As of Rails 2.3, what's the right way to add a directory to the load path so that it hooks into Rails' auto-reloading mechanisms?
The specific example I'm thinking of is I have a class that has several sub-classes using STI and I thought it would be a good idea to put them in a sub-directory rather than clutter the top-level. So I would have something like:
#app/models/widget.rb
class Widget < ActiveRecord::Base
add_to_load_path File.join(File.dirname(__FILE__), "widgets")
end
#app/models/widgets/bar_widget.rb
class BarWidget < Widget
end
#app/models/widgets/foo_widget.rb
class FooWidget < Widget
end
It's the add_to_load_path method that I'm looking for.
In the current version of Rails (3.2.8), this has been changed in the application.rb file.
The code is currently commented out as:
# Custom directories with classes and modules you want to be autoloadable.
# config.autoload_paths += %W(#{config.root}/extras)
Will need to update the autoload_paths value. Attempting to modify the the former load_paths variable causes this error.
/configuration.rb:85:in `method_missing': undefined method `load_paths' for #<Rails::Application::Configuration:0xac670b4> (NoMethodError)
for an example, for each path to add to autoload_paths config, add a line similar to the following:
config.autoload_paths += %W(#{config.root}/app/validators)
config.autoload_paths accepts an array of paths from which Rails will autoload constants. Default is all directories under app.
http://guides.rubyonrails.org/configuring.html
From commentor (hakunin) below:
If the directory is under app/, you don't need to add it anywhere, it should just work by default (definitely in 3.2.12). Rails has eager_load_paths that acts as autoload_paths in development, and eager load in production. All app/* directories are automatically added there.
For older versions of Rails:
You can do this in your environment.rb config file.
config.load_paths << "#{RAILS_ROOT}/app/widgets"
--
For Rails 3, see answers bellow
In Rails 5 you don't have to explicitly load folders from within the app directory anymore. All folders placed inside are directly available. You don't have to touch any of the config files. But it seems as if there are some issues with Spring.
The new workflow therefore is:
create a new folder and class inside the /app directory
run spring stop on the command line
check the autoload-paths with bin/rails r 'puts ActiveSupport::Dependencies.autoload_paths' on the command line. The new folder should now be listed.
run spring start on the command line
In Rails 3, you can set this in config/application.rb, where this sample is provided by default:
# Add additional load paths for your own custom dirs
# config.load_paths += %W( #{config.root}/extras )
On Rails 5 you need to add the following code to environment.rb:
# Add the widgets folder to the autoload path
Rails.application.configure do
config.autoload_paths << "#{Rails.root}/app/widgets"
end
Another update for rails 3 -- activesupport 3.0.0:
Instead of:
ActiveSupport::Dependencies.load_paths << "#{RAILS_ROOT}/app/widgets"
You may need to do this:
ActiveSupport::Dependencies.autoload_paths << "#{RAILS_ROOT}/app/widgets"
I found I needed to do this after config block-- no access to config object anymore.
This did the trick
ActiveSupport::Dependencies.load_paths << "#{RAILS_ROOT}/app/widgets"
In config/application.rb add config.autoload_paths << "#{config.root}/models/widgets".
File should look like this:
module MyApp
class Application < Rails::Application
config.autoload_paths << "#{config.root}/models/widgets"
end
end
I know this works for Rails 4 and 5. Probably others as well.
If you want to add multiple directories:
config.autoload_paths += Dir[Rails.root / "components/*/app/public"]
(this is an example for packwerk autoload)
Related
I am working on this rails application with an engine which is sort of sub application adding some more routes to my existing application.
The concept is so powerful, thanks to rails.
But I am facing this weird challenge to autoload file changes inside my engines lib directory in development mode. Every time I make a change inside app directory of engine be it model or controller , it works flawlessly, but no changes to any files under lib directory get's picked up. Is there a way I can do this ? Thanks for your help.
According to Rails::Engine docs you can autoload paths like-
class MyEngine < Rails::Engine
# Add a load path for this specific Engine
config.autoload_paths << File.expand_path("../lib/some/path", __FILE__)
initializer "my_engine.add_middleware" do |app|
app.middleware.use MyEngine::Middleware
end
end
If you don't want to autoload, you can directly require the file in your class with the require statement-
require 'my_engine/my_object'
class MyModel < AR::Base
...
end
This will work because your Engine is already loaded in your app, so you can access libs inside of it.
Put the following code in your config/application.rb
config.eager_load_paths += ["#{Rails.root}/lib"]
If you want this only in development mode use the following
config.eager_load_paths += ["#{Rails.root}/lib"] if Rails.env.development?
In my Rails project, I want to add services directory in app folder and include some service objects.
So let's say I want to add app/services/foo/test.rb which looks like:
module Services
module Foo
class Test
end
end
end
In my config/application.rb I added:
config.paths.add File.join('app', 'services'), glob: File.join('**', '*.rb')
config.autoload_paths += Dir[Rails.root.join('app', 'services', '*')]
However when I try to load the files in console it doesn't work:
⇒ rails c
Loading development environment (Rails 4.1.4)
[1] pry(main)> Services::Foo::Test
NameError: uninitialized constant Services
Any help how can I solve this issue?
After add new dir, reload spring
spring stop
First of all, the code under app folder will be loaded without any config.
I think the problem was the folder structure doesn't match with your class definition.
So this config will work:
app/services/foo/test.rb
module Foo
class Test
end
end
My clue is, for example we have app/controllers/api/v1/users_controllers.rb and the class constant will be Api::V1::UsersController, not Controllers::Api::V1::UsersController
Update
Conventionally, we usually use FooServices instead of Foo, it is clearer, for example:
app/services/foo_services/bar_parser.rb
module FooServices
class BarParser
# Do stuff
end
end
So we understand that every class inside foo_services folder is a service which related to Foo
My problem was because of Rails naming conventions, I suppose. I just renamed class to not use module Services and it worked.
I have many service objects in my service folder. I'm using Rails 4:
->services
a_gen.rb
b_gen.rb
...
a_pro.rb
b_pro.rb
...
I would like my folder structure to be something like
->services
->gen
a_gen.rb
b_gen.rb
...
->pro
a_pro.rb
b_pro.rb
...
I tried just making the folders and putting the objects there, but Rails complains about not able to find it. Do I have to tell rails to look there?
Update:
I am getting this error:
NameError - uninitialized constant ExampleModelName::APro
Even with the path loaded. Once it is in the subfolder.. Rails is looking into the wrong place.
You can do that in two ways.
If you want rails to autoload them without you making any modifications to the config.autoload_paths, define your classes per the folder structure as follows:
module Gen
class ServiceA
end
end
If you don't want to make any changes to your class definition, then you could add those sub folders to the config.autoload_paths as follows in your config/application.rb
module YourApplication
class Application < Rails::Application
config.autoload_paths += [
"#{Rails.root}/app/services/gen",
"#{Rails.root}/app/services/prod"
]
end
end
for a recursive solution
# application.rb
config.autoload_paths += Dir["#{config.root}/app/services/**/"]
Yes, you do. In config/application.rb, you can add the subfolders to the config.autoload_paths collection.
Usually I add the following in config/application.rb to add autload_paths:
config.autoload_paths += Dir[Rails.root.join('app', 'poros', '{**}')]
How can I achieve the same in an engine?
It seems to work when I just use the same code in application.rb in the host app, however I think it's ugly that the code is not in the engine and needs to be added to the host app to make things work.
The only solution I found to add the load path through the engine is by adding this to lib/engine/engine.rb:
config.to_prepare do
Dir.glob(Rails.root + "../../app/poros/**/*.rb").each do |c|
require_dependency(c)
end
end
However there seems to be something fundamentally wrong with this as this leads to problems when I'm doing console reloads (e.g. it tells me that constants are already defined or that concerns can't execute the include block twice)
What is the right way to do this in the engine itself? (can't believe this is so hard/uncommon, I have really googled a lot but I can't find a solution)
According to the Rails::Engine documentation, you can add autoload paths in your Railtie like this:
class MyEngine < Rails::Engine
# Add a load path for this specific Engine
config.autoload_paths << File.expand_path("../lib/some/path", __FILE__)
initializer "my_engine.add_middleware" do |app|
app.middleware.use MyEngine::Middleware
end
end
If poros is a subdirectory of app, you do not need add it again.
All subdirectories of app in the application and engines present at boot time. For example, app/controllers. They do not need to be the default ones, any custom directories like app/workers belong automatically to autoload_paths.
I place a file name g.rb in side Rails.root/lib folder
The file content is like this:
module Google
end
Then I add
config.autoload_paths += %W(#{config.root}/lib #{Rails.root}/app/delayed_jobs)
to my Rails.root/config/application.rb
However, when I try to invoke Google from rails console, an exception is thrown. The exception goes away only if I execute require 'google'.
Why? Shouldn't my file is autoloaded and shouldn't I access the module without any extra require statement?
Hmm, I discovered an interesting thing. In order for Rails to auto load my class, the class name should be compliant to the file name and the folder structure.
For example, if I want to have Google module autoloaded, I must placed it inside google.rb, directly under /lib (incase I specify autoload from /lib).
If I want to auto load Google::Docs, then I either place it inside google.rb or google/docs.rb
I had a similar problem with getting my module to run on Heroku. In addition to the autoload naming convention stated by Stephen C, I found out that the module code must be require'd due to a threadsafe assumption made by the Rails' production environment on Heroku (even though threadsafe was commented out in my production.rb configuration file.) As soon as I require'd the module file before calling include on the module, everything started to work.
require 'mymodule'
include Mymodule
Please take a look at this excellent article on the subject of getting Modules to load correctly in Heroku (production).
That's because the point of autoload is not to 'require' everything up front (startup penalty). Classes are loaded as they are needed/referenced. In order to do this, you need some way to know where to look for the class. Otherwise, you would have to load every file in the autoload directory in advance to see what classes are declared. It's a tradeoff, but requiring everything in advance (as marbaq suggests) is not autoloading.
You can use the autoload command as provided by Ruby, which takes two arguments, the module to load (symbolized, i.e. :Google in your case), and the second argument is the filename, which would be g.rb if lib is in your load path ($:). See the Ruby docs for autoload.
Change config.autoload_paths to config.eager_load_paths
(based on Rails issue #6850 and Force reload! from lib directory in rails 3.2 console)
I faced the same problem just now, and my "solution" (or rather workaround) was to manually require every needed file from Rails.root/lib in my application.rb.
require 'lib/message'
require 'lib/store'
require 'lib/vault/vault.rb'
require 'lib/custom_loggers'
module MyApplication
class Application < Rails::Application
My next step would be to categorize the files in module folders as you mention.
i found this solution recently
config/application.rb
module AppName
class Application < Rails::Application
# Custom directories with classes and modules you want to be autoloadable.
config.autoload_paths += Dir[Rails.root.join('app', 'models', '{**}')]
config.autoload_paths += Dir[Rails.root.join('app', 'lib', 'extensions')]
end
end
the first config call induces rails to auto-load all sub-directories of the app/models directory
so now i can have /app/models/sub_directory/model.rb auto-loaded
(handy for organising an app with a large code base)
the second config call induces rails to autoload the lib/extensions directory
hope this helps
note: i believe this is rails 3 specific