How can I globally override a rails url helper?

Question

I needed to add a simple change to foo_path, so I did this:

module ApplicationHelper
  # [...]

  def foo_path(foo, options = {})
    options.merge!(bar: foo.some_attribute)
    super
  end

  # [...]
end

Now, this works when called from a view, but when called from a controller, the original variant without my additions is used.

How can I override the according helpers (_path/_url) application wide?

Answer 1

I think the cleanest way to achieve that is to customize routes.rb file (at least for static default parameters). Docs: http://guides.rubyonrails.org/routing.html#customizing-resourceful-routes

Default param example:

get "/foo(/:bar)" => "my_controller#index", defaults: { bar: "my_default" }

Default param value example + scope:

scope '/(:rec_type)', defaults: { rec_type: 'mammo' }, rec_type: /mammo|face/ do
  resources :patients
end

Other options (for dynamic restriccions):

Advanced routing constraints:

If you need more advanced/dynamic restrictions, take a look to this guide: http://guides.rubyonrails.org/routing.html#advanced-constraints.

Override default_url_options:

Also, you can override default_url_options method to automatically add some attributes (params) using routes helpers: http://guides.rubyonrails.org/action_controller_overview.html#default-url-options.

You can set global default parameters for URL generation by defining a method called default_url_options in your controller. Such a method must return a hash with the desired defaults, whose keys must be symbols:

class ApplicationController < ActionController::Base
  def default_url_options(options = {})
    if action_name == 'foo' # or other conditions
      options[:bar] = 'your_defaults' # add here your default attributes
    end

    options
  end
end

Override to_param:

Rails routing system calls to_param on models to get a value for the :id placeholder. ActiveRecord::Base#to_param returns the id of a model, but you can redefine that method in your models. For example, given:

class Product < ActiveRecord::Base
  def to_param
    "#{id}-#{title}"
  end
end

This would generate: /products/254-Foo

Answer 2

In Rails 3 and 4, route url helpers all resides in this module Rails.application.routes.url_helpers. So we can include a module to override methods inside it.

module FooUrlHelper
  def foo_path(foo, options = {})
    options.merge!(bar: foo.some_attribute)
    super
  end
end

# Works at Rails 4.2.1
Rails.application.routes.url_helpers.send(:include, FooUrlHelper)

# For Rails 4.2.6, I thought the following worked, but there seems to be issues, don't have time to figure out a solution yet
Rails.application.routes.named_routes.url_helpers_module.send(:include, FooUrlHelper)

You can just place this inside initializers

I tried this in console and controller and seems to work fine.

Answer 3

Looks like you are facing wrong way. You would better add :bar param in your route, like:

get :foo, :bar => "bar"

Otherwise, please provide more descriptive details about your problem.

Edit.

Here is the solution(basic on your post update):

class ApplicationController < ActionController::Base
  def foo_path(foo, options = {})
    options.merge!(bar: foo.some_attribute)
    super
  end  
  helper_method :foo_path
end