How to use url helpers in lib modules, and set host for multiple environments

Question

In a Rails 3.2 app I need to access url_helpers in a lib file. I\'m using

Rails.application.routes.url_helpers.model_url(model)

<

Answer 1

This is a problem that I keep running into and has bugged me for a while.

I know many will say it goes against the MVC architecture to access url_helpers in models and modules, but there are times—such as when interfacing with an external API—where it does make sense.

And now thanks to this great blog post I've found an answer!

#lib/routing.rb

module Routing
  extend ActiveSupport::Concern
  include Rails.application.routes.url_helpers

  included do
    def default_url_options
      ActionMailer::Base.default_url_options
    end
  end
end

#lib/url_generator.rb

class UrlGenerator
  include Routing
end

I can now call the following in any model, module, class, console, etc

UrlGenerator.new.models_url

Result!

Answer 2

A slight improvement (at least for me) on Andy's lovely answer

module UrlHelpers

  extend ActiveSupport::Concern

  class Base
    include Rails.application.routes.url_helpers

    def default_url_options
      ActionMailer::Base.default_url_options
    end
  end

  def url_helpers
    @url_helpers ||= UrlHelpers::Base.new
  end

  def self.method_missing method, *args, &block
    @url_helpers ||= UrlHelpers::Base.new

    if @url_helpers.respond_to?(method)
      @url_helpers.send(method, *args, &block)
    else
      super method, *args, &block
    end
  end

end

and the way you use it is:

include UrlHelpers
url_helpers.posts_url # returns https://blabla.com/posts

or simply

UrlHelpers.posts_url # returns https://blabla.com/posts

Thank you Andy! +1

Answer 3

Use this string in any module controller to get application URL-helpers works in any view or controller.

include Rails.application.routes.url_helpers

Please note, some internal module url-helpers should be namespaced.

Example: root application

routes.rb

Rails.application.routes.draw do
get 'action' =>  "contr#action", :as => 'welcome'
mount Eb::Core::Engine => "/" , :as => 'eb'
end

Url helpers in module Eb:

users_path

Add include Rails.application.routes.url_helpers in controller contr

So after that helper should be

eb.users_path

So inside Eb module you can use welcome_path same as in root application!

Answer 4

Not sure if this works in Rails 3.2, but in later versions setting default url options for the routes can be done directly on the routes instance.

So for example, to set the same options as for ActionMailer:

Rails.application.routes.default_url_options = ActionMailer::Base.default_url_options