How to Get the Host and Port in a Rails App

There are various ways to access the host and port in a Rails application. Here are three common approaches:

1. Passing host and port from the controller to the model
2. Using environment variables
3. Using config.action_mailer.default_url_options

1. Pass from Controller to Model:

In this approach, the host and port are retrieved from the request object in the controller and passed to the model.

Controller:

def show
     host = request.host
     port = request.port
  @some_model = MyModel.new_with_url(host, port)
end

Model:

class MyModel < ApplicationRecord
      def self.new_with_url(host, port)
      	base_url = "http://#{host}:#{port}/"
     	# Use base_url in model logic
   end
end

2. Use Environment Variables:

Host and port can be stored as environment variables and accessed directly in the model or any other application part.

host = ENV[‘HOST’]
Port = ENV[‘PORT’]

This keeps the code decoupled from the request lifecycle and ensures flexibility across different environments.

3. Use config.action_mailer.default_url_options:

Host and port can also be configured in the respective environment files, such as

config/environments/production.rb:
config.action_mailer.default_url_options = { host: 'my.application.com', port: 80 }

These can then be accessed as follows:

host = Rails.application.config.action_mailer.default_url_options[:host]
port = Rails.application.config.action_mailer.default_url_options[:port]

This method is particularly useful for generating consistent URLs for system-generated links like emails.