XOOPS Architecture¶

This document provides a comprehensive overview of the XOOPS system architecture, explaining how the various components work together to create a flexible and extensible content management system.

Overview¶

XOOPS follows a modular architecture that separates concerns into distinct layers. The system is built around several core principles:

• Modularity: Functionality is organized into independent, installable modules
• Extensibility: The system can be extended without modifying core code
• Abstraction: Database and presentation layers are abstracted from business logic
• Security: Built-in security mechanisms protect against common vulnerabilities

System Layers¶

graph TB
    subgraph Presentation["🎨 Presentation Layer"]
        Themes["Themes"]
        Templates["Smarty Templates"]
        Blocks["Blocks"]
    end

    subgraph Application["⚙️ Application Layer"]
        Modules["Modules"]
        Preloads["Preloads"]
        Controllers["Controllers"]
        BlockHandlers["Block Handlers"]
    end

    subgraph Domain["📦 Domain Layer"]
        XoopsObject["XoopsObject"]
        Handlers["Object Handlers"]
        Criteria["Criteria System"]
    end

    subgraph Infrastructure["🔧 Infrastructure Layer"]
        Database["XoopsDatabase"]
        Cache["Cache System"]
        Session["Session Manager"]
        Security["Security Layer"]
    end

    Presentation --> Application
    Application --> Domain
    Domain --> Infrastructure

    style Presentation fill:#e8f5e9,stroke:#388e3c
    style Application fill:#e3f2fd,stroke:#1976d2
    style Domain fill:#fff3e0,stroke:#f57c00
    style Infrastructure fill:#fce4ec,stroke:#c2185b

1. Presentation Layer¶

The presentation layer handles user interface rendering using the Smarty template engine.

Key Components: - Themes: Visual styling and layout - Smarty Templates: Dynamic content rendering - Blocks: Reusable content widgets

2. Application Layer¶

The application layer contains business logic, controllers, and module functionality.

Key Components: - Modules: Self-contained functionality packages - Handlers: Data manipulation classes - Preloads: Event listeners and hooks

3. Domain Layer¶

The domain layer contains core business objects and rules.

Key Components: - XoopsObject: Base class for all domain objects - Handlers: CRUD operations for domain objects

4. Infrastructure Layer¶

The infrastructure layer provides core services like database access and caching.

Request Lifecycle¶

Understanding the request lifecycle is crucial for effective XOOPS development.

XOOPS 2.5.x Page Controller Flow¶

The current XOOPS 2.5.x uses a Page Controller pattern where each PHP file handles its own request. Globals ($xoopsDB, $xoopsUser, $xoopsTpl, etc.) are initialized during bootstrap and available throughout execution.

sequenceDiagram
    participant Browser
    participant Entry as modules/mymod/index.php
    participant Main as mainfile.php
    participant Kernel as XOOPS Kernel
    participant DB as $xoopsDB
    participant User as $xoopsUser
    participant Handler as MyObjectHandler
    participant Tpl as $xoopsTpl (Smarty)
    participant Theme

    Browser->>Entry: GET /modules/mymod/index.php

    rect rgb(240, 248, 255)
        Note over Entry,User: Bootstrap Phase (mainfile.php)
        Entry->>Main: include mainfile.php
        Main->>Kernel: Initialize Core
        Kernel->>DB: Create XoopsDatabase (singleton)
        Kernel->>User: Load Session → $xoopsUser
        Kernel->>Tpl: Initialize Smarty → $xoopsTpl
        Main-->>Entry: Globals Ready
    end

    rect rgb(255, 250, 240)
        Note over Entry,Handler: Page Controller Execution
        Entry->>Handler: xoops_getModuleHandler('myobject')
        Handler->>DB: query via Criteria
        DB-->>Handler: Result Set
        Handler-->>Entry: XoopsObject[]
    end

    rect rgb(240, 255, 240)
        Note over Entry,Theme: Rendering Phase
        Entry->>Tpl: $xoopsTpl->assign('items', $objects)
        Entry->>Theme: include header.php
        Entry->>Tpl: $xoopsTpl->display('mymod_index.tpl')
        Entry->>Theme: include footer.php
        Theme-->>Browser: Complete HTML Page
    end

Key Globals in 2.5.x¶

1. Bootstrap Phase¶

// mainfile.php is the entry point
include_once XOOPS_ROOT_PATH . '/mainfile.php';

// Core initialization
$xoops = Xoops::getInstance();
$xoops->boot();

Steps: 1. Load configuration (mainfile.php) 2. Initialize autoloader 3. Set up error handling 4. Establish database connection 5. Load user session 6. Initialize Smarty template engine

2. Routing Phase¶

// Request routing to appropriate module
$module = $GLOBALS['xoopsModule'];
$controller = $module->getController();
$controller->dispatch($request);

Steps: 1. Parse request URL 2. Identify target module 3. Load module configuration 4. Check permissions 5. Route to appropriate handler

3. Execution Phase¶

// Controller execution
$data = $handler->getObjects($criteria);
$xoopsTpl->assign('items', $data);

Steps: 1. Execute controller logic 2. Interact with data layer 3. Process business rules 4. Prepare view data

4. Rendering Phase¶

// Template rendering
include XOOPS_ROOT_PATH . '/header.php';
$xoopsTpl->display('db:module_template.tpl');
include XOOPS_ROOT_PATH . '/footer.php';

Steps: 1. Apply theme layout 2. Render module template 3. Process blocks 4. Output response

Core Components¶

XoopsObject¶

The base class for all data objects in XOOPS.

<?php
class MyModuleItem extends XoopsObject
{
    public function __construct()
    {
        $this->initVar('id', XOBJ_DTYPE_INT, null, false);
        $this->initVar('title', XOBJ_DTYPE_TXTBOX, '', true, 255);
        $this->initVar('content', XOBJ_DTYPE_TXTAREA, '', false);
        $this->initVar('created', XOBJ_DTYPE_INT, time(), false);
    }
}

Key Methods: - initVar() - Define object properties - getVar() - Retrieve property values - setVar() - Set property values - assignVars() - Bulk assign from array

XoopsPersistableObjectHandler¶

Handles CRUD operations for XoopsObject instances.

<?php
class MyModuleItemHandler extends XoopsPersistableObjectHandler
{
    public function __construct(\XoopsDatabase $db)
    {
        parent::__construct($db, 'mymodule_items', 'MyModuleItem', 'id', 'title');
    }

    public function getActiveItems($limit = 10)
    {
        $criteria = new CriteriaCompo();
        $criteria->add(new Criteria('status', 1));
        $criteria->setSort('created');
        $criteria->setOrder('DESC');
        $criteria->setLimit($limit);

        return $this->getObjects($criteria);
    }
}

Key Methods: - create() - Create new object instance - get() - Retrieve object by ID - insert() - Save object to database - delete() - Remove object from database - getObjects() - Retrieve multiple objects - getCount() - Count matching objects

Module Structure¶

Every XOOPS module follows a standard directory structure:

modules/mymodule/
├── class/                  # PHP classes
│   ├── MyModuleItem.php
│   └── MyModuleItemHandler.php
├── include/                # Include files
│   ├── common.php
│   └── functions.php
├── templates/              # Smarty templates
│   ├── mymodule_index.tpl
│   └── mymodule_item.tpl
├── admin/                  # Admin area
│   ├── index.php
│   └── menu.php
├── language/               # Translations
│   └── english/
│       ├── main.php
│       └── modinfo.php
├── sql/                    # Database schema
│   └── mysql.sql
├── xoops_version.php       # Module info
├── index.php               # Module entry
└── header.php              # Module header

Dependency Injection Container¶

Modern XOOPS development can leverage dependency injection for better testability.

Basic Container Implementation¶

<?php
class XoopsDependencyContainer
{
    private array $services = [];

    public function register(string $name, callable $factory): void
    {
        $this->services[$name] = $factory;
    }

    public function resolve(string $name): mixed
    {
        if (!isset($this->services[$name])) {
            throw new \InvalidArgumentException("Service not found: $name");
        }

        $factory = $this->services[$name];

        if (is_callable($factory)) {
            return $factory($this);
        }

        return $factory;
    }

    public function has(string $name): bool
    {
        return isset($this->services[$name]);
    }
}

PSR-11 Compatible Container¶

<?php
namespace Xmf\Di;

use Psr\Container\ContainerInterface;

class BasicContainer implements ContainerInterface
{
    protected array $definitions = [];

    public function set(string $id, mixed $value): void
    {
        $this->definitions[$id] = $value;
    }

    public function get(string $id): mixed
    {
        if (!$this->has($id)) {
            throw new \InvalidArgumentException("Service not found: $id");
        }

        $entry = $this->definitions[$id];

        if (is_callable($entry)) {
            return $entry($this);
        }

        return $entry;
    }

    public function has(string $id): bool
    {
        return isset($this->definitions[$id]);
    }
}

Usage Example¶

<?php
// Service registration
$container = new XoopsDependencyContainer();

$container->register('database', function () {
    return XoopsDatabaseFactory::getDatabaseConnection();
});

$container->register('userHandler', function ($c) {
    return new XoopsUserHandler($c->resolve('database'));
});

// Service resolution
$userHandler = $container->resolve('userHandler');
$user = $userHandler->get($userId);

Extension Points¶

XOOPS provides several extension mechanisms:

1. Preloads¶

Preloads allow modules to hook into core events.

<?php
// modules/mymodule/preloads/core.php
class MymoduleCorePreload extends XoopsPreloadItem
{
    public static function eventCoreHeaderEnd($args)
    {
        // Execute when header processing ends
    }

    public static function eventCoreFooterStart($args)
    {
        // Execute when footer processing starts
    }
}

2. Plugins¶

Plugins extend specific functionality within modules.

<?php
// modules/mymodule/plugins/notify.php
class MymoduleNotifyPlugin
{
    public function onItemCreate($item)
    {
        // Send notification when item is created
    }
}

3. Filters¶

Filters modify data as it passes through the system.

<?php
// Content filter example
$myts = MyTextSanitizer::getInstance();
$content = $myts->displayTarea($rawContent, 1, 1, 1);

Best Practices¶

Code Organization¶

1. Use namespaces for new code:

   namespace XoopsModules\MyModule;
   
   class Item extends \XoopsObject
   {
       // Implementation
   }
   

2. Follow PSR-4 autoloading:

   {
       "autoload": {
           "psr-4": {
               "XoopsModules\\MyModule\\": "class/"
           }
       }
   }
   

3. Separate concerns:

4. Domain logic in class/
5. Presentation in templates/
6. Controllers in module root

Performance¶

1. Use caching for expensive operations
2. Lazy load resources when possible
3. Minimize database queries using criteria batching
4. Optimize templates by avoiding complex logic

Security¶

1. Validate all input using Xmf\Request
2. Escape output in templates
3. Use prepared statements for database queries
4. Check permissions before sensitive operations

Related Documentation¶

• Design-Patterns - Design patterns used in XOOPS
• Database Layer - Database abstraction details
• Smarty Basics - Template system documentation
• Security Best Practices - Security guidelines

xoops #architecture #core #design #system-design¶