Where can I store site-wide variables in Rails 4? - ruby-on-rails

I am new to Rails and come from a ColdFusion background, where we would store global / site-wide variables in the 'application' scope. This persists the variable across any view or controller. Does Rails 4 have an equivalent functionality for this type of thing?
The site-wide variable won't typically change often so it doesn't need protecting in any way.
For example, in my situation, I want to store the website's domain name. One for testing and one for live environments. Localhost for development and xxxxxx.com for production.
Any tips or pointers would help. I have Googled this extensively and solutions seem to be far too complicated to achieve what seems to be such a trivial task. What's the best elegant solution for Rails 4?

The simplest, basic and default way is to use the Rails.application.config store.
Rails.application.config.my_config = 'foo'
You can assign a config in your environment:
# application.rb
module MyApp
class Application < Rails::Application
config.my_config = 'foo'
end
end
and read it with
Rails.application.config.my_config
# => 'foo'
This approach works well for very simple applications, but if you want something more advanced there are several gems available.
I'm currently using SimpleConfig. The main advantages are:
per-environment configuration. You can configure default configurations for the application, then override defaults with environment specific configurations
local.rb file for custom overrides
capistrano-like configuration style
it works nicely with the dotenv gem, very useful to avoid storing sensitive credentials in your repo.

This sounds like a perfect example for configuration values stored in config/environments/production.rb and config/environments/development.rb. Just store any value there:
config.my_special_value = 'val'
And access it in your application like this:
Rails.application.config.my_special_value
Always the value of your environment is active.
If you just want to have a „global“ value, store it in your application controller. All your view controllers are derived from your app controller, so you can save any value there as an instance or class variable:
class ApplicationController < ActionController::Base
MY_CONSTANT_VALUE = "foo"
end
class MyViewController < ApplicationController
def index
raise MY_CONSTANT_VALUE.inspect
end
end
You also could implement an helper:
# app/helpers/application_helper.rb
module ApplicationHelper
FOO = "bar"
end
# app/controllers/foo_controller.rb
class FooController < ApplicationController
def index
raise FOO
end
end

I can recommend good method to store variable. I use this on production
Passwords can be stored easier to .env file
like this
#Root dir create file ".env"
PASSWORD=123456
and load password
#Somewhere in app
ENV['PASSWORD'] #=> 123456
it works I hope will help you

You can use gem figaro
write your variables in config/application.yml
HELLO: world
development:
HELLO: developers
production:
HELLO: users
Then you can fetch
ENV["HELLO"]

In rails there is gem named as
gem 'dotenv-rails'
By using it we can assign the variables to system level and used in application.
By using simple steps
First create a simple filed in system level at any place with named extension .env
//in application.rb
require 'dotenv'
Dotenv.load('path-of-your-file.env')
And restart your application
Source
Please got the link for the desscription of dot env gem

Related

Where is a good place to initialize an API?

I wanted to use this api: https://github.com/coinbase/coinbase-ruby and the first step is to initialize the API, like this:
coinbase = Coinbase::Client.new(ENV['COINBASE_API_KEY'], ENV['COINBASE_API_SECRET'])
I was wondering what the best place to put this code is, and how would I access it if I put it "there"? I want this variable (coinbase) to be accessible ANYWHERE in the application.
Thanks!
The answer to this question really depends on your use case and your approach. My geral recommendation, however, is to create a Service Object (in the DDD sense) (see the section named "Domain Objects Should Not Know Anything About Infrastructure Underneath" in that link), that handles all communication with the Coinbase API. And then, within this service object, you can simply initialize the Coinbase::Client object once for however many times you call into it. Here's an example:
# app/services/coinbase_service.rb
class CoinbaseService
cattr_reader :coinbase_client, instance_accessor: false do
Coinbase::Client.new(ENV['COINBASE_API_KEY'], ENV['COINBASE_API_SECRET'])
end
def self.do_something
coinbase_client.do_something_in_their_api
end
def self.do_something_else
coinbase_client.do_something_else_in_their_api
end
end
So then you might do, e.g.:
# From MyController#action_1
if CoinbaseService.do_something
# ...
else
# ...
end
Or:
# From MyModel
def do_something
CoinbaseService.do_something_else
end
To get the service object working, you may need to add app/services to your autoload paths in application.rb file. I normally just add this:
# config/application.rb
config.autoload_paths += %W(#{config.root}/app)
I find this Service Object approach to be very beneficial organizationally, more efficient (only 1 invocation of the new Coinbase client needed), easier to test (easy to mock-out calls to Coinbase::Client), and simply joyful :).
One way to go about having a global variable can be done as similar as initializing redis in a Rails application by creating an initializer in config/initializers/coinbase.rb with:
$coinbase = Coinbase::Client.new(ENV['COINBASE_API_KEY'], ENV['COINBASE_API_SECRET'])
Now, you can access $coinbase anywhere in the application!
In the file config/initializers/coinbase.rb
Rails.application.config.after_initialize do
CoinbaseClient = Coinbase::Client.new(
Rails.application.credentials.coinbase[:api_key],
Rails.application.credentials.coinbase[:api_secret])
end
In place of the encrypted credentials, you could also use environment variables: ENV['COINBASE_API_KEY'], ENV['COINBASE_API_SECRET']
The above will make the constant CoinbaseClient available everywhere in your app. It will also ensure all your gems are loaded before the client is initialized.
Note: I am using Rails 6.1.4.4, and Ruby 2.7.5

Global variable not working in production

I have the following pair of controllers:
Admin::BaseController - used in the backend of the application.
Base::BaseController - used in the frontend of the application.
In Admin::BaseController I set the following global variable:
$FRONTEND = false
In Base::BaseController I set it as follows:
$FRONTEND = true
I do this so that I can do the following in various models:
def to_param
If $FRONTEND
...
else
...
end
end
This works in development but not in production. I know that I should probably not be using global variables anyway. What's a good alternative to this?
create environment variable instead of that.
such as env['name ur variable']=value in environment.rb file
You can use the Figaro gem to set Environment variables. Check it out here: https://github.com/laserlemon/figaro
It allows you to set dev and production variables really easily.
You can then access them using ENV['name'] and the gem mentioned also adds them to your Heroku account too (Assuming you're hosting on Heroku)

Rails mountable engine: how should apps set configuration variables?

I have a mountable engine called Blog that apps can use.
What's the best way to allow apps that use the engine to set a configuration variable like site_name (so that the engine can display it in the design)?
Update:
I've seen some gems create a 'config/initializers/gem_name.rb' file. Is there any specification on how to:
Create a file like that on the engine's side
Copy it into the app's side
How to access those set variables on the engine's side?
I tried creating Blog.site_name = "My Site" in the app's config/initializers/blog.rb file but get an Undefined method error.
Figured out an even better solution that also allows you to set default values (incase the app using the engine doesn't specify a config)...
Create config variables in your app's /config/initializers/blog.rb like this:
Blog.setup do |config|
config.site_name = "My Site Name"
end
In your engine's /lib/blog/engine.rb set default values like this:
module Blog
self.mattr_accessor :site_name
self.site_name = "Site Name"
# add default values of more config vars here
# this function maps the vars from your app into your engine
def self.setup(&block)
yield self
end
end
Now you can simply access the config variables in your engine like this:
Blog.site_name
Much cleaner.
After a lot of testing and looking into existing gems, here is what works in Rails 4:
Considering your engine's name is Blog:
In your engine's /lib/blog/engine.rb put in this:
module Blog
def self.setup(&block)
#config ||= Blog::Engine::Configuration.new
yield #config if block
#config
end
def self.config
Rails.application.config
end
end
In your app, create a file called /config/initalizers/blog.rb and set config vars like this:
Blog.setup do |config|
config.testingvar = "asdfasdf"
end
Then you can access these config variables ANYWHERE in your engine like this:
Blog.config.testingvar
Hope this helps someone. There is very little documentation on this right now so it was all trial and error.
I know this is a fairly old post, but in the event someone in the future finds this, I'd like to recommend the Angostura gem for passing dependencies into a Rails engine. To use it, assuming my engine is called 'Blog' and I want to access a variable called 'site_name', the engine's lib/blog.rb looks something like:
require "blog/engine"
require "angostura"
module Blog
include Angostura::Dependencies
dependency :site_name
end
In my main app, in config/initializers/blog.rb, I added
Blog.setup do |config|
config.site_name = "My site name"
end
Now, I can access site_name in my engine by calling Blog.site_name.
I'd like to point out that defaults are also supported, so you could do something like dependency site_name: 'Default site name' in lib/blog.rb. Furthermore, you can pass in whole classes as dependencies by sending it stringified classnames, like config.my_class = 'MyClass'.
For posterity, in order to use the gem, I added s.add_dependency "angostura", "0.6.0" in my engine's gemspec, and then ran bundle install.

Accessing config from application.rb in Controller (Rails 3)

I'm trying to add two extra config options to my application.rb so I can read them out in controllers.
# Extra
config.twitter.key = 'foo'
config.twitter.secret = 'bar'
I am trying to access them using three suggested methods:
self.config.twitter.key # Should be extended through ApplicationController Base
config.twitter.key # Inherited but with different syntax
CONFIG['twitter']['key'] #some massive magical array that apparently exists somewhere
They all give me different kinds of error when I pass them through the "debug" method, E.g:
debug self.config.twitter.key # undefined method `key' for nil:NilClass
So, whats going on?
I believe you've got a slightly incorrect idea behind what your expectations for the config/application.rb is providing you. The ActiveRecord::Base and ActiveController::Base eigenclasses use the Rails::Application::Configuration class that is configured in config/application.rb. The attributes aren't available in classes that descend from either of the Base classes, nor their eigenclasses. This is why you are running into errors in ApplicationController.
There are generally two ways to make configuration initializations in a Rails app. The first way is to create a configuration module and then load values into it via initializer:
First, create a Twiter Config module:
#lib/twitter_config.rb
module TwitterConfig
def self.config
##config ||= {}
end
def self.config=(hash)
##config = hash
end
end
Create a YAML config file:
# config/twitter.yaml
development: &base
key: "foo"
secret: "bar"
test:
<<: *base
key: "foo2"
production:
<<: *base
secret: "barbar"
Alternatively, if you don't intend to add config/twitter.yaml to your SCM, you can just skip this and set the key and secret via environment variables. This would be the suggested solution for an application with a public SCM repository deploying on Heroku.
Then load and set the value via an initializer:
#config/initializers/01_twitter.rb
require 'twitter_config'
TwitterConfig.config = YAML.load_file("config/config.yml")[Rails.env].symbolize_keys
It's generally a best practice to number your initializer files as Rails will load them in order according to their filename. If you are initializing a datastore and that is critical for other steps, then it needs the lowest number. Alternatively, if you are using environment variables, this would be the init file:
#config/initializers/01_twitter.rb
require 'twitter_config'
TwitterConfig.config[:key] = ENV['twitter_config_key']
TwitterConfig.config[:secret] = ENV['twitter_config_secret']
Throughout the Rails application, you now have access to the config values with TwitterConfig.config[:key] & TwitterConfig.config[:secret]. You can include the module as well, just watch out for conflicts.
You can also just load the values as a global constant. It feels a bit ugly to me though:
#config/application.rb
TWITTER_CONFIG = YAML.load_file("config/twitter.yaml")[Rails.env]
I've tried this and seems to be working, you can use ::Rails.application.config.
For example I'm using it to get the correct time_zone set in the application like this:
Rails.application.config.time_zone
I found it thanks to the less-rails code: https://github.com/metaskills/less-rails/blob/master/lib/less/rails/helpers.rb
So you can declare this in your application.rb or in any enviroment file:
config.twitter_key = 'foo'
And then read it like so anywhere in your code:
Rails.application.config.twitter_key
You might want to consider using a yaml file approach.
In application.rb
CONFIG = YAML.load_file("config/config.yml")[Rails.env]
In config/config.yml
development: &base_config
twitter_key = "foo"
twitter_secret = "bar"
test:
<<: *base_config
twitter_key = "foo2"
production:
<<: *base_config
twitter_secret = "barbar"
Same usage as before with definable attributes on an environment level with overloading.
CONFIG['twitter_key']
A small update to the widely accepted answer here : Accessing config from application.rb in Controller (Rails 3)
The methods inside the module TwitterConfig should be class methods (or module methods if you prefer it that way). They can't be instance methods.
Sorry to put this in an answer, but I could not find a way to comment on that answer.
Just put a file in config/initializers/ like app_config.rb If you use ENV constant you can later on easily deploy to Heroku setting the values with the heroku config:add twitter_key=mypublickey command.
Something like this:
## config/initializers/app_config.rb
unless Rails.env.production?
ENV['twitter_key'] = 'foo'
ENV['twitter_secret'] = 'bar'
end
You keep your production keys out of revision control and don't need to dribble with YAML-files.

How to define custom configuration variables in Rails?

I was wondering how to add custom configuration variables to a Rails application and how to access them in the controller?
Secondly, I was planning to have S3 support for uploads in my application, if I wanted to add a yaml file with the S3 access, secret key, how do I initialize it in my Rails App and how do I access the values that I have defined in that config file.
In Rails 3, Application specific custom configuration data can be placed in the application configuration object. The configuration can be assigned in the initialization files or the environment files -- say for a given application MyApp:
MyApp::Application.config.custom_config_variable = :my_config_setting
or
Rails.configuration.custom_config_variable = :my_config_setting
To read the setting, simply call the configuration variable without setting it:
Rails.configuration.custom_config_variable
=> :my_config_setting
UPDATE Rails 4
In Rails 4 there a new way for this => http://guides.rubyonrails.org/configuring.html#custom-configuration
Update 1
Very recommended: I'm going with Rails Config gem nowadays for the fine grained control it provides.
Update2
If you want a quick solution, then check Jack Pratt's answer below.
Although my original answer below still works, this answer is now outdated. I recommend looking at updates 1 and 2.
Original Answer:
For a quick solution, watching the "YAML Configuration File" screen cast by Ryan Bates should be very helpful.
In summary:
# config/initializers/load_config.rb
APP_CONFIG = YAML.load_file("#{Rails.root}/config/config.yml")[Rails.env]
# application.rb
if APP_CONFIG['perform_authentication']
# Do stuff
end
In Rails 3.0.5, the following approach worked for me:
In config/environments/development.rb, write
config.custom_config_key = :config_value
The value custom_config_key can then be referenced from other files using
Rails.application.config.custom_config_key
In Rails 4
Assuming you put your custom variables into a yaml file:
# config/acme.yml
development:
:api_user: 'joe'
:api_pass: 's4cret'
:timeout: 20
Create an initializer to load them:
# config/initializers/acme.rb
acme_config = Rails.application.config_for :acme
Rails.application.configure do
config.acme = ActiveSupport::OrderedOptions.new
config.acme.api_user = acme_config[:api_user]
config.acme.api_pass = acme_config[:api_pass]
config.acme.timeout = acme_config[:timeout]
end
Now anywhere in your app you can access these values like so:
Rails.configuration.acme.api_user
It is convenient that Rails.application.config_for :acme will load your acme.yml and use the correct environment.
This works in rails 3.1:
in config/environment.rb (or in config/environments/.. to target a specific environment) :
YourApp::Application.config.yourKey = 'foo'
This will be accessible in controller or views like this:
YourApp::Application.config.yourKey
(YourApp should be replaced by your application name.)
Note: It's Ruby code, so if you have a lot of config keys, you can do this :
in config/environment.rb :
YourApp::Application.configure do
config.something = foo
config.....
config....
.
config....
end
Since Rails 4.2, without additional gems, you can load config/hi.yml simply by using Rails.application.config_for :hi.
For example:
touch config/passwords.yml
#config/passwords.yml
development:
username: 'a'
password: 'b'
production:
username: 'aa'
password: 'bb'
touch config/initializers/constants.rb
#config/initializers/constants.rb
AUTHENTICATION = Rails.application.config_for :passwords
and now you can use AUTHENTICATION constant everywhere in your application:
#rails c production
:001> AUTHENTICATION['username'] => 'aa'
then add passwords.yml to .gitignore: echo /config/passwords.yml >> .gitignore, create an example file for your comfort cp /config/passwords.yml /config/passwords.example.yml and then just edit your example file in your production console with actual production values.
Rails 6 and 7
Many outdated answers, so adding one that is specific to Rails 6.
Application specific configuration goes in initializer files. Details are here: edge guides
Example:
config/initializers/foo.rb
module MyApp
class Application < Rails::Application
config.test_val = 'foo'
end
end
Alternatively:
Rails.application.config.test_val = 'foo'
This can now be accessed as:
Rails.configuration.test_val
Many more possibilities.
edge guides #custom-configuration
ex, you can also set up nested namespace configurations:
config.x.payment_processing.schedule = :daily
config.x.payment_processing.retries = 3
config.super_debugger = true
or use config_for to load entire custom config files:
config/payment.yml
production:
environment: production
merchant_id: production_merchant_id
public_key: production_public_key
private_key: production_private_key
development:
environment: sandbox
merchant_id: development_merchant_id
public_key: development_public_key
private_key: development_private_key
Then load it with:
config/initializers/load_payment.rb
module MyApp
class Application < Rails::Application
config.payment = config_for(:payment)
end
end
I just wanted to update this for the latest cool stuff in Rails 4.2, you can now do this inside any of your config/**/*.rb files:
config.x.whatever.you.want = 42
...and this will be available in your app as:
Rails.configuration.x.whatever.you.want
See more here: http://guides.rubyonrails.org/configuring.html#custom-configuration
Check out this neat gem doing exactly that:
https://github.com/mislav/choices
This way your sensitive data won't be exposed in open source projects
I created a simple plugin for YAML settings: Yettings
It works in a similar fashion to the code in khelll's answer, but you only need to add this YAML configuration file:
app/config/yetting.yml
The plugin dynamically creates a class that allows you to access the YML settings as class methods in your app like so:
Yetting.your_setting
Also, if you want to use multiple settings files with unique names, you can place them in a subdirectory inside app/config like this:
app/config/yettings/first.yml
app/config/yettings/second.yml
Then you can access the values like this:
FirstYetting.your_setting
SecondYetting.your_setting
It also provides you with default settings that can be overridden per environment. You can also use erb inside the yml file.
I really like the settingslogic gem. Very easy to set up and use.
https://github.com/binarylogic/settingslogic
If you use Heroku or otherwise have need to keep your application settings as environment variables, the figaro gem is very helpful.
I like to use rails-settings for global configuration values that need to be changeable via web interface.
Something we've starting doing at work is the ActiveSupport Ordered Hash
Which allows you to define your configuration cleanly inside the environment files e.g.
config.service = ActiveSupport::OrderedOptions.new
config.service.api_key = ENV['SERVICE_API_KEY']
config.service.shared_secret = ENV['SERVICE_SHARED_SECRET']
I would suggest good approach how to deal with configuration in your application at all. There are three basic rules:
change your configuration not a code;
use configurations over conditions;
write code that means something.
To have more detailed overview follow this link: Rails configuration in the proper way

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