# Polymorphic Record Sharing + Authorization System

This document describes the implementation of a comprehensive authorization system using CASL, Objection.js, and NestJS.

## Overview

The system supports:
- **Global object policies** - Public/private access, default permissions per object type
- **Role-based access** - Permissions assigned to roles, with CASL rule storage
- **Per-record sharing** - Polymorphic sharing where owners can grant specific users access to individual records
- **Field-level permissions** - Fine-grained control over which fields can be read/written

## Architecture

### Database Schema

#### `object_definitions` (Enhanced)
- `accessModel`: 'public' | 'owner' | 'mixed'
- `publicRead/Create/Update/Delete`: Boolean flags for public access
- `ownerField`: Field name storing record owner (default: 'ownerId')

#### `field_definitions` (Enhanced)
- `defaultReadable`: Boolean - Can this field be read by default
- `defaultWritable`: Boolean - Can this field be written by default

These permission flags are added directly to the existing `field_definitions` table, keeping all field metadata in one place.

#### `role_rules` (New)
- `roleId`: FK to roles
- `rulesJson`: JSON array of CASL rules

#### `record_shares` (New)
Polymorphic sharing table:
- `objectDefinitionId`: FK to object_definitions
- `recordId`: String (supports UUID/int)
- `granteeUserId`: User receiving access
- `grantedByUserId`: User granting access
- `actions`: JSON array of actions ["read", "update", etc.]
- `fields`: Optional JSON array of field names
- `expiresAt/revokedAt`: Optional expiry and revocation timestamps

### Backend Components

#### AbilityFactory (`src/auth/ability.factory.ts`)
Builds CASL abilities from three layers:
1. **Global rules** - From object_definitions and object_fields
2. **Role rules** - From role_rules.rulesJson
3. **Share rules** - From record_shares for the user

```typescript
const ability = await abilityFactory.buildForUser(user, knex);
if (ability.can('read', 'Post')) {
  // User can read posts
}
```

#### Query Scoping (`src/auth/query-scope.util.ts`)
SQL-level filtering for list queries:

```typescript
import { applyReadScope } from '@/auth/query-scope.util';

const query = Post.query(knex);
applyReadScope(query, user, objectDefinition, knex);
// Query now only returns records user can access
```

Logic:
1. If `publicRead` is true → allow all
2. Else → owner OR valid share exists

#### Guards & Decorators
- `AbilitiesGuard` - Checks CASL abilities on routes
- `@CheckAbility()` - Decorator to require specific permissions
- `@CurrentUser()` - Inject current user
- `@CurrentAbility()` - Inject CASL ability

#### Controllers

**ShareController** (`src/rbac/share.controller.ts`)
- `POST /shares` - Create a share
- `GET /shares/record/:objectDefinitionId/:recordId` - List shares for a record
- `GET /shares/granted` - List shares granted by current user
- `GET /shares/received` - List shares received by current user
- `PATCH /shares/:id` - Update a share
- `DELETE /shares/:id` - Revoke a share

**RoleController** (`src/rbac/role.controller.ts`)
- Standard CRUD for roles
- `RoleRuleController` manages CASL rules per role

**ObjectAccessController** (`src/object/object-access.controller.ts`)
- `GET /setup/objects/:apiName/access` - Get access config
- `PUT /setup/objects/:apiName/access` - Update access model
- `POST /setup/objects/:apiName/fields/:fieldKey/permissions` - Set field permissions
- `PUT /setup/objects/:apiName/field-permissions` - Bulk update field permissions

### Frontend Components

#### ObjectAccessSettings (`components/ObjectAccessSettings.vue`)
Integrated into object management page as "Access & Permissions" tab:
- Configure access model (public/owner/mixed)
- Set public CRUD permissions
- Configure owner field
- Set default read/write permissions per field

#### RecordShareDialog (`components/RecordShareDialog.vue`)
Dialog for sharing individual records:
- List current shares
- Add new share with user email
- Select read/update permissions
- Optional field-level scoping
- Optional expiration date
- Revoke shares

#### Role Management (`pages/setup/roles.vue`)
Complete role management interface:
- List all roles
- Create new roles
- Delete roles
- Edit role permissions

#### RolePermissionsEditor (`components/RolePermissionsEditor.vue`)
Granular permission editor:
- Configure CRUD permissions per object type
- Apply conditions (e.g., "ownerId = $userId")
- Field-level restrictions (future)

## Usage Examples

### 1. Set Object to Owner-Only Access

```typescript
await api.put('/setup/objects/Post/access', {
  accessModel: 'owner',
  publicRead: false,
  ownerField: 'ownerId'
});
```

### 2. Share a Record

```typescript
await api.post('/shares', {
  objectDefinitionId: 'abc-123',
  recordId: 'post-456',
  granteeUserId: 'user-789',
  actions: ['read', 'update'],
  fields: ['title', 'body'], // Optional field scoping
  expiresAt: '2025-12-31T23:59:59Z' // Optional expiry
});
```

### 3. Create Role with Permissions

```typescript
// Create role
const role = await api.post('/roles', {
  name: 'Account Manager',
  description: 'Can manage accounts'
});

// Set permissions
await api.post('/role-rules', {
  roleId: role.id,
  rulesJson: [
    {
      action: ['read', 'update'],
      subject: 'Account',
      conditions: { ownerId: '$userId' } // Only own accounts
    },
    {
      action: ['read'],
      subject: 'Contact' // Can read all contacts
    }
  ]
});
```

### 4. Query with Authorization

```typescript
// In a controller
async getRecords(user: User) {
  const objectDef = await ObjectDefinition.query(this.knex)
    .findOne({ apiName: 'Post' });
  
  const query = Post.query(this.knex);
  applyReadScope(query, user, objectDef, this.knex);
  
  return query; // Only returns records user can read
}
```

### 5. Check Instance Permission

```typescript
// With CASL
const post = await Post.query().findById(id);
if (ability.can('update', subject(post, 'Post'))) {
  // User can update this post
}
```

## Migration Guide

1. **Run Migration**
   ```bash
   npm run migrate:latest
   ```

2. **Update Existing Objects**
   Set default access model for existing object types:
   ```sql
   UPDATE object_definitions 
   SET access_model = 'owner', 
       owner_field = 'ownerId'
   WHERE access_model IS NULL;
   ```

3. **Update Controllers**
   Add query scoping to list endpoints:
   ```typescript
   import { applyReadScope } from '@/auth/query-scope.util';
   
   // Before
   const records = await MyModel.query();
   
   // After
   const records = await applyReadScope(
     MyModel.query(),
     user,
     objectDef,
     knex
   );
   ```

4. **Add Guards**
   Protect routes with ability checks:
   ```typescript
   @UseGuards(JwtAuthGuard, AbilitiesGuard)
   @CheckAbility({ action: 'read', subject: 'Post' })
   async findAll() {
     // ...
   }
   ```

## Security Considerations

1. **Always use SQL scoping for lists** - Don't rely on post-fetch filtering
2. **Validate share ownership** - Only grantor can update/revoke shares
3. **Check expiry and revocation** - Filter out invalid shares in queries
4. **Field-level filtering** - Strip unauthorized fields from request bodies
5. **Tenant isolation** - All queries should be scoped to current tenant (if multi-tenant)

## Testing

### Unit Tests
Test ability building:
```typescript
it('should allow owner to read their records', async () => {
  const ability = await abilityFactory.buildForUser(user, knex);
  const post = { id: '123', ownerId: user.id };
  expect(ability.can('read', subject(post, 'Post'))).toBe(true);
});
```

### Integration Tests
Test query scoping:
```typescript
it('should only return owned records', async () => {
  const query = Post.query(knex);
  applyReadScope(query, user, objectDef, knex);
  const records = await query;
  
  expect(records.every(r => r.ownerId === user.id)).toBe(true);
});
```

## Future Enhancements

- [ ] Group/team sharing (share with multiple users)
- [ ] Public link sharing (token-based)
- [ ] Audit log for shares
- [ ] Share templates
- [ ] Cascading shares (share related records)
- [ ] Time-limited shares with auto-expiry
- [ ] Share approval workflow
- [ ] Delegation (share on behalf of another user)

## API Reference

See individual controller files for detailed API documentation:
- [ShareController](./backend/src/rbac/share.controller.ts)
- [RoleController](./backend/src/rbac/role.controller.ts)
- [ObjectAccessController](./backend/src/object/object-access.controller.ts)