Invalid delivery method :letter_opener

[sappapp]

I have set the following setting in development.rb

Mailing Configuration Parameters

config.action_mailer.delivery_method = :letter_opener ActionMailer::Base.perform_deliveries = true ActionMailer::Base.raise_delivery_errors = false

Yet I am still receiving an error. Do you have any suggestions?

[nashby]

did you restart your server after adding letter_opener to the Gemfile and running bundle install?

[sappapp]

Yes, all of the proper steps have been taken. I've been running around in circles on this for a while.

I am also using the devise gem. Would this cause any interference?

[nashby]

@sappapp I don't think so. Could you please provide sample app that reproduces this issue?

[hieuk09]

I got the same problem. My app is upgraded from Rails 2 to Rails 3. In Rails 2, the gem worked normally but in Rails 3 we got with the error "RuntimeError: Invalid delivery method :letter_opener". I used the gem many times before, it works well. Any help to resolve the problem?

RuntimeError: Invalid delivery method :letter_opener
    from /Users/eastagile/.rvm/gems/ruby-1.9.3-p392@myproject/gems/actionmailer-3.2.11/lib/action_mailer/delivery_methods.rb:72:in `wrap_delivery_behavior'
    from /Users/eastagile/.rvm/gems/ruby-1.9.3-p392@myproject/gems/actionmailer-3.2.11/lib/action_mailer/delivery_methods.rb:84:in `wrap_delivery_behavior!'
    from /Users/eastagile/.rvm/gems/ruby-1.9.3-p392@myproject/gems/actionmailer-3.2.11/lib/action_mailer/base.rb:641:in `mail'
    from /Users/eastagile/.rvm/gems/ruby-1.9.3-p392@myproject/gems/sendgrid-1.2.0/lib/sendgrid.rb:168:in `mail'
    from /Users/eastagile/code/myproject/app/mailers/emails.rb:964:in `full_service_signup_email'
    from /Users/eastagile/.rvm/gems/ruby-1.9.3-p392@myproject/gems/actionpack-3.2.11/lib/abstract_controller/base.rb:167:in `process_action'

[nashby]

@hieuk09 Since I can't reproduce it could you please create a sample app that reproduces your problem? Thanks.

[hieuk09]

I couldn't reproduce it in another app ether. However, I solved this by adding

require 'letter_opener' if Rails.env.development?

into config/application.rb It seems that the gem does not automatically load.

[ghost]

rm -rf .bundle fixed it for me

[guinslym]

Thanks @theuri

[itsNikolay]

got the same error because I have deleted the gem from Gemfile, so add:

# Gemfile
gem 'letter_opener'

[inix]

rm -rf .bundle fixed it for me

This solution works for me.