What would I need in a Rails 3 controller to process incoming emails and insert them into the database? - ruby

Question

I'm trying to set up my RoR 3 application to receive emails and then process those emails and insert them into the database.
In my application, I have a "jobs" controller. Users can create jobs. I also have a "comments" controller. Users can create comments on jobs.
Here is (part of) what I have in my comments controller:
def new
#job = Job.find(params[:job_id])
#comment = #job.comments.build
end
def create
#job = Job.find(params[:job_id])
#comment = #job.comments.build(params[:comment])
#comment.user_id = current_user.id
#comment.commenter = current_user.login
if #comment.save
redirect_to #job
else
render :action => "new"
end
end
When users add a comment, the admin receives an email.
When admins add a comment, users receive an email.
(This is already functioning.)
I'm using Cloudmailin to help me receive incoming mail. I've set up the Cloudmailin address to point to http://myapp.com/incoming_mails.
class IncomingMailsController < ApplicationController
require 'mail'
skip_before_filter :verify_authenticity_token
def create
another_comment = Comment.create(:title =>
params[:subject], :body => params[:plain])
render :text => 'success', :status => 200 #status of 404 rejects mail
end
end
Looking at the above comment controller, it looks like I'll need the job_id, current_user.id, and current_user.login.
Here's what I am having trouble sorting out: what goes in my "incoming_mails" controller? How can I make sure that when a user responds via email that the controller in "incoming_mails" is able to find the job_id and the current_user.id (or user_id) and then insert that information into the database?
I'm thinking that I'll need to grab the user's email address and then also have the job_id in the subject line...hmmm....
Does anyone have experience setting up incoming mail processing in Rails 3?

Answer 1

There's a few ways to do this. A common technique is to set the from/reply_to as a custom email address that allows you to do a lookup of the original object. Something like:
class Comment < ActiveRecord::Base
belongs_to :commentable
has_many :comments, :as => :commentable
before_validation :generate_token, :on => :create
validates :token, :presence => true, :uniqueness => true
attr_accessible :token
private
def generate_token
...
end
end
Email is sent with a from/reply_to address like [token]#msg.yoursite.com
(You can also use a comments+[token_or_id]#msg.yoursite.com if you'd like - see the :disposable param supplied by cloudmailin)
class IncomingMailsController < ApplicationController
def create
#comment = Comment.find_by_token(params[:to].split('#')[0])
#comment.comments.create(:body => params[:plain])
render :text => 'success', :status => 200
end
end
If you go the [token]#msg.yoursite.com then you have to setup your dns records properly as described here.
Another option is to store content in the headers of the email. Maybe your headers would look something like this:
X-YOURAPP-OBJECT-ID = 44
X-YOURAPP-OBJECT-TYPE = Job
X-YOURAPP-TARGET-ASSOC = comments
X-YOURAPP-TARGET-ATTR = body
Then your controller would look more like this:
class IncomingMailsController < ApplicationController
def create
headers = Mail::Header.new(params[:message])
object= headers[:x_yourapp_object_type].constantize.find(headers[:x_yourapp_object_id])
object.send(headers[:x_yourapp_target_assoc]).create(headers[:x_yourapp_target_attr] => params[:plain])
render :text => 'success', :status => 200
end
end
The advantage to doing it this way is that it's completely generic. You can have comments on jobs, comments on comments, or whatever. If you create another model that you also want to allow email reply on... just update the headers and you're set. The only issue is that you have to be careful of these headers being stripped out by mail clients. Take a look at this thread for more information about that.
I'm currently using the first technique and it's working very well. However, I'll be refactoring and trying the second technique at the end of this week.

Answer 2

I'm not sure this is a full answer but let me give it a quick shot and I can update it when I have a little more time.
Firstly I would start by having the job perhaps as part of the to address. Use comment+1#domain.com with 1 signifying that this is job number one. This part after the plus is called the is the disposable part in CloudMailin (params[:disposable]. The users email address can then be taken from the message body either using params[:from] or Mail.new(params[:message]).from (sometimes the from address given to the SMTP server is different to the one in the header)
Next you have the comment itself which can simply be the plain param.
This gives something like the following:
def create
#job = Job.find(params[:disposable])
if comment = #job.comments.create(:text => params[:plain], :commenter => User.find_by_email(params[:from])
render :text => 'Success', :status => 401
else
render :text => comment.errors.inspect, :status => 422, :content_type => 'text/plain'
end
I hope that helps. It's a bit rough but hopefully it gives the right idea.