Page Caching in CodeIgniter is a simple way to improve performance and speed of your website.

When caching is enabled, CodeIgniter saves the output of a page request as a static file.

Next time when the same page is requested, CodeIgniter will serve the cached version instead of processing the entire controller and database queries again.

This reduces:

• Database load
• Server processing time
• Page load time

🔹 How Page Caching Works

1. You enable caching in your controller method.
2. The page output is saved as a cache file inside:

application/cache/

1. Next time the same page is requested, CodeIgniter serves the cached file.
2. After the cache expires, CodeIgniter will regenerate it automatically.

🔹 Enabling Page Caching

Use the cache() method in your controller:

class Welcome extends CI_Controller {

    public function index()
    {
        // Enable cache for 10 minutes
        $this->output->cache(10);

        $this->load->view('welcome_message');
    }
}

✅ Here, the page output will be cached for 10 minutes.

🔹 Clearing Cache for a Page

To clear cache for a specific URL, you can manually delete the cache files inside:

application/cache/

Or use helper functions (in CI3 you often write a custom function for cache removal). Example:

$this->output->delete_cache('welcome/index');

🔹 Cache File Location

Cached files are stored in:

application/cache/

Make sure this folder is writable by the server.

🔹 Things to Remember

• Page caching works per URL.
• If you pass query strings like ?id=1 and ?id=2, they will generate different cache files.
• Don’t use caching for dynamic pages like user dashboards or shopping carts.
• Best used for static content pages like blog articles, about us, contact pages, etc.

Example: Caching a Blog Page

class Blog extends CI_Controller {

    public function article($id)
    {
        // Cache for 30 minutes
        $this->output->cache(30);

        $data['article'] = $this->db->get_where('articles', ['id' => $id])->row();
        $this->load->view('blog_view', $data);
    }
}

👉 Now, when a user visits the blog page, it will be cached for 30 minutes.