Images not loading in emails with CDN Hosts url rails - ruby

Question

I recently moved all my app assets to CDN and everything is working fine. All images are loading in views. But my problem is my images are not loading in emails which I am sending from my application. I have specified my CDN Path in production.rb file also but still not working. When I inspect that image in email, I didn't even getting src for that image.
I am loading my images using image_tag.
Can anyone please help me on this:
Production.rb:
config.action_controller.asset_host = AssetsCdn.new
config.action_mailer.asset_host = AssetsCdn.new
config.action_mailer.default_url_options = { :host => 'localhost', :protocol => 'http' }
config.action_mailer.perform_deliveries = true config.action_mailer.raise_delivery_errors = false config.action_mailer.default :charset => "utf-8"
config.action_mailer.delivery_method = :smtp #:mailhopper
AssetsCdn Class:
require 'zlib'
class AssetsCdn
CSS_CDN = "cdn-css"
CSS_CDN_0 = "cdn-css0"
CSS_CDN_1 = "cdn-css1"
CSS_CDN_2 = "cdn-css2"
JS_CDN = "cdn-js"
JS_CDN_0 = "cdn-js0"
JS_CDN_1 = "cdn-js1"
JS_CDN_2 = "cdn-js2"
ASSETS_CDN = "cdn-assets"
ASSETS_CDN_0 = "cdn-assets0"
ASSETS_CDN_1 = "cdn-assets1"
ASSETS_CDN_2 = "cdn-assets2"
ALL = [CSS_CDN_0, CSS_CDN_1, CSS_CDN_2, JS_CDN_0, JS_CDN_1, JS_CDN_2, ASSETS_CDN_0, ASSETS_CDN_1, ASSETS_CDN_2]
def call(source, request = nil)
cdn_index = Zlib.crc32(source) % 3
if source.ends_with?('.css')
url("#{CSS_CDN}#{cdn_index}", request)
elsif source.ends_with?('.js')
url("#{JS_CDN}#{cdn_index}", request)
else
url("#{ASSETS_CDN}#{cdn_index}", request)
end
end
def url(cdn_subdomain, request = nil)
return "//#{cdn_subdomain}-#{localhost}:3000"
end
end
TIA.

Answer 1

action_mailer.assets_host doesn't accept protocol relative URLs. Instead URLs have to start with with a protocol like http:// or https://.
This makes kind of sense, because usually emails aren't opened in a browser and email clients are not able to inherit the protocol from a patent html document like browsers do.