting validation rules
- Prepping data before validation
- Error messages customization
- Validation callbacks
- Server-side vs Client-side validation
CodeIgniter Session Management
- Session library configuration
- Storing session data
- Retrieving session data
- Flashdata in sessions
- Database-driven sessions
CodeIgniter Flashdata
- What is Flashdata?
- Creating flashdata messages
- Retrieving flashdata
- Flashdata expiration
CodeIgniter Tempdata
- Difference between flashdata & tempdata
- Creating tempdata
- Retrieving tempdata
- Removing tempdata
CodeIgniter Cookie Management
- Setting cookies
- Retrieving cookies
- Deleting cookies
- Cookie security
CodeIgniter Common Functions
- base_url()
- site_url()
- redirect()
- form_open() & form helper functions
- String helper functions
CodeIgniter Page Caching
- Enabling page caching
- Cache expiration
- Deleting cache files
- Best practices in caching
CodeIgniter Page Redirection
- Redirect helper function
- Permanent vs Temporary redirection
- Redirect with flashdata
CodeIgniter Application Profiling
- Enabling profiler
- Profiler sections (benchmarks, queries, post data, etc.)
- Customizing profiler output
CodeIgniter Benchmarking
- Benchmark class usage
- Measuring script execution time
- Measuring memory usage
- Custom benchmarks
CodeIgniter Adding JS and CSS
- Loading assets in views
- Using base_url() for assets
- Best practices for assets organization
- Versioning assets
CodeIgniter Internationalization
- Language files in CodeIgniter
- Loading language files
- Switching languages dynamically
- Multi-language website structure
CodeIgniter Security
- Input filtering and XSS cleaning
- CSRF protection
- SQL Injection prevention
- Password hashing & encryption
- Secure file uploads
- Using HTTPS with CodeIgniter

URLs in CodeIgniter

Last modified on: September 9, 2025

<h1 data-start="438" data-end="464">📝 URLs in CodeIgniter</h1>
<h2 data-start="466" data-end="486">🔎 Introduction</h2>
<p data-start="487" data-end="732">In CodeIgniter, <strong data-start="503" data-end="539">URLs (Uniform Resource Locators)</strong> determine how users access your controllers and methods.<br data-start="596" data-end="599" />By default, CodeIgniter uses a <strong data-start="630" data-end="661">segment-based URL structure</strong>, making it easy to map URLs to controllers, methods, and parameters.</p>
<hr data-start="734" data-end="737" />
<h2 data-start="739" data-end="771">📂 1. Default URL Structure</h2>
<p data-start="773" data-end="818">The general format of a CodeIgniter URL is:</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>http://example.com/index.php/controller/method/parameter
</code></pre>
</div>
</div>
</div>
</div>
<ul data-start="886" data-end="1051">
<li data-start="886" data-end="940">
<p data-start="888" data-end="940"><strong data-start="888" data-end="902">controller</strong> &rarr; The name of the Controller class.</p>
</li>
<li data-start="941" data-end="993">
<p data-start="943" data-end="993"><strong data-start="943" data-end="953">method</strong> &rarr; The function inside the Controller.</p>
</li>
<li data-start="994" data-end="1051">
<p data-start="996" data-end="1051"><strong data-start="996" data-end="1009">parameter</strong> &rarr; Optional values passed to the method.</p>
</li>
</ul>
<h3 data-start="1053" data-end="1066">Example</h3>
<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>http://example.com/index.php/products/detail/5
</code></pre>
</div>
</div>
</div>
</div>
<ul data-start="1123" data-end="1201">
<li data-start="1123" data-end="1153">
<p data-start="1125" data-end="1153"><strong data-start="1125" data-end="1140">Controller:</strong> <code data-start="1141" data-end="1151">Products</code></p>
</li>
<li data-start="1154" data-end="1178">
<p data-start="1156" data-end="1178"><strong data-start="1156" data-end="1167">Method:</strong> <code data-start="1168" data-end="1176">detail</code></p>
</li>
<li data-start="1179" data-end="1201">
<p data-start="1181" data-end="1201"><strong data-start="1181" data-end="1195">Parameter:</strong> <code data-start="1196" data-end="1199">5</code></p>
</li>
</ul>
<hr data-start="1203" data-end="1206" />
<h2 data-start="1208" data-end="1248">📂 2. Removing <code data-start="1226" data-end="1237">index.php</code> from URL</h2>
<p data-start="1250" data-end="1346">By default, <code data-start="1262" data-end="1273">index.php</code> appears in every CodeIgniter URL. You can remove it using <code data-start="1332" data-end="1343">.htaccess</code>.</p>
<h3 data-start="1348" data-end="1376">.htaccess (for Apache)</h3>
<p data-start="1377" data-end="1419">Place this file in your <strong data-start="1401" data-end="1416">root folder</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>&lt;IfModule mod_rewrite.c&gt;
    RewriteEngine On
    RewriteBase /

RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^(.*)$ index.php/$1 [L]
&lt;/IfModule&gt;
</code></pre>
</div>
</div>
</div>
</div>
<p data-start="1633" data-end="1667">👉 After this, your URL becomes:</p>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>http://example.com/products/detail/5
</code></pre>
</div>
</div>
</div>
</div>
<hr data-start="1714" data-end="1717" />
<h2 data-start="1719" data-end="1751">📂 3. Routes in CodeIgniter</h2>
<p data-start="1753" data-end="1804">You can customize URLs using the <strong data-start="1786" data-end="1801">Routes file</strong>.</p>
<ul data-start="1806" data-end="1907">
<li data-start="1806" data-end="1852">
<p data-start="1808" data-end="1852"><strong data-start="1808" data-end="1826">CodeIgniter 4:</strong> <code data-start="1827" data-end="1850">app/Config/Routes.php</code></p>
</li>
<li data-start="1853" data-end="1907">
<p data-start="1855" data-end="1907"><strong data-start="1855" data-end="1873">CodeIgniter 3:</strong> <code data-start="1874" data-end="1905">application/config/routes.php</code></p>
</li>
</ul>
<h3 data-start="1909" data-end="1928">Example Route</h3>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>$routes-&gt;get('shop/(:num)', 'Products::detail/$1');
</code></pre>
</div>
</div>
</div>
</div>
<p data-start="1993" data-end="2090">👉 This means:<br data-start="2007" data-end="2010" /><code data-start="2010" data-end="2037">http://example.com/shop/5</code> &rarr; Calls <code data-start="2046" data-end="2056">Products</code> controller &rarr; <code data-start="2070" data-end="2081">detail(5)</code> method</p>
<hr data-start="2092" data-end="2095" />
<h2 data-start="2097" data-end="2134">📂 4. Passing Parameters via URL</h2>
<h3 data-start="2136" data-end="2177">Controller Example (<code data-start="2160" data-end="2174">Products.php</code>)</h3>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>class Products extends BaseController
{
    public function detail($id)
    {
        echo "Product ID: " . $id;
    }
}
</code></pre>
</div>
</div>
</div>
</div>
<p data-start="2311" data-end="2320">👉 URL:</p>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>http://example.com/products/detail/10
</code></pre>
</div>
</div>
</div>
</div>
<p data-start="2368" data-end="2381"><strong data-start="2368" data-end="2379">Output:</strong></p>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>Product ID: 10
</code></pre>
</div>
</div>
</div>
</div>
<hr data-start="2406" data-end="2409" />
<h2 data-start="2411" data-end="2437">📂 5. Generating URLs</h2>
<p data-start="2439" data-end="2484">Instead of hardcoding, use <strong data-start="2466" data-end="2481">URL Helpers</strong>.</p>
<h3 data-start="2486" data-end="2514">Load URL Helper (CI3):</h3>
<div class="contain-inline-size rounded-2xl relative bg-token-sidebar-surface-primary">
<div class="sticky top-9">
<div class="absolute end-0 bottom-0 flex h-9 items-center pe-2">
<div class="bg-token-bg-elevated-secondary text-token-text-secondary flex items-center gap-4 rounded-sm px-2 font-sans text-xs">
<pre class="language-php"><code>$this-&gt;load-&gt;helper('url');
</code></pre>
</div>
</div>
</div>
</div>
<h3 data-start="2555" data-end="2579">Usage (CI3 &amp; CI4):</h3>
<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>echo site_url('products/detail/5');
echo base_url('assets/css/style.css');
</code></pre>
</div>
</div>
</div>
</div>
<ul data-start="2667" data-end="2785">
<li data-start="2667" data-end="2711">
<p data-start="2669" data-end="2711"><strong data-start="2669" data-end="2685"><code data-start="2671" data-end="2683">base_url()</code></strong> &rarr; Returns site root URL</p>
</li>
<li data-start="2712" data-end="2785">
<p data-start="2714" data-end="2785"><strong data-start="2714" data-end="2730"><code data-start="2716" data-end="2728">site_url()</code></strong> &rarr; Returns URL with index.php (or without if removed)</p>
</li>
</ul>
<hr data-start="2787" data-end="2790" />
<h2 data-start="2792" data-end="2820">📂 6. SEO-Friendly URLs</h2>
<p data-start="2822" data-end="2866">To make CodeIgniter URLs <strong data-start="2847" data-end="2863">SEO-friendly</strong>:</p>
<ol data-start="2867" data-end="3229">
<li data-start="2867" data-end="2908">
<p data-start="2870" data-end="2908">Remove <code data-start="2877" data-end="2888">index.php</code> with <code data-start="2894" data-end="2905">.htaccess</code>.</p>
</li>
<li data-start="2909" data-end="3101">
<p data-start="2912" data-end="2954">Use <strong data-start="2916" data-end="2951">meaningful slugs instead of IDs</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>$routes-&gt;get('product/(:segment)', 'Products::detail/$1');
</code></pre>
</div>
</div>
</div>
</div>
<p data-start="3037" data-end="3101">👉 URL: <code data-start="3045" data-end="3074">/product/samsung-galaxy-s24</code> instead of <code data-start="3086" data-end="3098">/product/5</code>.</p>
</li>
<li data-start="3102" data-end="3166">
<p data-start="3105" data-end="3166">Keep URLs <strong data-start="3115" data-end="3143">lowercase and hyphenated</strong> (e.g., <code data-start="3151" data-end="3162">/about-us</code>).</p>
</li>
<li data-start="3167" data-end="3229">
<p data-start="3170" data-end="3229">Use <code data-start="3174" data-end="3186">routes.php</code> to <strong data-start="3190" data-end="3208">map clean URLs</strong> to actual methods.</p>
</li>
</ol>
<hr data-start="3231" data-end="3234" />
<h2 data-start="3236" data-end="3261">🎯 7. Best Practices</h2>
<ul data-start="3263" data-end="3534">
<li data-start="3263" data-end="3312">
<p data-start="3265" data-end="3312">Always <strong data-start="3272" data-end="3294">remove <code data-start="3281" data-end="3292">index.php</code></strong> for clean URLs.</p>
</li>
<li data-start="3313" data-end="3373">
<p data-start="3315" data-end="3373">Use <strong data-start="3319" data-end="3329">routes</strong> for user-friendly and SEO-friendly paths.</p>
</li>
<li data-start="3374" data-end="3419">
<p data-start="3376" data-end="3419">Prefer <strong data-start="3383" data-end="3392">slugs</strong> over IDs in public URLs.</p>
</li>
<li data-start="3420" data-end="3460">
<p data-start="3422" data-end="3460">Keep URLs <strong data-start="3432" data-end="3457">short and descriptive</strong>.</p>
</li>
<li data-start="3461" data-end="3534">
<p data-start="3463" data-end="3534">Always use <code data-start="3474" data-end="3486">base_url()</code> and <code data-start="3491" data-end="3503">site_url()</code> instead of hardcoding links.</p>
</li>
</ul>
<hr data-start="3536" data-end="3539" />
<h2 data-start="3541" data-end="3561">✅ 8. Conclusion</h2>
<ul data-start="3563" data-end="3746">
<li data-start="3563" data-end="3631">
<p data-start="3565" data-end="3631">URLs in CodeIgniter map directly to <strong data-start="3601" data-end="3628">Controllers and Methods</strong>.</p>
</li>
<li data-start="3632" data-end="3676">
<p data-start="3634" data-end="3676">You can customize them using <strong data-start="3663" data-end="3673">routes</strong>.</p>
</li>
<li data-start="3677" data-end="3746">
<p data-start="3679" data-end="3746">With <code data-start="3684" data-end="3695">.htaccess</code>, you can create <strong data-start="3712" data-end="3743">clean and SEO-friendly URLs</strong>.</p>
</li>
</ul>
<p data-start="3748" data-end="3857"><strong data-start="3748" data-end="3765">Flow Example:</strong><br data-start="3765" data-end="3768" />👉 <code data-start="3771" data-end="3791">/products/detail/5</code> &rarr; Controller <code data-start="3805" data-end="3815">Products</code> &rarr; Method <code data-start="3825" data-end="3838">detail($id)</code> &rarr; Output in View</p>

Web Technology View More