Laravel's Rule::contains() for Fluent Array Validation

Laravel's Rule::contains() method brings array validation into the fluent interface ecosystem, providing consistent syntax that matches other validation rules while improving code readability.

Previously, validating array contents required string concatenation and manual value handling:

'tags' => 'contains:' . implode(',', $allowedTags)

The new fluent approach eliminates string building and integrates seamlessly with Laravel's validation patterns.

use Illuminate\Validation\Rule;
 
'tags' => Rule::contains(['technology', 'programming', 'laravel'])

Here's a comprehensive content management system demonstrating various Rule::contains() applications:

class ContentController extends Controller
{
    public function store(Request $request)
    {
        $validator = Validator::make($request->all(), [
            'content_type' => [
                'required',
                'string',
                Rule::in(['article', 'tutorial', 'news', 'review'])
            ],
            'categories' => [
                'required',
                'array',
                'min:1',
                Rule::contains(['technology', 'business', 'lifestyle'])
            ],
            'permissions' => [
                'required',
                'array',
                Rule::contains([
                    Permission::READ->value,
                    Permission::WRITE->value
                ])
            ],
            'target_platforms' => [
                'sometimes',
                'array',
                Rule::contains(['web', 'mobile', 'api'])
            ],
            'notification_channels' => [
                'nullable',
                'array',
                Rule::contains(['email', 'sms', 'push', 'slack'])
            ]
        ]);
 
        if ($validator->fails()) {
            return response()->json(['errors' => $validator->errors()], 422);
        }
 
        $content = Content::create([
            'title' => $request->input('title'),
            'body' => $request->input('body'),
            'content_type' => $request->input('content_type'),
            'categories' => $request->input('categories'),
            'permissions' => $request->input('permissions'),
            'author_id' => auth()->id()
        ]);
 
        if ($request->has('target_platforms')) {
            $this->scheduleContentDistribution($content, $request->input('target_platforms'));
        }
 
        if ($request->has('notification_channels')) {
            $this->sendCreationNotifications($content, $request->input('notification_channels'));
        }
 
        return response()->json([
            'message' => 'Content created successfully',
            'content' => $content->load('author')
        ]);
    }
 
    public function updateSettings(Request $request)
    {
        $allowedThemes = ['light', 'dark', 'auto'];
        $allowedLanguages = ['en', 'es', 'fr', 'de', 'it'];
        $allowedNotifications = ['immediate', 'daily', 'weekly', 'monthly'];
 
        $validator = Validator::make($request->all(), [
            'user_preferences' => 'required|array',
            'user_preferences.themes' => [
                'required',
                'array',
                Rule::contains($allowedThemes)
            ],
            'user_preferences.languages' => [
                'required',
                'array',
                Rule::contains($allowedLanguages)
            ],
            'user_preferences.notification_frequency' => [
                'required',
                'array',
                Rule::contains($allowedNotifications)
            ],
            'admin_features' => [
                'sometimes',
                'array',
                Rule::contains([
                    AdminFeature::USER_MANAGEMENT->value,
                    AdminFeature::CONTENT_MODERATION->value,
                    AdminFeature::ANALYTICS_ACCESS->value
                ])
            ]
        ]);
 
        if ($validator->fails()) {
            return response()->json(['errors' => $validator->errors()], 422);
        }
 
        $user = auth()->user();
        $preferences = $request->input('user_preferences');
 
        $user->update([
            'preferences' => $preferences,
            'updated_at' => now()
        ]);
 
        if ($request->has('admin_features') && $user->isAdmin()) {
            $this->updateAdminPermissions($user, $request->input('admin_features'));
        }
 
        return response()->json([
            'message' => 'Settings updated successfully',
            'preferences' => $user->fresh()->preferences
        ]);
    }
 
    private function scheduleContentDistribution(Content $content, array $platforms)
    {
        foreach ($platforms as $platform) {
            ContentDistributionJob::dispatch($content, $platform)
                ->delay(now()->addMinutes(5));
        }
    }
 
    private function sendCreationNotifications(Content $content, array $channels)
    {
        foreach ($channels as $channel) {
            NotificationService::send($channel, new ContentCreatedNotification($content));
        }
    }
 
    private function updateAdminPermissions($user, array $features)
    {
        $user->adminPermissions()->sync($features);
    }
}
 
enum Permission: string
{
    case READ = 'read';
    case WRITE = 'write';
    case DELETE = 'delete';
    case PUBLISH = 'publish';
}
 
enum AdminFeature: string
{
    case USER_MANAGEMENT = 'user_management';
    case CONTENT_MODERATION = 'content_moderation';
    case ANALYTICS_ACCESS = 'analytics_access';
    case SYSTEM_SETTINGS = 'system_settings';
}

The Rule::contains() method maintains consistency with Laravel's validation ecosystem while providing cleaner, more maintainable array validation logic.