ActionView::Template::Error: Missing host to link to! Please provide the :host parameter, set default_url_options[:host], or set :only_path to true

Question

My ruby on rails action mailer runs all good in development environment, but in production environment, it keeps throw:

ActionView::Template::Error: Missing host to link to! Please provide the :host parameter, set default_url_options[:host], or set :only_path to true

My development config is

config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  :port           => xxx,
  :address        => 'smtp.example.org',
  :user_name      => '[email protected]',
  :password       => 'xxxxxxxx',
  :domain         => 'xxxxxx.example',
  :authentication => :plain,
}

config.action_mailer.default_url_options = { :host => 'localhost:3000' }

My production config is

config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  :port           => 587,
  :address        => 'smtp.example.org',
  :user_name      => '[email protected]',
  :password       => 'xxxxxx',
  :domain         => 'example.com',
  :authentication => :plain,
}
config.action_mailer.default_url_options = { :host => 'example.com' }

My other environments are:

ruby 2.1.1
rails 4.0.3
sidekiq
devise
devise-async

I have tried:

1. Add the following in a initializer file

   ActionMailer::Base.default_url_options[:host] = "example.com"
   

2. This answer here

Neither of them works.

Forereach

This is strange. I just got the same error and adding config.action_mailer.default_url_options = { :host => "example.com" } to my application.rb resolved the issue... Are you sure your config is picked up correctly? – Steamy

Answer 1

In the end I added the following with the correct value to each environment file:

test.rb / development.rb / production.rb

Devise 3.2.x - 4.x.x

Rails 4.1.x && Rails 4.2.x && Rails 5.x.x

Thanks to maudulus

# Default Mailer Host
  Rails.application.routes.default_url_options[:host] = 'domain.example'

Uproar

Thanks for the solution. I was able to load from an ENV variable. Rails 4.1.7. – Coprophagous

Awesome I'm glad that has been updated. Thanks for the comment. – Uproar

Finally a solution that works, this question is a perfect example where most results on Stackoverflow are simply outdated or just bad. – Addington

This was the correct answer for me for Rails 5.0.0 and Devise 4.2.0 – Boschvark

Thanks ! The only solution that worked in my case (Rails 5.0) ! – Freeliving

I don't get what the problem is at heart? What is a missing host? Why doesn't it infer the host? – Iorgos

Finally, a solution that helped me that wasn't setting config.default_url_options = { :host => 'localhost' } – Horten

Answer 2

Try restarting the server. Even in Rails 4.1 the config is not reparsed without a restart.

Joanne

Alongside this, if you're triggering mail actions from the console, you might need to restart the console too. – Moralize