# Codeigniter

> Use when working with CodeIgniter 3 or CodeIgniter 4 applications — controllers, models, views, routing, database queries, migrations, libraries, helpers, security, file uploads, email, caching, testing, services, events, CLI commands, and deployment. Trigger on: CI3 projects with system/core/CodeIgniter.php or index.php bootstrapping CI, CI4 projects with app/Config/App.php or spark CLI, any men…

- **Type:** Skill
- **Install:** `agentstack add skill-yasserstudio-codeigniter-skills-codeigniter`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [yasserstudio](https://agentstack.voostack.com/s/yasserstudio)
- **Installs:** 0
- **Category:** [Databases](https://agentstack.voostack.com/c/databases)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [yasserstudio](https://github.com/yasserstudio)
- **Source:** https://github.com/yasserstudio/codeigniter-skills/tree/main/skills/codeigniter
- **Website:** https://github.com/yasserstudio/codeigniter-skills/releases/latest

## Install

```sh
agentstack add skill-yasserstudio-codeigniter-skills-codeigniter
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# CodeIgniter Development

You are a CodeIgniter expert. You work with both CI3 (3.1.x) and CI4 (4.x, latest stable 4.7.x) and understand their fundamental architectural differences. Always identify which version the project uses before writing any code.

For deep dives on version-specific features, see:
- [CI3 deep dive](references/ci3.md) — file uploads, email, caching, pagination, libraries, HMVC, hooks, helpers, logging
- [CI4 deep dive](references/ci4.md) — REST controllers, entities, filters, migrations, seeders, uploads, email, caching, services, events, views, cells, Spark CLI, testing, Shield auth, content negotiation
- [Deployment & migration](references/deployment.md) — server config, production checklist, full CI3→CI4 migration table

## Version Detection

| Signal | Version |
|--------|---------|
| `system/core/CodeIgniter.php` exists | CI3 |
| `$this->load->model()` / `$this->load->view()` | CI3 |
| `application/config/config.php` | CI3 |
| `app/Config/App.php` exists | CI4 |
| `namespace App\Controllers;` in controllers | CI4 |
| `spark` CLI at project root | CI4 |
| `composer.json` requires `codeigniter4/framework` | CI4 |

---

## CI3 — Core Patterns

### Project Structure

```
project/
├── application/
│   ├── config/        # autoload.php, config.php, database.php, routes.php, hooks.php
│   ├── controllers/
│   ├── models/
│   ├── views/
│   ├── libraries/
│   ├── helpers/
│   ├── hooks/
│   ├── core/          # MY_Controller, MY_Model overrides
│   └── third_party/
├── system/            # framework core — never edit
└── index.php          # front controller
```

### Controllers

```php
load->model('product_model');
        $this->load->helper('url');
    }

    public function index()
    {
        $data['products'] = $this->product_model->get_all();
        $this->load->view('products/index', $data);
    }

    public function view($id)
    {
        $data['product'] = $this->product_model->get($id);
        if (empty($data['product'])) {
            show_404();
        }
        $this->load->view('products/view', $data);
    }
}
```

**Rules:** Class name MUST match filename (first letter uppercase). Always call `parent::__construct()`. On Linux, filenames are case-sensitive.

### Models

```php
db->get($this->table)->result();
    }

    public function get($id)
    {
        return $this->db->get_where($this->table, ['id' => $id])->row();
    }

    public function insert($data)
    {
        $this->db->insert($this->table, $data);
        return $this->db->insert_id();
    }

    public function update($id, $data)
    {
        $this->db->where('id', $id);
        return $this->db->update($this->table, $data);
    }

    public function delete($id)
    {
        return $this->db->delete($this->table, ['id' => $id]);
    }
}
```

### Query Builder

```php
// SELECT with chaining
$results = $this->db
    ->select('p.*, c.name as category_name')
    ->from('products p')
    ->join('categories c', 'c.id = p.category_id', 'left')
    ->where('p.active', 1)
    ->where('p.price >', 10)
    ->order_by('p.name', 'ASC')
    ->limit(20, $offset)
    ->get()
    ->result();

// INSERT / UPDATE / DELETE
$this->db->insert('products', ['name' => $name, 'price' => $price]);
$this->db->where('id', $id)->update('products', ['price' => $new_price]);
$this->db->where('id', $id)->delete('products');

// Transactions
$this->db->trans_start();
$this->db->insert('orders', $order_data);
$this->db->insert('order_items', $item_data);
$this->db->trans_complete();
if ($this->db->trans_status() === FALSE) { /* failed */ }

// Raw query (always bind params)
$this->db->query('SELECT * FROM products WHERE slug = ?', [$slug]);
```

### Routing

```php
$route['default_controller'] = 'home';
$route['404_override'] = 'errors/page_missing';
$route['products'] = 'catalog/index';
$route['products/(:num)'] = 'catalog/view/$1';
$route['api/products/(:any)'] = 'api/products/$1';
```

### Input & Security

```php
// ALWAYS use $this->input — never raw $_POST/$_GET
$name = $this->input->post('name', TRUE);  // TRUE = XSS filter
$id   = $this->input->get('id');

// CSRF — enable in config.php
$config['csrf_protection'] = TRUE;

// Output escaping in views

```

### Form Validation

```php
$this->load->library('form_validation');
$this->form_validation->set_rules('name', 'Name', 'required|min_length[3]|max_length[255]');
$this->form_validation->set_rules('email', 'Email', 'required|valid_email|is_unique[users.email]');

if ($this->form_validation->run() === FALSE) {
    $this->load->view('form', $data);
} else {
    $this->product_model->insert($this->input->post());
    redirect('products');
}
```

### Sessions

```php
$this->session->set_userdata('user_id', $id);
$user_id = $this->session->userdata('user_id');
$this->session->set_flashdata('success', 'Product created.');
```

---

## CI4 — Core Patterns

### Project Structure

```
project/
├── app/
│   ├── Config/        # App.php, Database.php, Routes.php, Filters.php, Services.php, Events.php
│   ├── Controllers/   # BaseController.php
│   ├── Models/
│   ├── Views/
│   ├── Filters/
│   ├── Entities/
│   ├── Cells/
│   ├── Commands/
│   ├── Database/      # Migrations/, Seeds/
│   └── Language/
├── public/            # web root — point server here
│   └── index.php
├── writable/          # cache, logs, session — must be writable by web server
├── tests/
├── .env
├── spark              # CLI tool
└── composer.json
```

### Controllers

```php
 $model->findAll()]);
    }

    public function show($id = null)
    {
        $product = model('ProductModel')->find($id);
        if ($product === null) {
            throw \CodeIgniter\Exceptions\PageNotFoundException::forPageNotFound();
        }
        return view('products/show', ['product' => $product]);
    }

    public function create()
    {
        if (! $this->validate([
            'name'  => 'required|min_length[3]|max_length[255]',
            'price' => 'required|numeric|greater_than[0]',
        ])) {
            return view('products/create', ['validation' => $this->validator]);
        }
        model('ProductModel')->insert($this->request->getPost());
        return redirect()->to('/products')->with('success', 'Product created.');
    }
}
```

### Models

```php
 'required|min_length[3]|max_length[255]',
        'price' => 'required|numeric|greater_than[0]',
    ];
}
```

**Critical:** `$allowedFields` is mandatory — fields not listed are silently dropped on insert/update. This prevents mass assignment.

### Query Builder

```php
$db = db_connect();

// SELECT with joins + pagination
$model = model('ProductModel');
$data = [
    'products' => $model->where('active', 1)->paginate(20),
    'pager'    => $model->pager,
];

// Raw builder
$results = $db->table('products')
    ->select('products.*, categories.name as category')
    ->join('categories', 'categories.id = products.category_id', 'left')
    ->where('products.active', 1)
    ->orderBy('products.name', 'ASC')
    ->get()
    ->getResultArray();

// Transactions
$db->transStart();
$db->table('orders')->insert($order_data);
$db->table('order_items')->insert($item_data);
$db->transComplete();
if (! $db->transStatus()) { /* failed */ }
```

### Routing

```php
$routes->get('/', 'Home::index');
$routes->get('products', 'Products::index');
$routes->get('products/(:num)', 'Products::show/$1');
$routes->post('products', 'Products::create');
$routes->resource('products'); // generates all CRUD routes

$routes->group('api', ['namespace' => 'App\Controllers\Api', 'filter' => 'apiauth'], function ($routes) {
    $routes->resource('products');
});

$routes->get('admin/(:any)', 'Admin::$1', ['filter' => 'auth']);
```

### Input & Security

```php
// ALWAYS use $this->request — never raw $_POST/$_GET
$name = $this->request->getPost('name');
$id   = $this->request->getGet('id');
$data = $this->request->getJSON(true); // JSON API bodies → array

// Output escaping in views — context-aware

```

### Sessions

```php
$session = session();
$session->set('user_id', $id);
$userId = $session->get('user_id');
$session->setFlashdata('success', 'Done.');
$session->setTempdata('otp', $code, 300); // auto-expires in 5 minutes
```

---

## Security Checklist (Both Versions)

- [ ] Never use raw `$_POST`/`$_GET` — use input class (CI3) or `$this->request` (CI4)
- [ ] Enable CSRF protection; exempt only stateless API endpoints
- [ ] Use query builder or bound parameters — never concatenate SQL
- [ ] Escape output: `html_escape()` (CI3) or `esc()` (CI4) in views
- [ ] Set `db_debug = FALSE` (CI3) / `CI_ENVIRONMENT = production` (CI4) on prod
- [ ] Keep `system/` (CI3) or project root (CI4) outside web root
- [ ] Use `$allowedFields` in CI4 models to prevent mass assignment
- [ ] Validate file uploads — check MIME type, not just extension
- [ ] Set secure session config: `database` driver, `httponly`, `secure` flags
- [ ] Use `esc($var, 'attr')` for HTML attributes, `esc($var, 'js')` for JS contexts
- [ ] Set `Content-Security-Policy` headers for production
- [ ] Use HTTPS everywhere — `app.forceGlobalSecureRequests = true` in CI4
- [ ] Never expose stack traces in production

---

## CI3 → CI4 Quick Reference

| CI3 | CI4 |
|-----|-----|
| `$this->load->model('x')` | `model('XModel')` or DI |
| `$this->load->view('x', $data)` | `return view('x', $data)` |
| `$this->load->library('x')` | `service('x')` or `new X()` |
| `$this->input->post('x')` | `$this->request->getPost('x')` |
| `$this->db->get('table')` | `$db->table('table')->get()` |
| `$query->result()` / `->row()` | `$query->getResult()` / `->getRow()` |
| `$query->result_array()` | `$query->getResultArray()` |
| `redirect('url')` | `return redirect()->to('url')` |
| `show_404()` | `throw PageNotFoundException::forPageNotFound()` |
| `$this->session->userdata('x')` | `session()->get('x')` |
| `html_escape($x)` | `esc($x)` |
| `$route['x'] = 'y'` | `$routes->get('x', 'Y::method')` |
| Hooks (`$hook[]`) | Filters (middleware) |
| `CI_Controller` / `CI_Model` | `BaseController` / `CodeIgniter\Model` |
| No namespaces | PSR-4 namespaces |
| No CLI generator | `php spark make:*` |

See [deployment.md](references/deployment.md) for the full 30+ mapping migration table, server configuration, and production deployment checklist.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [yasserstudio](https://github.com/yasserstudio)
- **Source:** [yasserstudio/codeigniter-skills](https://github.com/yasserstudio/codeigniter-skills)
- **License:** MIT
- **Homepage:** https://github.com/yasserstudio/codeigniter-skills/releases/latest

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** yes
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-yasserstudio-codeigniter-skills-codeigniter
- Seller: https://agentstack.voostack.com/s/yasserstudio
- Browse the marketplace: https://agentstack.voostack.com/browse

---
Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.