Extension System Overview

Learn about ForkBB’s powerful extension system that allows you to customize and extend forum functionality

What are Extensions?

ForkBB features a flexible extension system that allows you to customize and extend your forum without modifying the core codebase. Extensions can add new features, modify existing behavior, hook into events, and integrate with templates.

Extension Directory Structure

Extensions are stored in the ext/ directory at the root of your ForkBB installation:

forkbb/
├── ext/
│   └── vendor-name/
│       └── extension-name/
│           ├── composer.json
│           ├── Actions.php
│           ├── Listeners/
│           │   └── ExampleListener.php
│           └── public/
│               ├── css/
│               └── js/
├── app/
└── public/

How Extensions Work

Extensions are managed through the Extensions model, which:

1. Scans the ext/ directory for composer.json files
2. Validates extension metadata and configuration
3. Manages installation, enabling, disabling, and updates
4. Generates configuration files in app/config/ext/

Extension States

Extensions can be in one of several states:

State	Code	Description
NOT_INSTALLED	0	Extension is present but not installed
DISABLED	4	Extension is installed but disabled
DISABLED_DOWN	5	Extension is disabled and file version is older
DISABLED_UP	6	Extension is disabled and file version is newer
ENABLED	8	Extension is active and running
ENABLED_DOWN	9	Extension is enabled but file version is older
ENABLED_UP	10	Extension is enabled but file version is newer
CRASH	12	Extension files are missing or corrupted

These states are defined in the Extension model:

class Extension extends Model
{
    const NOT_INSTALLED = 0;
    const DISABLED      = 4;
    const DISABLED_DOWN = 5;
    const DISABLED_UP   = 6;
    const ENABLED       = 8;
    const ENABLED_DOWN  = 9;
    const ENABLED_UP    = 10;
    const CRASH         = 12;
}

Configuration Files

When extensions are enabled, ForkBB generates several configuration files in app/config/ext/:

• common.php - Combined data from all extensions
• pre.php - Template pre-processing data
• auto.php - PSR-4 autoloader mappings
• config.php - Extension configuration values
• events.php - Event listener mappings

Extension Capabilities

Extensions can:

• Listen to events to hook into application lifecycle
• Modify templates by injecting content before rendering
• Add routes and controllers for new pages
• Create symlinks to serve static assets from public/
• Register autoloaders for custom PHP classes
• Add configuration values to the forum
• Run installation hooks for setup and teardown

Extension Management

The Extensions manager provides methods to control extension lifecycle:

// Install an extension
$this->c->Extensions->install($extension);

// Enable an extension
$this->c->Extensions->enable($extension);

// Disable an extension
$this->c->Extensions->disable($extension);

// Update an extension
$this->c->Extensions->update($extension);

// Uninstall an extension
$this->c->Extensions->uninstall($extension);

Each method validates the current state and performs the necessary operations to transition the extension to the new state.

Next Steps

Creating Extensions

Learn how to create your own extension

Event System

Understand how to use events in extensions