Introduction to Modules

You can extend the functionality of Omeka S by writing an add-on component called a module. Zend Framework provides a substantial framework for writing modules, but Omeka S provides extra structure that makes the modules installable, upgradeable, and integratable.

Directory Structure

At its most basic level, a module directory is structured like so:

MyModule/
    Module.php
    config/
        module.ini
        module.config.php
    src/
        <library-directories-and-files>
    asset/
        <asset-directories-and files>/
    view/
        <module-namespace>/
            <controller-directories>/
                <action-template-files>.phtml
        common/
          mymodule-<template-files>.phtml

The name of the module directory (MyModule above) is significant. It must be a reasonably unique, concise, and descriptive name of your module in CamelCase format.

The asset directory contains assets such as JavaScript, CSS, and image files, usually in their own subdirectories.

When using a shared directory in the view directory (such as common above) be sure to name the templates in such a way to avoid naming collisions. A good practice is to prefix the template names with the name of your plugin.

config/module.ini

Every module must have an INI file, a file containing basic information about the module. The file must be named module.ini and be saved in your module's config/ directory. This file must start with [info] on the first line.

Required information

• name: The human-readable name of the module
• version: The current version of the module

Optional information

• author: The author of the module
• configurable: Whether the module is configurable, true or false
• description: A description of the module
• module_link: An absolute URL to a page about the module
• author_link: An absolute URL to a page about the author
• omeka_version_constraint: A Composer version constraint for what versions of the Omeka S core this module works with

For example:

[info]
name         = "My Module"
version      = "1.0"
author       = "My Organization"
configurable = true
description  = "Lorem ipsum dolor sit amet, consectetur adipiscing elit."
module_link  = "http://my-organization.com/my-module"
author_link  = "http://my-organization.com"
omeka_version_constraint = "^1.0.0"

Module.php

The Module.php file (and the Module class) is required. It provides the methods needed to integrate your custom functionality with Omeka S.

Module configuration

Note that your module's configuration must be returned from your module's getConfig() method. Even so, we recommend that you include a config/module.config.php file to better organize your code.

use Omeka\Module\AbstractModule;
use Zend\View\Model\ViewModel;
use Zend\Mvc\Controller\AbstractController;

class Module extends AbstractModule
{
    /** Module body **/

    /**
     * Get this module's configuration array.
     *
     * @return array
     */
    public function getConfig()
    {
        return include __DIR__ . '/config/module.config.php';
    }
}

This config file is where you take care of many required tasks, such as registering controllers, entities, routes, and navigation. It is a keyed array that should be returned. Here is an excerpt from the MetadataBrowse module as an example:

return [
    'view_manager' => [
        'template_path_stack' => [
            OMEKA_PATH.'/modules/MetadataBrowse/view',
        ],
    ],
    'controllers' => [
        'invokables' => [
            'MetadataBrowse\Controller\Admin\Index' => 'MetadataBrowse\Controller\Admin\IndexController',
        ],
    ],
    'form_elements' => [
        'factories' => [
            'MetadataBrowse\Form\ConfigForm' => 'MetadataBrowse\Service\Form\ConfigFormFactory',
        ],
    ],
];

User configuration

To enable your module's user configuration, remember to set configurable = true in config/module.ini and use the getConfigForm() and handleConfigForm() methods in your module class, like below:

use Omeka\Module\AbstractModule;
use Zend\View\Model\ViewModel;
use Zend\Mvc\Controller\AbstractController;

class Module extends AbstractModule
{
    /** Module body **/

    /**
     * Get this module's configuration form.
     *
     * @param ViewModel $view
     * @return string
     */
    public function getConfigForm(ViewModel $view)
    {
        return '<input name="foo">';
    }

    /**
     * Handle this module's configuration form.
     *
     * @param AbstractController $controller
     * @return bool False if there was an error during handling
     */
    public function handleConfigForm(AbstractController $controller)
    {
        return true;
    }
}

Attaching to Omeka Events

Extending functionality is largely a matter of attaching listeners to events that Omeka triggers at critical times. Modules can attach to Omeka S's server-side events in the Module.php file. Use the attachListeners method in your module class, like below:

use Omeka\Module\AbstractModule;
use Zend\EventManager\Event;
use Zend\EventManager\SharedEventManagerInterface;

class Module extends AbstractModule
{
    /** Module body **/

    /**
     * Attach listeners to events.
     *
     * @param SharedEventManagerInterface $sharedEventManager
     */
    public function attachListeners(SharedEventManagerInterface $sharedEventManager)
    {
        $sharedEventManager->attach(
            'Omeka\Controller\Admin\Item', // identifier for event emitting component
            'view.show.after', // event name
            function (Event $event) { // any callback
                // do something during the `view.show.after` event for a `Omeka\Controller\Admin\Item`
            }
        );
    }
}

MVC

Omeka S uses Zend Framework's MVC layer to coordinate between its data, program logic, and presentation components. For an introduction and detailed reference to the MVC layer, please read Zend Framework's documentation. The Quick Start guide is particularly helpful because it demonstrates how to do the following:

• Set up your view manager and controller configurations
• Create your controllers
• Create your view scripts
• Bring it all together by creating your routes

You can follow those directions as well as the directions we provide in this section to create your own Omeka S module.

Packaging a Module

• At minimum, a module MUST contain a Module.php file and a config/module.ini file, following the requirements described above.
• It SHOULD be made available as a .zip file

Adding to omeka.org

See Register an addon.