Table of Contents

Dynamic Plugin Requirements

Author: John Reese

Status: Feedback / Bugfixing


This is a proposal for a very lightweight method of including a plugin/hook system for Mantis. It should be able to handle not only minor enhancements for areas such as outputting text, but adding new pages, menu items, and entire features to the application. It should be very simple, but very powerful.

This feature is meant as a counter point to the Add-Ons Support Requirements by offering a much simpler and easier to use plugin system without sacrificing flexibility or power.

Proposed Approach

Plugins will be very simple packages, extracted into the Mantis/plugins directory and enabled through the Management interface. There will be a simple event system that will handle hooking functionality in various forms, including data processing, list retrieval, and output. Events will be called at various points in the normal flow of Mantis, and the plugin API will handle calling any necessary plugin functions.

When a plugin is loaded at runtime, it will register basic information about itself to Mantis, including its name, author, description, version, and dependencies (Mantis version, other plugins). It will then register a callback function for each event that it would like to handle. When an event occurs, any plugin callbacks will be called in the order they are registered. The event type will determine how callback parameters and return values are processed.

New content pages will be added by creating scripts in a special directory of the plugin, and links to that page will be created with an API call to simplify the task. Plugin pages will not need to load the Mantis core, but will need to call the html_page_top() or html_page_bottom() functions as necessary.

Language Files

To simplify the usage of language files, plugins will simply need to supply a lang/ directory with appropriate strings files. The language API will search for strings in the main language files first, and only load the current plugin's language files if a needed string is not found elsewhere.

Database Schema

There will need to be a simple and unified method for plugins to maintain their database schema, otherwise plugins will get released without proper upgrade paths for users. The plugin manager should provide an automated schema upgrade mechanism that works the same as the Mantis upgrade mechanism. For performance reasons, the schema for plugins should only be checked when the plugin management screens are accessed, where it should notify the user of the need to upgrade the schema.

Event Types

These should be the basic event types, from which all (or most) events can be formed.

Execute event

Output event

Chain event

Default event

Database Changes

Configuration Changes

Sample Event Flows

Plugin Execution

This flow of action should occur during normal Mantis execution. It should be possible to bypass this by either disabling plugins from config_inc.php or by a page declaring a special flag before including core.php.

Event Execution

This flow of action should occur whenever an event is signaled, assuming plugins are enabled.

Plugin Hierarchy

<basename> represents the plugin's directory name, and should be a short, unique name that does not include version names or other changing identifiers. 'mantis' is a reserved basename, and represents a virtual plugin used for allowing dependencies based on Mantis versions.


Sample Plugin (Super Cow Powers)

This is a very minimal plugin.

Directory Structure




 * Return plugin details to the API.
 * @return array Plugin details
function plugin_callback_supercow_info() {
  return array(
    'name' => 'Super Cow Powers',
    'description' => 'Gives your Mantis installation super cow powers.',
    'version' => '1.0',
    'author' => 'John Reese',
    'contact' => '',
    'url' => '',

 * Intitialize the plugin.
function plugin_callback_supercow_init() {
  plugin_event_hook( 'EVENT_PLUGIN_INIT', 'header' );



 * Handle the EVENT_PLUGIN_INIT callback.
function plugin_event_supercow_header() {
  header( 'X-Mantis: This Mantis has super cow powers.' );