After i include custom module inside model, annotate stop working and give me error:
My model: app/models/hotel.rb
class Hotel < ActiveRecord::Base
include HotelHandler
...
end
Custom helper class: app/helpers/hotel_handler.rb
module HotelHandler
...
end
This give me error:
uninitialized constant Hotel::HotelHandler (NameError)
If you want to setup Rails style auto and eager loading in a plain old Ruby project the modern way is to use Zeitwerk:
# this file would be the "entry path" to your application such as config.ru
# loads an installs gems inline
require 'bundler/inline'
gemfile do
source 'https://rubygems.org'
gem 'zeitwerk'
end
root = Pathname.new(File.expand_path(__dir__))
env = ENV.fetch("MYAPP_ENV", 'development')
loader = Zeitwerk::Loader.new
# Mimics Rails by adding every subdirectory of `/app` and `/app/**/concerns`
# as "root directories" where zeitwerk will find top level constants
paths = [
dir[root.join('app/*/')]
dir[root.join('app/**/concerns')]
].flatten.each do |path|
loader.push_dir(path) if File.directory?(path)
end
# makes zeitwerk reload classes when they change
loader.enable_reloading if env == 'development'
loader.setup
# loads all classes on boot for performance
loader.eager_load if env == 'production'
This is really just a quick and dirty minimal example and you would usually enscapsulate this logic into a bootstapping file and an "Application" class.
Related
Rails 5.2 here.
I want to test a class defined in app/lib/legacy/export.rb:
# app/lib/legacy/export.rb
module Legacy
class Export
def initialize ; end
end
end
However, a test in test/services/legacy_export_test.rb
# test/services/legacy_export_test.rb
require 'test_helper'
class LegacyExportTest < ActiveSupport::TestCase
test 'can be initialized' do
Legacy::Export.new
end
end
will spit out NameError: uninitialized constant Legacy::Export.
It works well if I put the class definition in app/lib/export.rb (and remove the module definition).
I can also reference this class in Controllers and in the rails console (rails c).
Trying to reference the class starting with the top-level-"namespace" (::Legacy::Export) does not help either. I find answers to questions how to reference lib folders (and subdirectories) in the test/ folder, but this is not what I need.
require 'lib/legacy/export will tell me cannot load such file, as will require 'legacy/export'.
I assumed that the (Auto-)Load-stuff of Rails and MiniTest are the same, but obviously there is some additional configuration to be done.
What has to be done? Where would I find this information?
The problem is that your class namespace / class path doesn't match how Rails autoloading works out of the box.
When you use a class that wasn't previously declared, Rails by default will look on specific paths (defined on config.autoload_paths)
app/controllers
app/controllers/concerns
app/models
app/models/concerns
...
When you use User for the first time, as it's not defined (yet) it will loop over those paths and try to require app/controllers/user.rb, app/controllers/concerns/user.rb, app/models/user.rb, until it founds the User class
if your class is namespaced as Legacy::Export, then it will look for app/models/legacy/export.rb, app/models/concerns/legacy/export.rb, app/controllers/legacy/export.rb, etc.
That's why it can't find your class: Your file is located on app/lib, that's not within the paths Rails use to look for.
There are different solutions:
Option #1
Require the file explicitly. (The Ruby way)
require_relative '../../app/lib/legacy/export'
Option #2
Add app/lib to autoload_path (in config/application.rb)
(The Rails Way)
module YourApp
class Application < Rails::Application
# ...
config.autoload_paths << Rails.root.join("app/lib")
end
end
Option #3
Adapt namespace to match what autoloading expects (instead of changing the configuration)
Example: move you file to something like app/models/legacy/export.rb
I'm building a Ruby gem that includes a module that's meant to monkey-patch the Hash class to add a new method. I'm following this guide to try to do it neatly: http://www.justinweiss.com/articles/3-ways-to-monkey-patch-without-making-a-mess/
I've placed the module in lib/core_extensions/hash/prune.rb, and the module is declared as such:
module CoreExtensions
module Hash
module Prune
##
# Removes all pairs from the Hash for which the value is nil. Destructive!
def prune!
self.reject! { |_, v| v.nil? }
end
end
end
end
And in order to make the monkey patch take effect, I'm calling this within the main gem file:
Hash.include(CoreExtensions::Hash::Prune)
But after building the gem and trying to require it in an irb console, I get the following error: NameError: uninitialized constant Gem::CoreExtensions (Gem is a placeholder name).
I made sure to include the prune.rb file in my gemspec's files array: s.files = ['lib/gem.rb', 'lib/core_extensions/hash/prune.rb'], so I'm not sure why it can't detect the file and its modules. Can anyone help me figure this out?
Thank you!
EDIT: In case it will help anyone else - I tried to require the module file using require 'lib/core_extensions/hash/prune' but received 'cannot load such file' errors. Sticking ./ in front of the path fixed it.
DEPRECATION WARNING: PaperTrail.track_associations has not been set. As of PaperTrail 5, it defaults to false. Tracking associations is an experimental feature so we recommend setting PaperTrail.config.track_associations = false in your config/initializers/paper_trail.rb . (called from require at /Users/george/.rbenv/versions/2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68)
Run options:
Since this is not a Rails app, there is no config/initializers/paper_trail.rb. Looked at https://github.com/airblade/paper_trail/blob/master/lib/generators/paper_trail/install_generator.rb, but didn't see a generator for the config file.
If I do
require 'paper_trail'
PaperTrail.config.track_associations = false
it still emits the warning.
Also tried:
def PaperTrail; end
PaperTrail.config.track_associations = false
require 'paper_trail'
This is a "Classic" Sinatra app.
The reason why this is happening is due the the call to require 'paper_trail' initializing a PaperTrail.config object: this line results in this file getting required, a part of which gets executed resulting in initializing the config singleton. We can solve this by first setting up the config object and then requiring the top-level paper_trail file later.
# app.rb
require 'sinatra'
require 'paper_trail/config'
config = PaperTrail::Config.instance
config.track_associations = true
# require models here
Dir["#{Dir.pwd}/models/*.rb"].each { |file| require file }
# rest of app code
And the models won't need any change:
# models/article.rb
require 'paper_trail'
class Article < ActiveRecord::Base
has_paper_trail
end
Thus, when the require 'paper_trail' call gets executed, we already have the correct configuration setup and the warning won't be displayed.
I added PaperTrail.config.track_associations = false to config/application.rb in the definition of class Application.
I'm currently working on a script (command line tool) for work to help me manage expose consoles.
At first I was passing three arguments to the script each time I used it to login into the consoles, for example:
$ nexose-magic.rb -u user -p password -i 192.168.1.2 --display-scans
It's not very efficient, so I created a config.yml file that stores console information in a hash.
$ nexpose-magic.rb -c console --display-scans
I believe the tool will be useful to admins out there, so I'd like to share it in a gem. I can't figure out how to get my config.yml file to work with a gem install..It can't find the config.yml file! It's easy to point it at the relative path in my development directory, but once I create a gem that relative path isn't so relative anymore. How do I point nexpose-magic.rb at the config.yml file?
Is there a better way to handle something like this?
You can create a gem that include a configure class. This class has a load method that will take a directory as an argument. Then, you can pass the directory where you are currently working.
A nice way of preparing your gem is to create a Configuration singleton class in your gem:
require 'singleton'
class Configuration
include Singleton
attr_accessor :config, :app_path
def load(app_path)
#app_path = app_path
#load the config file and store the data
#config = YAML.load_file( File.join(#app_path,'config','config.yml'))
end
end
In your main class :
module MyFancyGem
class << self
#define a class method that configure the gem
def configure(app_path)
# Call load method with given path
config.load(app_path)
end
# MyFancyGem.config will refer to the singleton Configuration class
def config
MyFancyGem::Configuration.instance
end
end
end
Usage:
-Working directory
- my_new_script
- Gemfile
- config/
- config.yml
In my_new_script :
require 'bundler'
Bundler.setup(:default)
require 'my_fancy_gem'
MyFancyGem.configure(File.join(File.dirname(__FILE__),"./")) #here, you define the path
MyFancyGem.hello_world
I hope that's clear enough. I was actually about to write a blog post to explain this particular point (I hope in a more complete version of it). Let me know if you're interested !
I'm trying to use two Gems to access Amazon Web Services (AWS). One is the Amazon 'aws-sdk', the other is 'amazon-ec2'. I'm using the second as the aws-sdk does not cover the cloudwatch section of the amazon services.
The issue is that both load into the same namespace.
require 'aws-sdk' # aws-sdk gem
require 'AWS' # amazon-ec2 gem
config = {:access_key_id => 'abc', :secret_key => 'xyz'}
# start using the API with aws-sdk
ec2 = AWS::EC2.new(config)
# start using the API for anazon-ec2
cw = AWS::Cloudwatch::Base.new(config)
Now this understandably throws an error on the last line as the AWS module is pointing at the first required library, in this case aws-sdk.
NameError: uninitialized constant AWS::Cloudwatch
So, is it possible for me to load one of those into another namespace? Something like
require 'aws-sdk', 'AWS_SDK'
require 'AWS', 'AWS_EC2'
ec2 = AWS_SDK::EC2.new(config)
cw = AWS_EC2::Cloudwatch::Base.new(config)
Or is there another trick I could use here?
Thanks
In Ruby, modules with the same name from different gems don't replace each other. If one gem implements
module AWS
class Foo
end
end
and another implements
module AWS
class Bar
end
end
and you require them both, you will end up with an AWS module that contains both a class Foo and a class Bar (unless the second does something really tricky like explicitly undefining anything already present in the module, before defining its own stuff, which is very unlikely). As long as the second gem doesn't redefine any methods in the first gem (or attempts to use a module as a class or vice versa), they should both work fine. I think you may be looking for the wrong solution.
Edit:
And in fact, what happens for me (in an environment with only these gems present (aws-sdk 1.2.3 and amazon-ec2 0.9.17) and the exact code you listed above) is exactly that:
.rvm/gems/ree-1.8.7-2011.03#ec2/gems/amazon-ec2-0.9.17/lib/AWS/EC2.rb:2: EC2 is not a module (TypeError)
Could it be that an error gets swallowed somewhere and that the module AWS::Cloudwatch hasn't been defined, simply because the initialization of the gem goes awry?
I think I've found a solution that works, let me illustrate it with an example. Suppose we have to files a.rb and b.rb that define the same module with actual name clashes:
#file a.rb
module A
def self.greet
puts 'A'
end
end
#file b.rb
module A
def self.greet
puts 'other A'
end
end
If you need to require both of them, the following seems to do the trick:
require_relative 'a'
TMP_A = A.dup
A.greet # => A
TMP_A.greet # => A
require_relative 'b'
TMP_A2 = A
A.greet # => other A
TMP_A2.greet # => other A
TMP_A.greet # => A
Without the dup, TMP_A will also point to the A defined in b.rb after the require_relative, but the dup will ensure that a real copy is produced instead of simply holding a reference to the module.