# Follow-Up: Receiving Inbound Email and Creating Data in Rail

**URL:** <https://www.ruby-forum.com/t/follow-up-receiving-inbound-email-and-creating-data-in-rail/91329>\
**Category:** Rails\
**Created:** [April 6, 2007, 9:20pm UTC](https://www.ruby-forum.com/t/follow-up-receiving-inbound-email-and-creating-data-in-rail/91329 "2007-04-06T21:20:18Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![nathandelane](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/df705f/32.png) [@nathandelane](https://www.ruby-forum.com/u/nathandelane)\
**Post date:** [April 6, 2007, 9:20pm UTC](https://www.ruby-forum.com/t/follow-up-receiving-inbound-email-and-creating-data-in-rail/91329/1 "2007-04-06T21:20:18Z")

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I just wanted to post back to the group with my potential solution for  
receiving inbound email and creating data in my Rails application,  
including  
attached images. Hope this will be helpful for others. Of course,  
suggestions for improving my ideas is always welcome.

Thanks to everyone who took the time to post helpful responses to my  
original (multiple) inquiries.

Nathan

Overall Requirement

I needed a feature in my Rails application that would receive inbound  
emails  
(from a Palm Treo 680, in particular) including an attached image. I  
wanted  
to use this data to create an entry in a product database for an online  
shopping web site. This requirement supports a small business owner who  
travels, finds products to buy and resell, and wanted immediate (easy)  
posting of available items on the site using a mobile device.

Design:

I decided to use a plain text email, with a defined format…

- Subject = product title
- 1st line = product description
- 2nd line = product price
- 3rd line = product cost (for accounting application sync)
- 4th line = product quantity
- Attachment = product image

I created a “mailer” model inheriting from ActionMailer. The mailer  
model  
had two important methods (among others). The first was the “check”  
method  
which will use Net::IMAP to poll the INBOX folder for new mail. The  
check  
method would then call the “receive” method which will take an  
individual  
mail, create a product, and create an associated image in the database.  
Finally, there is a “delete” method which removes the processed mail  
from  
the inbox.

PROBLEM: I could not get IMAP to allow deletion of the old messages. I  
actually had to use POP3 to do it. Something wacky here that may just  
be my  
ignorance on this topic.

One of the bigger questions for me was how to periodically process the  
mail. There were several possibilities here and may well be others that  
I  
didn’t know about or consider. Here are a couple of the more popular  
ones…

- Use a server script to periodically “push” the mail into the Rails  
app using cron
- Use BackgroundRb to create a Rails background process for reading  
the mail periodically

However, I chose something a little simpler and possibly weird. I used  
the  
application controller to call the check mail function once per  
user/browser  
session. So inside the application.rb I have a before filter that calls  
a  
method. The method checks for a session variable that indicates whether  
mail has been checked yet or not. If not, it calls the model method for  
doing so. I don’t know the complete implications or trade-offs here, so  
this is an area where I would be happy to get input from Ruby/Rails  
experts. Given the low usage of the site and small number of products  
being  
entered, I chose to use this given that the only downside seemed to be a  
small wait (1-2 seconds) on the initial site load for the mail to be  
checked  
and the parts/images loaded.

Development/Code:

class Mailer \< ActionMailer::Base  
.  
.  
.  
def self.check\_mail  
begin  
imap = Net::IMAP.new(‘mail.\*\*\*.com’)  
if RAILS\_ENV == “production”  
imap.authenticate(‘LOGIN’, ‘prduser’, ‘prdpasswd’)  
else  
imap.authenticate(‘LOGIN’, ‘devuser’, ‘devpasswd’)  
end  
imap.examine(‘INBOX’)  
imap.search([‘FROM’, ‘validuser@\*\*\*.com’]).each do |message\_id|  
msg = imap.fetch(message\_id,‘RFC822’)[0].attr[‘RFC822’]  
envelope = imap.fetch(message\_id,  
“ENVELOPE”)[0].attr[“ENVELOPE”]  
Mailer.receive(msg)  
end  
imap.logout  
return true  
rescue  
RAILS\_DEFAULT\_LOGGER.error("Mailer Import Error: " + $!)  
return false  
end  
end

def receive(email) return unless email.has\_attachments?  
emailbody = email.body.to\_s.gsub(/\r/, ’ ')  
part = Part.new  
part.description = email.subject  
part.notes = emailbody.split(/\n/)[0]  
part.sellprice = emailbody.split(/\n/)[1].to\_f  
part.lastcost = emailbody.split(/\n/)[2].to\_f  
part.onhand = emailbody.split(/\n/)[3].to\_i  
part.partsgroup\_id = 10280  
if part.save!  
email.attachments.each do |attachment|  
next unless attachment.original\_filename[-4…-1] == ‘.jpg’  
picture = Picture.new  
picture.name = email.subject  
picture.part\_id = part.id  
picture.imagedata = attachment.read  
picture.content\_type = ‘image/jpeg’  
picture.save!  
end  
end  
end

def self.delete\_mail  
if RAILS\_ENV ==“production”  
Net::POP3.delete\_all(‘mail.\*\*\*.com’, 110, ‘prduser’, ‘prdpasswd’)  
else  
Net::POP3.delete\_all(‘mail.\*\*\*.com’, 110, ‘devuser’, ‘devpasswd’)  
end  
rescue  
RAILS\_DEFAULT\_LOGGER.error("Mailer Import Error: " + $!)  
end  
end

class ApplicationController \< ActionController::Base  
before\_filter :env

def env  
if !session[:checked\_mail]  
if Mailer.check\_mail  
session[:checked\_mail] = true  
Mailer.delete\_mail  
end  
end  
end  
.  
.  
.  
end

Testing:

So far, this solution seems to work pretty well. I have not tested  
large  
numbers of emails or large numbers of concurrent users. This is only a  
potential solution and not one I would recommend for a larger site.  
Let’s  
have it…what do you think? How can this be improved?

---

<div class="post-metadata">

**Author:** ![nathandelane](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/df705f/32.png) [@nathandelane](https://www.ruby-forum.com/u/nathandelane)\
**Post date:** [April 7, 2007, 12:48am UTC](https://www.ruby-forum.com/t/follow-up-receiving-inbound-email-and-creating-data-in-rail/91329/2 "2007-04-07T00:48:37Z")

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Nathan L. wrote:

> Overall Requirement
> 
> model had two important methods (among others). The first was the  
> One of the bigger questions for me was how to periodically process the  
> used the application controller to call the check mail function once
> 
> ```
> imap.authenticate ('LOGIN', 'prduser', 'prdpasswd')
> return true
> part.notes = emailbody.split(/\n/)[0]
> picture.imagedata = attachment.read
> Net::POP3.delete_all('mail.***.com', 110, 'devuser', 'devpasswd')
> if !session[:checked_mail]
> 
> ```
> 
> Testing:
> 
> So far, this solution seems to work pretty well. I have not tested  
> large numbers of emails or large numbers of concurrent users. This is  
> only a potential solution and not one I would recommend for a larger  
> site. Let’s have it…what do you think? How can this be improved?  
> hmmm,

The biggest thing is as you said, checking the email on each session  
will not scale. In fact, the first request for each user will have to  
wait on the mail to fetched and parsed. cron or backgroundrb would be  
much better for that.

I think there should be a more rubyesque way for the emailbody.split  
lines but nothing comes to mind.

You should put the dev and production email passwords into the  
environment in the config folder along with the database password. Then  
just use the value set by the environment.

Sincerely,  
Jason

---

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**Author:** ![nathandelane](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/df705f/32.png) [@nathandelane](https://www.ruby-forum.com/u/nathandelane)\
**Post date:** [April 8, 2007, 12:27am UTC](https://www.ruby-forum.com/t/follow-up-receiving-inbound-email-and-creating-data-in-rail/91329/3 "2007-04-08T00:27:36Z")

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On Fri, 2007-04-06 at 18:47 -0400, Jason E. wrote:

> environment in the config folder along with the database password. Then  
> just use the value set by the environment.
> 
> Sincerely,  
> Jason

Jason,

Great points. I will move the settings to the config folder and try to  
find another way to process the email body.

I am considering the other two background email processing options. I  
do have another idea to improve the current call to the Mailer model.  
Not sure how feasible it is for production, but it seems to be working  
in development ok.

I was wondering about using a process fork to call the email  
check/receive. Take a look at this code that would reside in the  
application controller…

```
if !session[:checked_mail]
  Process.detach fork {
    if Mailer.check_mail
      session[:checked_mail] = true
    end
  }
end

```

Would it alleviate the performance and/or scaling issues? Will this  
cause problems?

Nathan

---

<div class="post-metadata">

**Author:** ![nathandelane](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/df705f/32.png) [@nathandelane](https://www.ruby-forum.com/u/nathandelane)\
**Post date:** [April 11, 2007, 9:03pm UTC](https://www.ruby-forum.com/t/follow-up-receiving-inbound-email-and-creating-data-in-rail/91329/4 "2007-04-11T21:03:37Z")

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> Backgroundrbis here :[http://backgroundrb.rubyforge.org/](http://backgroundrb.rubyforge.org/)
> 
> Note that it can integrate with rails easily 😉 as long as you work on  
> a unix machine.

The latest Backgroundrb (0.2.1) runs fine on cygwin (=unix-like env  
for windows)

/Nils

---

<div class="post-metadata">

**Author:** ![nathandelane](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/df705f/32.png) [@nathandelane](https://www.ruby-forum.com/u/nathandelane)\
**Post date:** [April 11, 2007, 8:34pm UTC](https://www.ruby-forum.com/t/follow-up-receiving-inbound-email-and-creating-data-in-rail/91329/5 "2007-04-11T20:34:00Z")

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Nathan L. wrote:

> On Fri, 2007-04-06 at 18:47 -0400, Jason E. wrote:
> 
> > environment in the config folder along with the database password. Then  
> > just use the value set by the environment.
> > 
> > Sincerely,  
> > Jason
> 
> Jason,
> 
> Great points. I will move the settings to the config folder and try to  
> find another way to process the email body.
> 
> I am considering the other two background email processing options. I  
> do have another idea to improve the current call to the Mailer model.  
> Not sure how feasible it is for production, but it seems to be working  
> in development ok.
> 
> I was wondering about using a process fork to call the email  
> check/receive. Take a look at this code that would reside in the  
> application controller…
> 
> ```
> if !session[:checked_mail]
> Process.detach fork {
> if Mailer.check_mail
> session[:checked_mail] = true
> end
> }
> end
> 
> ```
> 
> Would it alleviate the performance and/or scaling issues? Will this  
> cause problems?
> 
> Nathan

Hi nathan,

May be you need to look to check backgroundrb and create a scheduled  
worker that will check for email every x minutes … or hours …

I will have a try soon as I want my users to be able to upload photos by  
email 😉

Backgroundrb is here : [http://backgroundrb.rubyforge.org/](http://backgroundrb.rubyforge.org/)

Note that it can integrate with rails easily 😉 as long as you work on  
a unix machine.

Happy rails coding everyone !