enable/disable plugins by config option

lib/foodsoft_messages/README.md

@@ -11,5 +11,8 @@ add the following to foodsoft's Gemfile:
 gem 'foodsoft_messages', path: 'lib/foodsoft_messages'
 ```
 
+This plugin introduces the foodcoop config option `use_messages`, which can be
+set to `false` to disable messages. May be useful in multicoop deployments.
+
 This plugin is part of the foodsoft package and uses the GPL-3 license (see
 foodsoft's LICENSE for the full license text).

lib/foodsoft_messages/app/controllers/messages_controller.rb

@@ -1,5 +1,7 @@
 class MessagesController < ApplicationController
 
+  before_filter -> { require_plugin_enabled FoodsoftMessages }
+
   # Renders the "inbox" action.
   def index
     @messages = Message.public.page(params[:page]).per(@per_page).order('created_at DESC').includes(:sender)

lib/foodsoft_messages/app/overrides/admin/ordergroups/show/new_message.html.haml.deface

@@ -1,2 +1,3 @@
 / insert_after 'erb:contains("delete")'
-= link_to t('.send_message'), new_message_path(:message => {:group_id => @ordergroup.id}), class: 'btn'
+- if FoodsoftMessages.enabled?
+  = link_to t('.send_message'), new_message_path(:message => {:group_id => @ordergroup.id}), class: 'btn'

lib/foodsoft_messages/app/overrides/admin/users/show/new_message.html.haml.deface

@@ -1,2 +1,3 @@
 / insert_after 'erb:contains("delete")'
-= link_to t('.send_message'), new_message_path(:message => {:mail_to => @user.id}), class: 'btn'
+- if FoodsoftMessages.enabled?
+  = link_to t('.send_message'), new_message_path(:message => {:mail_to => @user.id}), class: 'btn'

lib/foodsoft_messages/app/overrides/admin/workgroups/show/new_message.html.haml.deface

@@ -1,2 +1,3 @@
 / insert_after 'erb:contains("delete")'
-= link_to_new_message(message_params: {group_id: @workgroup.id})
+- if FoodsoftMessages.enabled?
+  = link_to_new_message(message_params: {group_id: @workgroup.id})

lib/foodsoft_messages/app/overrides/foodcoop/ordergroups/_ordergroups/new_message.html.haml.deface

@@ -1,2 +1,3 @@
 / insert_bottom 'tbody tr'
-%td= link_to_new_message(message_params: {group_id: ordergroup.id})
+- if FoodsoftMessages.enabled?
+  %td= link_to_new_message(message_params: {group_id: ordergroup.id})

lib/foodsoft_messages/app/overrides/foodcoop/users/_users/new_message.html.haml.deface

@@ -1,2 +1,3 @@
 / insert_bottom 'tbody tr'
-%td= link_to_new_message(message_params: {mail_to: user.id})
+- if FoodsoftMessages.enabled?
+  %td= link_to_new_message(message_params: {mail_to: user.id})

lib/foodsoft_messages/app/overrides/foodcoop/workgroups/_workgroup/new_message.html.haml.deface

@@ -1,2 +1,3 @@
 / insert_after 'erb:contains("tasks")'
-= link_to_new_message message_params: {group_id: workgroup.id}
+- if FoodsoftMessages.enabled?
+  = link_to_new_message message_params: {group_id: workgroup.id}

lib/foodsoft_messages/app/overrides/home/_start_nav/new_message.html.haml.deface

@@ -1,2 +1,3 @@
 / insert_after 'erb:contains("tasks")'
-%li= link_to t('.write_message'), new_message_path
+- if FoodsoftMessages.enabled?
+  %li= link_to t('.write_message'), new_message_path

lib/foodsoft_messages/app/overrides/home/index/latest_public_messages_index.html.haml.deface

@@ -1,6 +1,7 @@
 / insert_after 'erb[silent]:contains("<dashboard_middle_mark>")'
-- unless Message.public.empty?
-  %section#messages
-    %h2= t '.messages.title'
-    = render 'messages/messages', messages: Message.public.order('created_at DESC').limit(5), pagination: false
-    %p= link_to t('.messages.view_all'), messages_path
+- if FoodsoftMessages.enabled?
+  - unless Message.public.empty?
+    %section#messages
+      %h2= t '.messages.title'
+      = render 'messages/messages', messages: Message.public.order('created_at DESC').limit(5), pagination: false
+      %p= link_to t('.messages.view_all'), messages_path

lib/foodsoft_messages/lib/foodsoft_messages.rb

@@ -3,4 +3,9 @@ require "foodsoft_messages/user_link"
 require "deface"
 
 module FoodsoftMessages
+  # Return whether messages are used or not.
+  # Enabled by default since it used to be part of the foodsoft core.
+  def self.enabled?
+    FoodsoftConfig[:use_messages] != false
+  end
 end

lib/foodsoft_messages/lib/foodsoft_messages/engine.rb

@@ -1,6 +1,7 @@
 module FoodsoftMessages
   class Engine < ::Rails::Engine
     def navigation(primary, context)
+      return unless FoodsoftMessages.enabled?
       return if primary[:foodcoop].nil?
       sub_nav = primary[:foodcoop].sub_navigation
       sub_nav.items <<

lib/foodsoft_messages/lib/foodsoft_messages/user_link.rb

@@ -6,7 +6,7 @@ module FoodsoftMessages
 
         # modify user presentation link to writing a message for the user
         def show_user_link(user=@current_user)
-          if user.nil?
+          if user.nil? or not FoodsoftMessages.enabled?
             show_user user
           else
             link_to show_user(user), new_message_path('message[mail_to]' => user.id),