Developing Custom Plugins

This comprehensive guide walks you through creating custom plugins for ITSM-NG, from basic structure to advanced integration.

Getting Started

Prerequisites

Before developing a plugin, you should have:

Understanding of PHP and object-oriented programming
Familiarity with ITSM-NG architecture and database structure
Knowledge of HTML, CSS, and JavaScript for UI components
A development environment with ITSM-NG installed
Access to ITSM-NG source code for reference

Development Environment Setup

Create Plugin Directory

cd /var/www/html/itsm-ng/plugins/
mkdir myplugin
cd myplugin

Set Development Permissions

chown -R $USER:www-data /var/www/html/itsm-ng/plugins/myplugin
chmod -R 775 /var/www/html/itsm-ng/plugins/myplugin

Enable Error Reporting

In your ITSM-NG config, enable debugging during development to catch errors early.

Basic Plugin Structure

Create the following directory structure:

plugins/myplugin/
├── setup.php              # Required: Plugin metadata and initialization
├── hook.php               # Optional: Hook implementations
├── README.md              # Documentation
├── LICENSE                # License file (GPLv2+ recommended)
├── locales/              # Internationalization
│   ├── en_GB.mo
│   ├── en_GB.po
│   ├── fr_FR.mo
│   └── fr_FR.po
├── inc/                  # PHP classes
│   ├── config.class.php
│   ├── item.class.php
│   └── profile.class.php
├── front/                # User interface pages
│   ├── config.php
│   ├── item.php
│   └── item.form.php
├── ajax/                 # AJAX handlers
│   └── handler.php
├── css/                  # Stylesheets
│   └── styles.css
├── js/                   # JavaScript files
│   └── scripts.js
├── pics/                 # Images and icons
│   └── icon.png
└── sql/                  # Database scripts
    ├── install.sql
    └── uninstall.sql

Creating setup.php

The setup.php file is required and contains plugin metadata and initialization:

<?php

/**
 * Plugin version information
 */
function plugin_version_myplugin() {
    return [
        'name'           => 'My Plugin',
        'version'        => '1.0.0',
        'author'         => 'Your Name',
        'license'        => 'GPLv2+',
        'homepage'       => 'https://github.com/yourusername/myplugin',
        'requirements'   => [
            'glpi' => [
                'min' => '10.0.0',
                'max' => '11.0.0'
            ],
            'php' => [
                'min' => '7.4.0',
                'exts' => [
                    'curl',
                    'json',
                    'mysqli'
                ]
            ]
        ]
    ];
}

/**
 * Check plugin prerequisites
 */
function plugin_myplugin_check_prerequisites() {
    // Check GLPI version
    if (version_compare(GLPI_VERSION, '10.0.0', 'lt')) {
        echo "This plugin requires GLPI >= 10.0.0";
        return false;
    }
    
    // Check required extensions
    if (!extension_loaded('curl')) {
        echo "This plugin requires PHP curl extension";
        return false;
    }
    
    return true;
}

/**
 * Check plugin configuration
 */
function plugin_myplugin_check_config() {
    // Return true if plugin is configured
    // Return false if configuration is required
    return true;
}

/**
 * Initialize plugin
 */
function plugin_init_myplugin() {
    global $PLUGIN_HOOKS;
    
    // Register plugin
    $PLUGIN_HOOKS['csrf_compliant']['myplugin'] = true;
    
    // Initialize plugin classes
    Plugin::registerClass('PluginMypluginItem', [
        'document_types'     => true,
        'ticket_types'       => true,
        'addtabon'          => ['Computer', 'Ticket']
    ]);
    
    // Add menu entry
    $PLUGIN_HOOKS['menu_toadd']['myplugin'] = ['tools' => 'PluginMypluginMenu'];
    
    // Add to config menu
    $PLUGIN_HOOKS['config_page']['myplugin'] = 'front/config.php';
    
    // Add CSS and JS
    $PLUGIN_HOOKS['add_css']['myplugin'] = 'css/styles.css';
    $PLUGIN_HOOKS['add_javascript']['myplugin'] = 'js/scripts.js';
}

Source: inc/plugin.class.php:1521-1538

Installation and Uninstallation

Install Function

Create database tables and initialize plugin data:

/**
 * Install plugin
 */
function plugin_myplugin_install() {
    global $DB;
    
    // Check if already installed
    if (TableExists('glpi_plugin_myplugin_items')) {
        return true;
    }
    
    // Create database tables
    $query = "CREATE TABLE IF NOT EXISTS `glpi_plugin_myplugin_items` (
        `id` int(11) NOT NULL AUTO_INCREMENT,
        `name` varchar(255) NOT NULL,
        `entities_id` int(11) NOT NULL DEFAULT '0',
        `is_recursive` tinyint(1) NOT NULL DEFAULT '0',
        `date_creation` timestamp NULL DEFAULT NULL,
        `date_mod` timestamp NULL DEFAULT NULL,
        PRIMARY KEY (`id`),
        KEY `name` (`name`),
        KEY `entities_id` (`entities_id`),
        KEY `is_recursive` (`is_recursive`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci";
    
    $DB->queryOrDie($query, $DB->error());
    
    // Create config table
    $query = "CREATE TABLE IF NOT EXISTS `glpi_plugin_myplugin_configs` (
        `id` int(11) NOT NULL AUTO_INCREMENT,
        `api_key` varchar(255) DEFAULT NULL,
        `api_url` varchar(255) DEFAULT NULL,
        PRIMARY KEY (`id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci";
    
    $DB->queryOrDie($query, $DB->error());
    
    // Insert default configuration
    $query = "INSERT INTO `glpi_plugin_myplugin_configs` 
              (`id`, `api_key`, `api_url`) 
              VALUES (1, '', '')";
    
    $DB->queryOrDie($query, $DB->error());
    
    return true;
}

Source: inc/plugin.class.php:724-784

Uninstall Function

Remove all plugin data:

/**
 * Uninstall plugin
 */
function plugin_myplugin_uninstall() {
    global $DB;
    
    // Drop all plugin tables
    $tables = [
        'glpi_plugin_myplugin_items',
        'glpi_plugin_myplugin_configs'
    ];
    
    foreach ($tables as $table) {
        $query = "DROP TABLE IF EXISTS `$table`";
        $DB->queryOrDie($query, $DB->error());
    }
    
    // Remove plugin-specific rights from profiles
    $query = "DELETE FROM `glpi_profilerights` 
              WHERE `name` LIKE 'plugin_myplugin_%'";
    $DB->queryOrDie($query, $DB->error());
    
    // Clean up cron tasks
    CronTask::Unregister('myplugin');
    
    return true;
}

Source: inc/plugin.class.php:670-711

Creating Plugin Classes

Basic Item Class

Create inc/item.class.php:

<?php

class PluginMypluginItem extends CommonDBTM {
    
    // Right management
    static $rightname = 'plugin_myplugin_item';
    
    /**
     * Get type name
     */
    static function getTypeName($nb = 0) {
        return __('My Plugin Item', 'myplugin');
    }
    
    /**
     * Get menu name
     */
    static function getMenuName() {
        return static::getTypeName(Session::getPluralNumber());
    }
    
    /**
     * Show form
     */
    function showForm($ID, $options = []) {
        if (!$this->canView()) {
            return false;
        }
        
        if ($ID > 0) {
            $this->check($ID, READ);
        } else {
            $this->check(-1, CREATE);
        }
        
        $this->showFormHeader($options);
        
        echo "<tr class='tab_bg_1'>";
        echo "<td>" . __('Name') . "</td>";
        echo "<td>";
        Html::autocompletionTextField($this, 'name');
        echo "</td>";
        echo "</tr>";
        
        $this->showFormButtons($options);
        
        return true;
    }
    
    /**
     * Get search options
     */
    function rawSearchOptions() {
        $tab = [];
        
        $tab[] = [
            'id'   => 'common',
            'name' => self::getTypeName()
        ];
        
        $tab[] = [
            'id'            => '1',
            'table'         => $this->getTable(),
            'field'         => 'name',
            'name'          => __('Name'),
            'datatype'      => 'itemlink',
            'massiveaction' => false
        ];
        
        $tab[] = [
            'id'            => '2',
            'table'         => $this->getTable(),
            'field'         => 'id',
            'name'          => __('ID'),
            'massiveaction' => false,
            'datatype'      => 'number'
        ];
        
        return $tab;
    }
}

Source: inc/plugin.class.php:1307-1372

Configuration Class

Create inc/config.class.php:

<?php

class PluginMypluginConfig extends CommonDBTM {
    
    static $rightname = 'config';
    
    /**
     * Get configuration
     */
    static function getConfig() {
        global $DB;
        
        $config = new self();
        $config->getFromDB(1);
        
        return $config->fields;
    }
    
    /**
     * Update configuration
     */
    static function setConfig($data) {
        $config = new self();
        return $config->update(array_merge(['id' => 1], $data));
    }
    
    /**
     * Show configuration form
     */
    function showConfigForm() {
        if (!Config::canUpdate()) {
            return false;
        }
        
        $config = self::getConfig();
        
        echo "<form method='post' action='" . $this->getFormURL() . "'>";
        echo "<div class='center' id='tabsbody'>";
        echo "<table class='tab_cadre_fixe'>";
        
        echo "<tr><th colspan='2'>" . __('Plugin Configuration', 'myplugin') . "</th></tr>";
        
        echo "<tr class='tab_bg_1'>";
        echo "<td>" . __('API Key', 'myplugin') . "</td>";
        echo "<td>";
        echo "<input type='text' name='api_key' value='" . $config['api_key'] . "' size='50'>";
        echo "</td>";
        echo "</tr>";
        
        echo "<tr class='tab_bg_1'>";
        echo "<td>" . __('API URL', 'myplugin') . "</td>";
        echo "<td>";
        echo "<input type='text' name='api_url' value='" . $config['api_url'] . "' size='50'>";
        echo "</td>";
        echo "</tr>";
        
        echo "<tr class='tab_bg_2'>";
        echo "<td class='center' colspan='2'>";
        echo "<input type='submit' name='update' value='" . __('Save') . "' class='submit'>";
        echo "</td>";
        echo "</tr>";
        
        echo "</table></div>";
        Html::closeForm();
        
        return true;
    }
}

Implementing Hooks

Create hook.php to handle various ITSM-NG hooks:

<?php

/**
 * Display hook on item form
 */
function plugin_myplugin_item_add_form(CommonDBTM $item) {
    if ($item instanceof Computer) {
        echo "<tr class='tab_bg_1'>";
        echo "<th>" . __('My Plugin Info', 'myplugin') . "</th>";
        echo "<td>Custom content for computers</td>";
        echo "</tr>";
    }
}

/**
 * Hook called when item is added
 */
function plugin_myplugin_item_add(CommonDBTM $item) {
    if ($item instanceof Computer) {
        // Perform action when computer is created
        error_log("Computer created: " . $item->fields['name']);
    }
}

/**
 * Hook called when item is updated
 */
function plugin_myplugin_item_update(CommonDBTM $item) {
    if ($item instanceof Computer) {
        // Perform action when computer is updated
        error_log("Computer updated: " . $item->fields['name']);
    }
}

/**
 * Hook called when item is deleted
 */
function plugin_myplugin_item_purge(CommonDBTM $item) {
    if ($item instanceof Computer) {
        // Perform cleanup when computer is deleted
        error_log("Computer deleted: " . $item->fields['name']);
    }
}

/**
 * Add custom search options
 */
function plugin_myplugin_getAddSearchOptionsNew($itemtype) {
    $options = [];
    
    if ($itemtype == 'Computer') {
        $options[] = [
            'id'       => '9000',
            'table'    => 'glpi_plugin_myplugin_items',
            'field'    => 'custom_field',
            'name'     => __('Custom Field', 'myplugin'),
            'datatype' => 'text'
        ];
    }
    
    return $options;
}

/**
 * Register database relations
 */
function plugin_myplugin_getDatabaseRelations() {
    return [
        'glpi_computers' => [
            'glpi_plugin_myplugin_items' => 'computers_id'
        ],
        'glpi_entities' => [
            'glpi_plugin_myplugin_items' => 'entities_id'
        ]
    ];
}

/**
 * Register dropdowns
 */
function plugin_myplugin_getDropdown() {
    return [
        'PluginMypluginCategory' => __('My Plugin Category', 'myplugin'),
        'PluginMypluginType'     => __('My Plugin Type', 'myplugin')
    ];
}

Source: inc/plugin.class.php:1383-1427, 1650-1680, 1583-1595 Register your plugin in the menu system:

function plugin_init_myplugin() {
    global $PLUGIN_HOOKS;
    
    // Add to Tools menu
    $PLUGIN_HOOKS['menu_toadd']['myplugin'] = [
        'tools' => 'PluginMypluginMenu'
    ];
    
    // Add to Config menu  
    $PLUGIN_HOOKS['menu_toadd']['myplugin'] = [
        'config' => 'PluginMypluginMenu'
    ];
}

class PluginMypluginMenu extends CommonGLPI {
    
    static function getMenuName() {
        return __('My Plugin', 'myplugin');
    }
    
    static function getMenuContent() {
        $menu = [];
        
        $menu['title'] = self::getMenuName();
        $menu['page']  = '/plugins/myplugin/front/item.php';
        $menu['icon']  = 'fas fa-puzzle-piece';
        
        $menu['options']['item'] = [
            'title' => PluginMypluginItem::getTypeName(2),
            'page'  => '/plugins/myplugin/front/item.php',
            'icon'  => 'fas fa-list'
        ];
        
        $menu['options']['config'] = [
            'title' => __('Configuration'),
            'page'  => '/plugins/myplugin/front/config.php',
            'icon'  => 'fas fa-cog'
        ];
        
        return $menu;
    }
}

Internationalization

Create translation files in the locales/ directory:

Creating .pot Template

cd /var/www/html/itsm-ng/plugins/myplugin
xgettext -o locales/myplugin.pot --language=PHP \
  --keyword=__ --keyword=_n:1,2 --keyword=_x:1c,2 \
  --from-code=UTF-8 *.php inc/*.php front/*.php

Creating Language Files

Copy myplugin.pot to locales/en_GB.po
Translate strings in the .po file
Compile to .mo format:

msgfmt locales/en_GB.po -o locales/en_GB.mo

Using Translations

// Simple translation
echo __('Hello World', 'myplugin');

// Plural forms
echo _n('One item', '%d items', $count, 'myplugin');

// Context-specific translation
echo _x('button', 'Save', 'myplugin');

Source: inc/plugin.class.php:288-378

Best Practices

Naming Conventions

Plugin directory: Lowercase, no spaces (e.g., myplugin)
Classes: PluginMypluginClassname (CamelCase with plugin prefix)
Functions: plugin_myplugin_function_name (lowercase with underscores)
Database tables: glpi_plugin_myplugin_tablename (lowercase with underscores)
Rights: plugin_myplugin_right (lowercase with underscores)

Security

// Always sanitize user input
$name = $DB->escape($_POST['name']);

// Use prepared statements
$query = "SELECT * FROM glpi_plugin_myplugin_items WHERE id = ?";
$result = $DB->query($query, [$id]);

// Check permissions
if (!$item->canView()) {
    Html::displayRightError();
    return;
}

// CSRF protection (automatically enabled)
$PLUGIN_HOOKS['csrf_compliant']['myplugin'] = true;

Source: inc/plugin.class.php:803-813

Performance

Lazy loading: Only load classes when needed
Caching: Use ITSM-NG’s cache system for expensive operations
Database indexing: Add indexes to frequently queried columns
Minimize hooks: Only implement hooks you actually need

Error Handling

try {
    $result = $DB->query($query);
    if (!$result) {
        throw new Exception('Database query failed');
    }
} catch (Exception $e) {
    Toolbox::logError($e->getMessage());
    Session::addMessageAfterRedirect(
        __('An error occurred', 'myplugin'),
        false,
        ERROR
    );
}

Testing Your Plugin

Install in Development

Install the plugin in your development ITSM-NG instance.

Test Installation Process

Verify database tables are created correctly and default data is inserted.

Test Activation

Ensure the plugin activates without errors and appears in menus.

Test Functionality

Verify all features work as expected, including forms, searches, and hooks.

Test Deactivation

Confirm the plugin deactivates cleanly without breaking ITSM-NG.

Test Uninstallation

Verify all data is removed and no orphaned records remain.

Test Updates

Test upgrading from one version to another with database migrations.

Debugging

Enable debugging during development:

// In your plugin code
error_log("Debug info: " . print_r($data, true));

// Use GLPI's debugging
Toolbox::logDebug("Debug message");
Toolbox::logError("Error message");
Toolbox::logWarning("Warning message");

// Check SQL queries
$DB->query($query) or die($DB->error());

Distribution

Preparing for Release

Update version in setup.php
Create changelog documenting changes
Update README with installation instructions
Test thoroughly in a clean ITSM-NG installation
Check compatibility with target ITSM-NG versions

Packaging

# Create release archive
cd /var/www/html/itsm-ng/plugins/
tar -czf myplugin-1.0.0.tar.gz myplugin/ \
  --exclude='myplugin/.git' \
  --exclude='myplugin/node_modules' \
  --exclude='myplugin/*.log'

Publishing

Create a GitHub repository
Tag releases with version numbers
Submit to GLPI/ITSM-NG plugin directory
Provide documentation and support channels

Next Steps

Plugin System Overview - Understand the architecture
Installing Plugins - Learn plugin installation
ITSM-NG Developer Documentation - Advanced topics and API reference

Get Started

Core Concepts

User Guide

Administration

Plugins & Extensions

Developing Custom Plugins

Getting Started

Prerequisites

Development Environment Setup

Basic Plugin Structure

Creating setup.php

Installation and Uninstallation

Install Function

Uninstall Function

Creating Plugin Classes

Basic Item Class

Configuration Class

Implementing Hooks

Adding Menu Entries

Internationalization

Creating .pot Template

Creating Language Files

Using Translations

Best Practices

Naming Conventions

Security

Performance

Error Handling

Testing Your Plugin

Debugging

Distribution

Preparing for Release

Packaging

Publishing

Next Steps

Build docs developers (and LLMs) love

Get Started

Core Concepts

User Guide

Administration

Plugins & Extensions

​Getting Started

​Prerequisites

​Development Environment Setup

​Basic Plugin Structure

​Creating setup.php

​Installation and Uninstallation

​Install Function

​Uninstall Function

​Creating Plugin Classes

​Basic Item Class

​Configuration Class

​Implementing Hooks

​Adding Menu Entries

​Internationalization

​Creating .pot Template

​Creating Language Files

​Using Translations

​Best Practices

​Naming Conventions

​Security

​Performance

​Error Handling

​Testing Your Plugin

​Debugging

​Distribution

​Preparing for Release

​Packaging

​Publishing

​Next Steps

Build docs developers (and LLMs) love

Getting Started

Prerequisites

Development Environment Setup

Basic Plugin Structure

Creating setup.php

Installation and Uninstallation

Install Function

Uninstall Function

Creating Plugin Classes

Basic Item Class

Configuration Class

Implementing Hooks

Adding Menu Entries

Internationalization

Creating .pot Template

Creating Language Files

Using Translations

Best Practices

Naming Conventions

Security

Performance

Error Handling

Testing Your Plugin

Debugging

Distribution

Preparing for Release

Packaging

Publishing

Next Steps