Rails 3 dynamic view_path

posted on Tuesday, December 14, 2010

There is an easy way to add view path dynamicly inside ActionController using prepend_view_path or append_view_path. But there is a problem because each request will start a filesystem traversal to do a pathset, we don't want to do that especially if there is a big project.

So here is an idea of how to handle that view_path insertion...

---

application_controller:

class ApplicationController < ActionController::Base
  before_filter :set_custom_view
  protected
    def set_custom_view
      custom_slug = CUSTOM_VIEWS.select {|k,v| request.subdomain.match(Regexp.new(k))}.first
      prepend_view_path(preprocessed_pathsets[ApplicationController.custom_view_path(custom_slug.last)]) if custom_slug
    end
  end

somewhere inside config/initializers:

ActionController::Base.class_eval do

  CUSTOM_VIEWS = {"custom_project"=>"project1", "another_project"=>"project2"}
  
  def self.custom_view_path name
    name=="views" ? "app/views" : "app/views_custom/#{name}"
  end
  
  # preprocess some pathsets on boot
  # doing pathset generation during a request is very costly
  @@preprocessed_pathsets = begin
    CUSTOM_VIEWS.values.inject({}) do |pathsets, slug|
      path = ActionController::Base.custom_view_path(slug)
      pathsets[path] = ActionView::Base.process_view_paths(path).first
      pathsets
    end
  end

  cattr_accessor :preprocessed_pathsets

end

Modified version of unspace's code.

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