My biggest gripe with ActionMailer is how difficult it is to generate URL’s. It’s common enough when sending an email that it includes a link. But ActionMailer, by default, gives you no access to
url_for and named routes. Ugh!
Even if you’re clever enough to do something like:
class ActionMailer::Base include ActionController::UrlWriter end
You’re still screwed as you need to know the host, port, protocol, etc. to generate links. These data can be set globally, but by far the easiest and most flexible way is to get them is from the
Passing around the
The request object, is (of course) only available to Controllers. So the data need to be passed from the Controller to the mailer, like:
class UsersController < ApplicationController def create ... if @user.save MyMailer.deliver_foo(..., request.host, ...) end end end
Of course, if you’ve read my previous post you know I HATE polluting my Controllers with business logic like this. I strongly prefer pushing this “triggered action” into the model:
class User after_create :send_email end
The cost of this is that I now need to past the
host, etc. down into my model so it can pass it on to the mailer! The Java Programmers over here just laugh at me for not having a real Dependency Injection framework, which they say would solve this handily. Some stupid Java framework solving this problem better than Rails?! This makes me MAD AS HELL!
Enter the Global Variable
Screw Dependency Injection. I’m going to use a Global Variable like every other God Fearing Rails programmer. His Excellency DHH said let there be
cattr_accessor and it was Good.
Step one, set the around-filter in your ApplicationController:
THERE IS NO STEP TWO
You don’t need to pass around host. You can generate URL’s in ActionMailer no problem. Let’s look at how this is done:
module UrlWriterRetardaseInhibitor module ActionController def self.included(ac) ac.send(:include, InstanceMethods) end module InstanceMethods def inhibit_retardase begin request = self.request ::ActionController::UrlWriter.module_eval do @old_default_url_options = default_url_options.clone default_url_options[:host] = request.host default_url_options[:port] = request.port unless request.port == 80 protocol = /(.*):///.match(request.protocol) if request.protocol.ends_with?("://") default_url_options[:protocol] = protocol end yield ensure ::ActionController::UrlWriter.module_eval do default_url_options[:host] = @old_default_url_options[:host] default_url_options[:port] = @old_default_url_options[:port] default_url_options[:protocol] = @old_default_url_options[:protocol] end end end end end module ActionMailer def self.included(am) am.send(:include, ::ActionController::UrlWriter) ::ActionController::UrlWriter.module_eval do default_url_options[:host] = 'localhost' default_url_options[:port] = 3000 default_url_options[:protocol] = 'http' end end end end ActionController::Base.send(:include, UrlWriterRetardaseInhibitor::ActionController) ActionMailer::Base.send(:include, UrlWriterRetardaseInhibitor::ActionMailer) (from url_writer_retardase_inhibitor.rb)
“Oh no!,” you exclaim, “Class Variables!! Get behind me, Satan!”.
Well, get over it. How do you think with_scope works? How do you think you can call a Finder like User.find or User.new wherever you feel like? It’s called Global Variables, man. Embrace it. I call this liberation theology.
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