Plugin Tutorial

This tutorial is based on Redmine 2.x. You can view a previous version of this tutorial for Redmine 1.x here.
It assumes that you're familiar with the Ruby on Rails framework.

Creating a new Plugin

You may need to set the RAILS_ENV variable in order to use the command below:

$ export RAILS_ENV="production" 

On windows:

$ set RAILS_ENV=production

Creating a new plugin can be done using the Redmine plugin generator.
Syntax for this generator is:

ruby script/rails generate redmine_plugin <plugin_name>

So open up a command prompt and "cd" to your redmine directory, then execute the following command:

$ ruby script/rails generate redmine_plugin Polls
      create  plugins/polls/app
      create  plugins/polls/app/controllers
      create  plugins/polls/app/helpers
      create  plugins/polls/app/models
      create  plugins/polls/app/views
      create  plugins/polls/db/migrate
      create  plugins/polls/lib/tasks
      create  plugins/polls/assets/images
      create  plugins/polls/assets/javascripts
      create  plugins/polls/assets/stylesheets
      create  plugins/polls/config/locales
      create  plugins/polls/test
      create  plugins/polls/README.rdoc
      create  plugins/polls/init.rb
      create  plugins/polls/config/routes.rb
      create  plugins/polls/config/locales/en.yml
      create  plugins/polls/test/test_helper.rb

The plugin structure is created in plugins/polls. Edit plugins/polls/init.rb to adjust plugin information (name, author, description and version):

Redmine::Plugin.register :polls do
  name 'Polls plugin'
  author 'John Smith'
  description 'A plugin for managing polls'
  version '0.0.1'
end

Then restart the application and point your browser to http://localhost:3000/admin/plugins.
After logging in, you should see your new plugin in the plugins list:

Note: any change to the init.rb file of your plugin requires to restart the application as it is not reloaded on each request.

Generating a model

For now plugin doesn't store anything. Let's create a simple Poll model for our plugin. Syntax is:

   ruby script/rails generate redmine_plugin_model <plugin_name> <model_name> [field[:type][:index] field[:type][:index] ...]

So, go to the command prompt and run:

$ ruby script/rails generate redmine_plugin_model polls poll question:string yes:integer no:integer
      create  plugins/polls/app/models/poll.rb
      create  plugins/polls/test/unit/poll_test.rb
      create  plugins/polls/db/migrate/001_create_polls.rb

This creates the Poll model and the corresponding migration file 001_create_polls.rb in plugins/polls/db/migrate:

class CreatePolls < ActiveRecord::Migration
  def change
    create_table :polls do |t|
      t.string :question
      t.integer :yes, :default => 0
      t.integer :no, :default => 0
    end
  end
end

You can adjust your migration file (eg. default values...) then migrate the database using the following command:

$ rake redmine:plugins:migrate

Migrating polls (Polls plugin)...
==  CreatePolls: migrating ====================================================
-- create_table(:polls)
   -> 0.0410s
==  CreatePolls: migrated (0.0420s) ===========================================

Note that each plugin has its own set of migrations.

Lets add some Polls in the console so we have something to work with. The console is where you can interactively work and examine the Redmine environment and is very informative to play around in. But for now we just need create two Poll objects

ruby script/rails console
[rails 3] rails console
>> Poll.create(:question => "Can you see this poll")
>> Poll.create(:question => "And can you see this other poll")
>> exit

Edit plugins/polls/app/models/poll.rb in your plugin directory to add a #vote method that will be invoked from our controller:

class Poll < ActiveRecord::Base
  def vote(answer)
    increment(answer == 'yes' ? :yes : :no)
  end
end

Generating a controller

For now, the plugin doesn't do anything. So let's create a controller for our plugin.
We can use the plugin controller generator for that. Syntax is:

ruby script/rails generate redmine_plugin_controller <plugin_name> <controller_name> [<actions>]

So go back to the command prompt and run:

$ ruby script/rails generate redmine_plugin_controller Polls polls index vote
      create  plugins/polls/app/controllers/polls_controller.rb
      create  plugins/polls/app/helpers/polls_helper.rb
      create  plugins/polls/test/functional/polls_controller_test.rb
      create  plugins/polls/app/views/polls/index.html.erb
      create  plugins/polls/app/views/polls/vote.html.erb

A controller PollsController with 2 actions (#index and #vote) is created.

Edit plugins/polls/app/controllers/polls_controller.rb to implement these 2 actions.

class PollsController < ApplicationController
  unloadable

  def index
    @polls = Poll.all
  end

  def vote
    poll = Poll.find(params[:id])
    poll.vote(params[:answer])
    if poll.save
      flash[:notice] = 'Vote saved.'
    end
    redirect_to :action => 'index'
  end
end

Then edit plugins/polls/app/views/polls/index.html.erb that will display existing polls:

<h2>Polls</h2>

<% @polls.each do |poll| %>
  <p>
  <%= poll.question %>?
  <%= link_to 'Yes', { :action => 'vote', :id => poll[:id], :answer => 'yes' }, :method => :post %> (<%= poll.yes %>) /
  <%= link_to 'No', { :action => 'vote', :id => poll[:id], :answer => 'no' }, :method => :post %> (<%= poll.no %>)
  </p>
<% end %>

You can remove plugins/polls/app/views/polls/vote.html.erb since no rendering is done by the #vote action.

Adding routes

Redmine does not provide the default wildcard route (':controller/:action/:id'). Plugins have to declare the routes they need in their proper config/routes.rb file. So edit plugins/polls/config/routes.rb to add the 2 routes for the 2 actions:

get 'polls', :to => 'polls#index'
post 'post/:id/vote', :to => 'polls#vote'

You can find more information about Rails routes here: http://guides.rubyonrails.org/routing.html.

Now, restart the application and point your browser to http://localhost:3000/polls.
You should see the 2 polls and you should be able to vote for them:

Internationalization

The translation files must be stored in config/locales, eg. plugins/polls/config/locales/.

Extending menus

Our controller works fine but users have to know the url to see the polls. Using the Redmine plugin API, you can extend standard menus.
So let's add a new item to the application menu.

Extending the application menu

Edit plugins/polls/init.rb at the root of your plugin directory to add the following line at the end of the plugin registration block:

Redmine::Plugin.register :redmine_polls do
  [...]

  menu :application_menu, :polls, { :controller => 'polls', :action => 'index' }, :caption => 'Polls'
end

Syntax is:

menu(menu_name, item_name, url, options={})

There are five menus that you can extend:

  • :top_menu - the top left menu
  • :account_menu - the top right menu with sign in/sign out links
  • :application_menu - the main menu displayed when the user is not inside a project
  • :project_menu - the main menu displayed when the user is inside a project
  • :admin_menu - the menu displayed on the Administration page (can only insert after Settings, before Plugins)

Available options are:

  • :param - the parameter key that is used for the project id (default is :id)
  • :if - a Proc that is called before rendering the item, the item is displayed only if it returns true
  • :caption - the menu caption that can be:
    • a localized string Symbol
    • a String
    • a Proc that can take the project as argument
  • :before, :after - specify where the menu item should be inserted (eg. :after => :activity)
  • :first, :last - if set to true, the item will stay at the beginning/end of the menu (eg. :last => true)
  • :html - a hash of html options that are passed to link_to when rendering the menu item

In our example, we've added an item to the application menu which is emtpy by default.
Restart the application and go to http://localhost:3000:

Now you can access the polls by clicking the Polls tab from the welcome screen.

Extending the project menu

Now, let's consider that the polls are defined at project level (even if it's not the case in our example poll model). So we would like to add the Polls tab to the project menu instead.
Open init.rb and replace the line that was added just before with these 2 lines:

Redmine::Plugin.register :redmine_polls do
  [...]

  permission :polls, { :polls => [:index, :vote] }, :public => true
  menu :project_menu, :polls, { :controller => 'polls', :action => 'index' }, :caption => 'Polls', :after => :activity, :param => :project_id
end

The second line adds our Polls tab to the project menu, just after the activity tab. The first line is required and declares that our 2 actions from PollsController are public. We'll come back later to explain this with more details. Restart the application again and go to one of your projects:

If you click the Polls tab (in 3rd position), you should notice that the project menu is no longer displayed.
To make the project menu visible, you have to initialize the controller's instance variable @project.

Edit your PollsController to do so:

def index
  @project = Project.find(params[:project_id])
  @polls = Poll.find(:all) # @project.polls
end

The project id is available in the :project_id param because of the :param => :project_id option in the menu item declaration above.

Now, you should see the project menu when viewing the polls:

Adding new permissions

For now, anyone can vote for polls. Let's make it more configurable by changing the permission declaration.
We're going to declare 2 project based permissions, one for viewing the polls and an other one for voting. These permissions are no longer public (:public => true option is removed).

Edit plugins/polls/init.rb to replace the previous permission declaration with these 2 lines:

  permission :view_polls, :polls => :index
  permission :vote_polls, :polls => :vote

Restart the application and go to http://localhost:3000/roles/permissions:

You're now able to give these permissions to your existing roles.

Of course, some code needs to be added to the PollsController so that actions are actually protected according to the permissions of the current user. For this, we just need to append the :authorize filter and make sure that the @project instance variable is properly set before calling this filter.

Here is how it would look like for the #index action:

class PollsController < ApplicationController
  unloadable

  before_filter :find_project, :authorize, :only => :index

  [...]

  def index
    @polls = Poll.find(:all) # @project.polls
  end

  [...]

  private

  def find_project
    # @project variable must be set before calling the authorize filter
    @project = Project.find(params[:project_id])
  end
end

Retrieving the current project before the #vote action could be done using a similar way.
After this, viewing and voting polls will be only available to admin users or users that have the appropriate role on the project.

If you want to display the symbols of your permissions in a multilangual way, you need to add the necessary text labels in a language file.
Simply create an *.yml (eg. en.yml) file in plugins/polls/config/locales and fill it with labels like this:

"en":
  permission_view_polls: View Polls
  permission_vote_polls: Vote Polls

In this example the created file is known as en.yml, but all other supported language files are also possible too.
As you can see on the example above, the labels consists of the permission symbols :view_polls and :vote_polls with an additional permission_ added at the front.

Restart your application and point the permission section.

Creating a project module

For now, the poll functionality is added to all your projects. But you may want to enable polls for some projects only.
So, let's create a 'Polls' project module. This is done by wrapping the permissions declaration inside a call to #project_module.

Edit init.rb and change the permissions declaration:

  project_module :polls do
    permission :view_polls, :polls => :index
    permission :vote_polls, :polls => :vote
  end

Restart the application and go to one of your project settings.
Click on the Modules tab. You should see the Polls module at the end of the modules list (disabled by default):

You can now enable/disable polls at project level.

Improving the plugin views

Adding stylesheets

Let's start by adding a stylesheet to our plugin views.
Create a file named voting.css in the plugins/polls/assets/stylesheets directory:

a.vote { font-size: 120%; }
a.vote.yes { color: green; }
a.vote.no  { color: red; }

When starting the application, plugin assets are automatically copied to public/plugin_assets/polls/ to make them available through your web server. So any change to your plugin stylesheets or javascripts needs an application restart.

The introduced classes need to be used by the links. So change in file plugins/polls/app/views/polls/index.html.erb the link declarations to:

<%= link_to 'Yes', {:action => 'vote', :id => poll[:id], :answer => 'yes' }, :method => :post, :class => 'vote yes' %> (<%= poll.yes %>)
<%= link_to 'No', {:action => 'vote', :id => poll[:id], :answer => 'no' }, :method => :post, :class => 'vote no' %> (<%= poll.no %>)

Then, append the following lines at the end of index.html.erb so that your stylesheet get included in the page header by Redmine:

<% content_for :header_tags do %>
    <%= stylesheet_link_tag 'voting', :plugin => 'polls' %>
<% end %>

Note that the :plugin => 'polls' option is required when calling the stylesheet_link_tag helper.

Javascripts can be included in plugin views using the javascript_include_tag helper in the same way.

Setting page title

You can set the HTML title from inside your views by using the html_title helper.
Example:

  <% html_title "Polls" %>

Using hooks

Hooks in views

Hooks in Redmine views lets you insert custom content to regular Redmine views. For example, looking at source:tags/2.0.0/app/views/projects/show.html.erb#L52 shows that there are 2 hooks available: one named :view_projects_show_left for adding content to the left part and one named :view_projects_show_right for adding content to the right part of the view.

To use one or more hooks in views, you need to create a class that inherits from Redmine::Hook::ViewListener and implement methods named with the hook(s) you want to use. To append some content to the project overview, add a class to your plugin and require it in your init.rb, then implement methods whose name match the hook names.

For our plugin create a file plugins/polls/lib/polls_hook_listener.rb with this content:

class PollsHookListener < Redmine::Hook::ViewListener
  def view_projects_show_left(context = {})
    return content_tag("p", "Custom content added to the left")
  end

  def view_projects_show_right(context = {})
    return content_tag("p", "Custom content added to the right")
  end
end

Prepend this line to plugins/polls/init.rb:

require_dependency 'polls_hook_listener'

Restart Redmine and have a look into the overview tab of a project. You should see the strings on the left and the right side in the overview.

You can also use the render_on helper to render a partial. In our plugin you have to replace the just created content in plugins/polls/lib/polls_hook_listener.rb with:

class PollsHookListener < Redmine::Hook::ViewListener
  render_on :view_projects_show_left, :partial => "polls/project_overview" 
end

Add the partial to your plugin by creating the file app/views/polls/_project_overview.html.erb. Its content (use some text like 'Message from Hook!') will be appended to the left part of the project overview. Don't forget to restart Redmine.

Hooks in controllers

TODO

Making your plugin configurable

Each plugin registered with Redmine is displayed on the admin/plugins page. Support for a basic configuration mechanism is supplied by the Settings controller. This feature is enabled by adding the "settings" method to the plugin registration block in a plugin's init.rb file.

Redmine::Plugin.register :redmine_polls do
  [ ... ]

  settings :default => {'empty' => true}, :partial => 'settings/poll_settings'
end

Adding this will accomplish two things. First, it will add a "Configure" link to the description block for the plugin in the admin/plugins list. Following this link will cause a common plugin configuration template view to be loaded which will in turn render the partial view referenced by :partial. Calling the settings method will also add support in the Setting module for the plugin. The Setting model will store and retrieve a serialized hash based on the plugin name. This hash is accessed using the Setting method name in the form plugin_<plugin name>. For this example, the hash can be accessed by calling Setting.plugin_redmine_polls.

The view referenced by the :partial hash key passed to the settings method will be loaded as a partial within the plugin configuration view. The basic page layout is constrained by the plugin configuration view: a form is declared and the submit button is generated. The partial is pulled into the view inside a table div inside the form. Configuration settings for the plugin will be displayed and can be modified via standard HTML form elements.

NB : if two plugins have the same partial name for settings, the first will override the second's settings page. So be sure you give a unique name to your settings partial.

When the page is submitted, the settings_controller will take the parameter hash referenced by 'settings' and store it directly in a serialized format in Setting.plugin_redmine_polls. Each time the page is generated the current value of Setting.plugin_redmine_polls will be assigned to the local variable settings.

<table>
  <tbody>
    <tr>
      <th>Notification Default Address</th>
      <td><input type="text" id="settings_notification_default" 
                     value="<%= settings['notification_default'] %>" 
             name="settings[notification_default]" >
    </tr>
  </tbody>
</table>

In the example above, the configuration form was not created using Rails form helpers. This is because there is no @settings model but only the setting hash. Form helpers will attempt to access attributes using model accessor methods which do not exist. For example, a call to @settings.notification_default will fail. The value set by this form is accessed as Setting.plugin_redmine_polls['notification_default'].

Finally, the :default in the settings method call is to register a value that will be returned from the Setting.plugin_redmine_polls call if nothing has been stored in the settings table for this plugin.

Testing your plugin

test/test_helper.rb

Here are the contents of my test helper file:

require File.expand_path(File.dirname(__FILE__) + '/../../../test/test_helper')

Sample test

Contents of polls_controller_test.rb:

require File.expand_path('../../test_helper', __FILE__)

class PollsControllerTest < ActionController::TestCase
  fixtures :projects

  def test_index
    get :index, :project_id => 1

    assert_response :success
    assert_template 'index'
  end
end

Running test

Initialize the test database if necessary:

$ rake db:drop db:create db:migrate redmine:plugins:migrate redmine:load_default_data RAILS_ENV=test

To execute the polls_controller_test.rb:

$ ruby plugins\polls\test\functionals\polls_controller_test.rb

Testing with permissions

If your plugin requires membership to a project, add the following to the beginning of your functional tests:

def test_index
  @request.session[:user_id] = 2
  ...
end

If your plugin requires a specific permission, you can add that to a user role like so (lookup which role is appropriate for the user in the fixtures):

def test_index
  Role.find(1).add_permission! :my_permission
  ...
end

You may enable/disable a specific module like so:

def test_index
  Project.find(1).enabled_module_names = [:mymodule]
  ...
end

plugins_list1.png (3.23 KB) Jean-Philippe Lang, 2008-08-08 20:33

pools1.png (16.5 KB) Jean-Philippe Lang, 2008-08-10 17:37

application_menu.png (9.22 KB) Jean-Philippe Lang, 2008-08-10 18:08

project_menu.png (7.26 KB) Jean-Philippe Lang, 2008-08-10 18:26

project_menu_pools.png (7.38 KB) Jean-Philippe Lang, 2008-08-10 18:38

permissions1.png (8.43 KB) Jean-Philippe Lang, 2008-08-10 19:10

modules.png (10 KB) Jean-Philippe Lang, 2008-08-10 19:36

project_menu.png (17.3 KB) Ric Turley, 2010-05-15 15:53

project_menu_pools.png (16.9 KB) Ric Turley, 2010-05-15 15:53

plugins_list1.png (4.37 KB) Jean-Philippe Lang, 2012-05-28 10:51

plugin_config_view.png (21.6 KB) Paul Kerr, 2013-02-01 19:13

plugin_with_config.png (24.3 KB) Paul Kerr, 2013-02-01 19:14