Broken static image links in emails with ruby on rails

Question

I had broken images in gmail, I was doing nothing fancy, just things like:

image_tag "logo.png"

but the paths were relative or started with // instead of https:// or http://.

Answer 1

I ended up doing:

In config/application.rb:

    if ENV["HOST"].present?
      config.action_mailer.default_url_options = { host: ENV.fetch("HOST") }
    end

    if ENV["BASE_URL"].present?
      config.action_controller.asset_host = ENV.fetch("BASE_URL")
      config.action_mailer.asset_host = ENV.fetch("BASE_URL")
    end

In config/initializers/default_url_options.rb:

if ENV["HOST"].present?
  Rails.application.routes.default_url_options[:host] = ENV.fetch("HOST")
  ActionMailer::Base.default_url_options = { host: ENV.fetch("HOST") }
end

with:

HOST=socializus.app
BASE_URL=https://socializus.app
# HOST=localhost:3000
# BASE_URL=http://localhost:3000