Ruby on Rails: Extend Engine's Functionality to Entire Application

Question

So I'm using Ruby on Rails for my application, I'm using Thredded for the community aspect and Devise for the authentication aspect.

Although I believe this issue isn't specific to any of the actual Gems and more a general Ruby on Rails question.

To mount the Thredded Gem, I put this code in my route.rb file:

mount Thredded::Engine => '/community/'

This makes the Thredded gem work perfectly from /community/.

I want to use the Thredded navigation across the entire site. However, I can only access things like Thredded.current_user or other specific Thredded variables within the /community/ section of the site.

Is there any way to mount the Thredded::Engine within /community/ but also have aspects of it avaliable outside of that scope?

Here is the Thredded Gem: https://github.com/thredded/thredded

Here is the Thredded navigation:

<nav class="thredded--navigation" role="navigation">
  <ul class="thredded--user-navigation<%= ' thredded--user-navigation-standalone' if Thredded.standalone_layout? %>">
    <% if signed_in? && Thredded.standalone_layout? %>
      <li class="thredded--user-navigation--profile thredded--user-navigation--item">
        <%= link_to thredded_current_user, user_path(thredded_current_user) %>
      </li>
    <% end %>

    <%= render 'thredded/shared/nav/notification_preferences', messageboard: messageboard_or_nil %>
    <%= render 'thredded/shared/nav/private_topics' %>

    <% if Thredded.standalone_layout? %>
      <%= render 'thredded/shared/nav/standalone' %>
    <% end %>
  </ul>
  <div class="thredded--main-navigation">
    <%= yield :thredded_breadcrumbs %>
    <%= render 'thredded/search/form', messageboard: messageboard_or_nil %>
  </div>
</nav>

Here are the shared files the nav is rendering: https://github.com/thredded/thredded/tree/master/app/views/thredded/shared

Here is the Thredded Initializer file:

# frozen_string_literal: true
# Thredded configuration

# ==> User Configuration
# The name of the class your app uses for your users.
# By default the engine will use 'User' but if you have another name
# for your user class - change it here.
Thredded.user_class = 'User'

# User name column, used in @mention syntax and should be unique.
# This is the column used to search for users' names if/when someone is @ mentioned.
Thredded.user_name_column = :name

# The path (or URL) you will use to link to your users' profiles.
# When linking to a user, Thredded will use this lambda to spit out
# the path or url to your user. This lambda is evaluated in the view context.
Thredded.user_path = lambda do |user|
  user_path = :"#{Thredded.user_class.name.underscore}_path"
  main_app.respond_to?(user_path) ? main_app.send(user_path, user) : "#{user.to_param}"
end

# This method is used by Thredded controllers and views to fetch the currently signed-in user
Thredded.current_user_method = :"current_#{Thredded.user_class.name.underscore}"

# User avatar URL. rb-gravatar gem is used by default:
Thredded.avatar_url = ->(user) { user.profile_picture.url }

# ==> Permissions Configuration
# By default, thredded uses a simple permission model, where all the users can post to all message boards,
# and admins and moderators are determined by a flag on the users table.

# The name of the moderator flag column on the users table.
Thredded.moderator_column = :admin
# The name of the admin flag column on the users table.
Thredded.admin_column = :admin

# This model can be customized further by overriding a handful of methods on the User model.
# For more information, see app/models/thredded/user_extender.rb.

# ==> Email Configuration
# Email "From:" field will use the following
# Thredded.email_from = 'no-reply@example.com'

# Incoming email will be directed to this host
# Thredded.email_incoming_host = 'example.com'

# Emails going out will prefix the "Subject:" with the following string
# Thredded.email_outgoing_prefix = '[My Forum] '

# Reply to field for email notifications
# Thredded.email_reply_to = -> postable { "#{postable.hash_id}@#{Thredded.email_incoming_host}" }

# ==> View Configuration
# Set the layout for rendering the thredded views.
Thredded.layout = 'thredded/application'

# ==> Error Handling
# By default Thredded just renders a flash alert on errors such as Topic not found, or Login required.
# Below is an example of overriding the default behavior on LoginRequired:
#
# Rails.application.config.to_prepare do
#   Thredded::ApplicationController.module_eval do
#     rescue_from Thredded::Errors::LoginRequired do |exception|
#       @message = exception.message
#       render template: 'sessions/new', status: :forbidden
#     end
#   end
# end

Thredded Routes:

Routes for Thredded::Engine:
                  theme_preview GET    /theme-preview(.:format)                             thredded/theme_previews#show
              new_private_topic GET    /private-topics/new(.:format)                        thredded/private_topics#new
                  private_topic GET    /private-topics/:id(/page-:page)(.:format)           thredded/private_topics#show {:page=>/[1-9]\d*/}
    private_topic_private_posts POST   /private-topics/:private_topic_id(.:format)          thredded/posts#create
 new_private_topic_private_post GET    /private-topics/:private_topic_id/new(.:format)      thredded/posts#new
edit_private_topic_private_post GET    /private-topics/:private_topic_id/:id/edit(.:format) thredded/posts#edit
     private_topic_private_post PATCH  /private-topics/:private_topic_id/:id(.:format)      thredded/posts#update
                                PUT    /private-topics/:private_topic_id/:id(.:format)      thredded/posts#update
                                DELETE /private-topics/:private_topic_id/:id(.:format)      thredded/posts#destroy
                 private_topics GET    /private-topics(.:format)                            thredded/private_topics#index
                                POST   /private-topics(.:format)                            thredded/private_topics#create
             edit_private_topic GET    /private-topics/:id/edit(.:format)                   thredded/private_topics#edit
                                PATCH  /private-topics/:id(.:format)                        thredded/private_topics#update
                                PUT    /private-topics/:id(.:format)                        thredded/private_topics#update
                                DELETE /private-topics/:id(.:format)                        thredded/private_topics#destroy
             autocomplete_users GET    /autocomplete-users(.:format)                        thredded/autocomplete_users#index
           messageboards_search GET    /                                                    thredded/topics#search
            messageboard_search GET    /:messageboard_id(.:format)                          thredded/topics#search
               edit_preferences GET    /preferences/edit(.:format)                          thredded/preferences#edit
                    preferences PATCH  /preferences(.:format)                               thredded/preferences#update
                                PUT    /preferences(.:format)                               thredded/preferences#update
               new_messageboard GET    /messageboards/new(.:format)                         thredded/messageboards#new
  edit_messageboard_preferences GET    /:messageboard_id/preferences/edit(.:format)         thredded/preferences#edit
       messageboard_preferences PATCH  /:messageboard_id/preferences(.:format)              thredded/preferences#update
                                PUT    /:messageboard_id/preferences(.:format)              thredded/preferences#update
         new_messageboard_topic GET    /:messageboard_id/topics/new(.:format)               thredded/topics#new
            messageboard_topics GET    /:messageboard_id(/page-:page)(.:format)             thredded/topics#index {:page=>/[1-9]\d*/}
 categories_messageboard_topics GET    /:messageboard_id/category/:category_id(.:format)    thredded/topics#category
             messageboard_topic GET    /:messageboard_id/:id(/page-:page)(.:format)         thredded/topics#show {:page=>/[1-9]\d*/}
       messageboard_topic_posts POST   /:messageboard_id/:topic_id(.:format)                thredded/posts#create
    new_messageboard_topic_post GET    /:messageboard_id/:topic_id/new(.:format)            thredded/posts#new
   edit_messageboard_topic_post GET    /:messageboard_id/:topic_id/:id/edit(.:format)       thredded/posts#edit
        messageboard_topic_post PATCH  /:messageboard_id/:topic_id/:id(.:format)            thredded/posts#update
                                PUT    /:messageboard_id/:topic_id/:id(.:format)            thredded/posts#update
                                DELETE /:messageboard_id/:topic_id/:id(.:format)            thredded/posts#destroy
                                POST   /:messageboard_id(.:format)                          thredded/topics#create
        edit_messageboard_topic GET    /:messageboard_id/:id/edit(.:format)                 thredded/topics#edit
                                PATCH  /:messageboard_id/:id(.:format)                      thredded/topics#update
                                PUT    /:messageboard_id/:id(.:format)                      thredded/topics#update
                                DELETE /:messageboard_id/:id(.:format)                      thredded/topics#destroy
                  messageboards GET    /                                                    thredded/messageboards#index
                                POST   /                                                    thredded/messageboards#create
                           root GET    /                                                    thredded/messageboards#index

Answer 1

To reference navigation in your engine from your main app

<%= link_to 'Link text', your_engine_name.path_name_from_the_engines_routes_path, title:"Rails engine" %>

In your example

<%= link_to thredded_current_user, thredded.user_path(thredded_current_user) %>

Use lowercase thredded in all references to the engine from the main app .

If your engine is mounted and configured properly this will work. I only mention this because I don't know what your config is, and rails engines are entirely convention dependent.