I'm having some trouble to namespace a module that I include in a model.
in /app/models/car.rb
class Car
include Search::Car
end
in /lib/search/car.rb
module Search
module Car
include ActiveSupport::Concern
# methods in here
end
end
in /config/application.rb
config.autoload_paths += Dir["#{config.root}/lib/**/"]
config.autoload_paths += Dir["#{config.root}/lib/search/*"]
The weird thing is that I don't get any errors directly when I fire up the server.
But if I refresh the browser after a while I get this error:
Expected #{Rails.root}/lib/search/car.rb to define Car
The nature of the problem indicates that it has something to do with:
/config/environments/development.rb
config.cache_classes = false
I also tried put a file search.rb directly in /lib where I define Search:
module Search
# Put shared methods here
end
What am I doing wrong?
UPDATE:
Ok, turns out that if I rename Search::Car to Search::CarSearch it works.
Is it not possible to have Modules/Classes of the same name in a different scope?
The error is coming from your autoload_paths. config.autoload_paths += Dir["#{config.root}/lib/**/"] will add all directories and their subdirectories under lib directory. meaning that you are telling rails to autoload lib/search/ directory, therefore car.rb under that directory is expected to define Car and not Search::Car. In order for rails to expect lib/search/car.rb to define Search::Car, you need to autoload lib/ directory and not lib/search. if you change you autoload to config.autoload_paths += Dir["#{config.root}/lib/"] and put search.rb in lib/ with following code:
module Search
require 'search/car'
end
then rails will understand and expect lib/search/car.rb do define Search::Car and referencing Car module/class in other places of your code will not reference to this car.rb.
You should remove this line (you should only have autoload for lib directory):
config.autoload_paths += Dir["#{config.root}/lib/search/*"]
Related
I see that the following configuration in application.rb:
config.autoload_paths += %W(#{config.root}/app/models/custom_pack/base)
config.autoload_paths += Dir["#{config.root}/app/models/custom_pack/custom_container/**/"]
config.autoload_paths += Dir["#{config.root}/app/models/custom_pack/helpers/**/"]
config.autoload_paths += Dir["#{config.root}/app/models/custom_pack/extensions/**/"]
is in the autoload_paths:
Rails.application.config.autoload_paths.grep /custom/
=> ["/Users/dviglione/projects/core/app/models/custom_pack/base", "/Users/dviglione/projects/core/app/models/custom_pack/custom_container/", "/Users/dviglione/projects/core/app/models/custom_pack/helpers/", "/Users/dviglione/projects/core/app/models/custom_pack/extensions/"]
But these files are not being loaded. Because I get an error:
`method_missing': undefined method `create_element' for #<MyElement:0x007f82eca39898>
That create_element method is defined in one of the files that should have been loaded.
However, when I use require/require_relative, it does work:
# /initializers/my_initializer.rb
require "custom_pack/base"
# models/custom_pack/base.rb
require_relative 'custom_container/base'
require_relative 'custom_container/parent'
require_relative 'custom_container/child'
Dir[File.join(File.expand_path("../helpers", __FILE__), "*_helper.rb")].each { |file| require file }
Dir[File.join(File.expand_path("../extensions", __FILE__), "*_adapter.rb")].each { |file| require file }
From what I read from the documentation, when you use require 'erb', Ruby looks for the file in the directories listed in $LOAD_PATH. That is, Ruby iterates over all its directories and for each one of them checks whether they have a file called "erb.rb". If it finds any of them, the interpreter loads it and ends the search. Otherwise, it tries again in the next directory of the list. If the list gets exhausted, LoadError is raised. For autoloading, the idea is that when a constant like Post is hit and missing, if there's a post.rb file for example in app/models Rails is going to find it, evaluate it, and have Post defined as a side-effect. Rails has a collection of directories similar to $LOAD_PATH in which to look up post.rb. That collection is called autoload_paths.
So why does require/require_relative work, but autoload_paths does not?
There's a number of things that could be going on here.
1.If a file is following the path: lib/foo/bar.rb the class needs to be defined like:
class Foo::Bar
end
2.Autoload also lazy loads files, which means your models are only loaded when you call them. For example:
puts "I was loaded!"
class MyLibrary
end
irb(main):001:0> require 'mylibrary'
I was loaded!
=> true
irb(main):001:0> autoload :MyLibrary, 'mylibrary'
=> nil
irb(main):002:0> MyLibrary.new
I was loaded!
=> #<MyLibrary:0x0b1jef>
As for the actual usage of autoload, it's recommended to start using require instead. In theory autoload sounds nice but it can cause problems when certain classes are dependent on other modules. Because of this autoload is in the process of being deprecated.
I've created a file as lib/services/my_service.rb.
# /lib/services/my_service.rb
class MyService
...
end
I want to use it in app/controllers/my_controller
class MyController < ApplicationController
def method
service = MyService.new()
end
I'm getting an error that MyService is an uninitialized constant. I've tried to import it with
require '/lib/services/my_service.rb'
But I'm getting
cannot load such file -- /lib/services/my_service.rb
Edit: I have tried autoloading from application.rb using
config.autoload_paths << Rails.root.join('lib')
But no dice. Still getting uninitialized constant MyController::MyService
Ruby on Rails requires following certain naming conventions to support autoloading.
Rails can autoload a file located at lib/services/my_service.rb if the model/class structure was Services::MyService.
Change your lib/services/my_service.rb to:
module Services
class MyService
# ...
end
end
And use that class like this in your controller:
service = Services::MyService.new
Please note that depending on your Ruby on Rails version, you might need to add the lib folder to the list of folders which are queried when looking for a file to autoload:
# add this line to your config/application.rb:
config.autoload_paths << "#{Rails.root}/lib"
Read more about autoloading in the Rails Guides.
You probably need to enable the autoload from the files in the lib/ folder:
# config/application.rb
config.autoload_paths << "#{Rails.root}/lib"
If you prefer to do it "manually", then you can only require such file in the same file:
# config/application.rb
require './lib/my_service'
After this a restart is necessary.
there is a setting in config/application.rb in which you can specify directories that contain files you want autoloaded.
From application.rb:
# Custom directories with classes and modules you want to be autoloadable.
# config.autoload_paths += %W(#{config.root}/extras)
or
config.autoload_paths += Dir["#{config.root}/lib/**/"]
rails 3
Dir["lib/**/*.rb"].each do |path|
require_dependency path
end
Add this in your application.rb
config.eager_load_paths << Rails.root.join('lib/services')
Adding lib to config autoload paths does not autoload my module in Rails 3.
I add in my config/application.rb file.
config.autoload_paths += %W(#{config.root}/lib)
config.autoload_paths += Dir["#{config.root}/lib/**/"]
In my controller I added
require 'lib_util' (or)
include LibUtil #both doesn't work
In my lib/lib_util.rb file, I have the following module
module LibUtil
module ClassMethods
def p_key(a,b)
//mycode
end
end
def self.included(receiver)
receiver.extend ClassMethods
end
end
I get the error undefined method `p_key'. The important thing to be noted is I ve called the same module in my model it works fine. But in my controller it does not identify the module.
Can anybody guide me??
Did you try including both the modules ?
include LibUtil::ClassMethods
I'm currently migrating an application in rails v2 to v3
In my lib/ i've some modules in subdirectories, for example,
i've the lib/search/host_search.rb
with a
module HostSearch
def do_search(args)
#...
end
end
then I need to use it in a controller named Discovery::HostController < ApplicationController :
def search_results
output = HostSearch.do_search(:search_string => #search_string,
:page => params[:page],
:user => #current_user)
#...
end
But have I get:
uninitialized constant Discovery::HostController::HostSearch
..I tried to put this lines in application.rb but it doesn't work..
config.autoload_paths += %W(#{config.root}/lib)
config.autoload_paths += Dir["#{config.root}/lib/**/"]
I found that moving the module to the lib folder or explicitly including the folder to load worked, in your case
config.autoload_paths += %W(#{config.root}/lib/search)
I think there's something syntaxical that we are missing. Another thing is that if you don't want to mess with the application.rb file, require the file, which if I remember, takes the file path from the lib folder eg: search/host_search <- check that.
I think if you put the HostSearch module under a search subdir, (ie in lib/search/host_search.rb), then you need to namespace it:
module Search
module HostSearch
end
end
If you don't want to namespace it, you can should move the file into the lib root: lib/host_search.rb.
See also: https://stackoverflow.com/a/19650564/514483
I have a class ConstData:
class ConstData
US_CITIES = ['miami', 'new york']
EUROPERN_CITIES = ['madrid', 'london']
end
Its stored under /lib/const_data.rb
The idea is that inside a model, controller or view I can do:
ConstData::US_CITIES to get the US_CITIES etc
Rails should load this class automatically, I got this from:
http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/662abfd1df9b2612?hl=en
However this does not work. Can anyone explain me how to accomplish this ?
The post #daniel refers to is from 2008. Rails has changed since then.
In fact, quite recently. Rails3 doesn't load the lib/ directory automatically.
You can reactivate it quite easily though. Open config/application.rb And add, in the config (in the Application class) the followin :
config.autoload_paths += %W(#{config.root}/lib)
Then your lib/ dir will be autoloaded.
The reason autoload_paths didn't work for you and you were forced to do:
Dir["lib/**/*.rb"].each do |path|
require_dependency path
end
is because you forgot to namespace your class.
lib/awesome/stuffs.rb should contain a class/module like this:
class/module Awesome::Stuffs
....
but you had:
class/module Stuffs
....
Rails can only autoload classes and modules whose name matches it's file path and file name.
:)
config.autoload_paths did not work for me. I solved it by putting the following in ApplicationController:
Dir["lib/**/*.rb"].each do |path|
require_dependency path
end
Follow the solution for lib dir be autoloaded:
Remove config.threadsafe! from development.rb and production.rb;
Add in config/application.rb:
config.autoload_paths += %W(#{config.root}/lib)
config.threadsafe!
config.dependency_loading = true