---
name: model-fetch
description: Loading model data from JavaScript using Model.fetch() with secure opt-in, authorization, and lazy relationships. Use when implementing fetch() methods on models, loading records from JavaScript, accessing relationships via await, or understanding the Ajax_Endpoint_Model_Fetch attribute.
---

# RSX Model Fetch System

## Overview

RSX allows JavaScript to securely access ORM models through explicit opt-in. Unlike Laravel's API routes which can expose all fields, RSX requires each model to implement its own `fetch()` method with authorization and data filtering.

---

## Security Model

- **Explicit Opt-In**: Models must implement `fetch()` with `#[Ajax_Endpoint_Model_Fetch]`
- **No Default Access**: No models are fetchable by default
- **Individual Authorization**: Each model controls who can fetch its records
- **Data Filtering**: Complete control over what data JavaScript receives

---

## Implementing fetch()

### Basic Implementation

```php
use Ajax_Endpoint_Model_Fetch;

class Product_Model extends Rsx_Model_Abstract
{
    #[Ajax_Endpoint_Model_Fetch]
    public static function fetch($id)
    {
        // Authorization check
        if (!Session::is_logged_in()) {
            return false;
        }

        // Fetch single record
        $model = static::find($id);
        return $model ?: false;
    }
}
```

### With Data Filtering

```php
#[Ajax_Endpoint_Model_Fetch]
public static function fetch($id)
{
    if (!Session::is_logged_in()) {
        return false;
    }

    $user = static::find($id);
    if (!$user) {
        return false;
    }

    // Remove sensitive fields
    unset($user->password_hash);
    unset($user->remember_token);

    return $user;
}
```

### With Authorization Check

```php
#[Ajax_Endpoint_Model_Fetch]
public static function fetch($id)
{
    $current_user = Session::get_user();
    if (!$current_user) {
        return false;
    }

    $order = static::find($id);
    if (!$order) {
        return false;
    }

    // Only allow access to own orders or admin users
    if ($order->user_id !== $current_user->id && !$current_user->is_admin) {
        return false;
    }

    return $order;
}
```

### Augmented Array Return (Computed Fields)

```php
#[Ajax_Endpoint_Model_Fetch]
public static function fetch($id)
{
    if (!Session::is_logged_in()) {
        return false;
    }

    $contact = static::find($id);
    if (!$contact) {
        return false;
    }

    // Start with toArray() to preserve __MODEL for hydration
    $data = $contact->toArray();

    // Add computed fields
    $data['full_name'] = $contact->full_name();
    $data['avatar_url'] = $contact->get_avatar_url();

    return $data;
}
```

**Important**: Always use `toArray()` as the base - it preserves `__MODEL` for JavaScript hydration.

---

## JavaScript Usage

### Fetch Single Record

```javascript
// Throws if not found
const project = await Project_Model.fetch(123);
console.log(project.name);

// Returns null if not found
const maybe = await Project_Model.fetch_or_null(999);
if (maybe) {
    console.log(maybe.name);
}
```

### Enum Properties (BEM-Style)

```javascript
const project = await Project_Model.fetch(1);

// Instance properties (from fetched data)
console.log(project.status_id__label);  // "Active"
console.log(project.status_id__badge);  // "bg-success"

// Static constants
if (project.status_id === Project_Model.STATUS_ACTIVE) {
    // ...
}
```

---

## Lazy Relationships

Relationships can be loaded on-demand from JavaScript. The related model must also implement `fetch()` with `#[Ajax_Endpoint_Model_Fetch]`.

### belongsTo Relationship

```php
// In Project_Model
#[Ajax_Endpoint_Model_Fetch]
public function client()
{
    return $this->belongsTo(Client_Model::class);
}
```

```javascript
const project = await Project_Model.fetch(123);
const client = await project.client();  // Returns Client_Model or null
console.log(client.name);
```

### hasMany Relationship

```php
// In Project_Model
#[Ajax_Endpoint_Model_Fetch]
public function tasks()
{
    return $this->hasMany(Task_Model::class);
}
```

```javascript
const project = await Project_Model.fetch(123);
const tasks = await project.tasks();  // Returns Task_Model[]
for (const task of tasks) {
    console.log(task.title);
}
```

### morphTo Relationship

```php
// In Activity_Model
#[Ajax_Endpoint_Model_Fetch]
public function subject()
{
    return $this->morphTo();
}
```

```javascript
const activity = await Activity_Model.fetch(1);
const subject = await activity.subject();  // Returns polymorphic model
```

---

## Return Value Rules

| Return | Meaning |
|--------|---------|
| Model object | Serialized via `toArray()`, includes `__MODEL` for hydration |
| Array (from `toArray()`) | Preserves `__MODEL`, can add computed fields |
| `false` | Record not found or unauthorized |

**MUST return `false`** (not `null`) when record is not found or unauthorized.

---

## Anti-Aliasing Policy

**NEVER alias enum properties in fetch()** - BEM-style naming exists for grepability:

```php
// WRONG - Aliasing obscures data source
$data['type_label'] = $record->type_id__label;

// RIGHT - Use full BEM-style names in JavaScript
contact.type_id__label  // Grepable, self-documenting
```

The `fetch()` method's purpose is **security** (removing private data), not aliasing.

---

## Common Patterns

### In SPA Action on_load()

```javascript
async on_load() {
    const project = await Project_Model.fetch(this.args.id);
    this.data.project = project;
}
```

### Loading with Relationships

```javascript
async on_load() {
    const project = await Project_Model.fetch(this.args.id);
    const [client, tasks] = await Promise.all([
        project.client(),
        project.tasks()
    ]);

    this.data.project = project;
    this.data.client = client;
    this.data.tasks = tasks;
}
```

### Conditional Relationship Loading

```javascript
async on_load() {
    const order = await Order_Model.fetch(this.args.id);
    this.data.order = order;

    // Only load customer if needed
    if (this.args.show_customer) {
        this.data.customer = await order.customer();
    }
}
```

## More Information

Details: `php artisan rsx:man model_fetch`