How to pre-render a letter with action mailer in Rails? - ruby-on-rails

I need to send an exactly the same email to a bunch of users.
What I do now is:
emails.each { |em| MyMailer.letter(em).deliver_later }
The problem with that is that now for every single email, it will re-render the whole letter again and again (it's using the mjml to do this, so it's not fast). But I know that the email is exactly the same for all users, so can I sorta pre-render the template, so it only renders once?
Thanks!

Send it to multiple recipients using
mail(to: User.admin.pluck(:email), subject: "Hello Admins!")
This will send it to all the admins.
Check the doc for more info on this.

Related

Multiple recipients using Mandrill and Rails

I'm using ruby to send transactional emails via Mandrill.
As part of my product, I want to be able to send the same email to two recipients and have them see each other's email address.
(Like an introduction mail between two people).
So I filled he "to" field with both emails, and on my dashboard is seems that both are sent.
But unfortunately only one of the recipients receive the mail and the details of the second recipient is hidden.
In conclusion, I have two problems:
Only one recipient gets the mail
Hidden details of the second recipient.
I approached Mandrill support and this is what they replied:
If you'd like to enable this option globally for all of the messages you send, then you'll want to ensure that you have the
"Expose The List Of Recipients When Sending To Multiple Addresses"
option enabled in your Sending Defaults.
If, instead of making that change globally, you'd like to enable it
for individual messages, you'll want to use the
X-MC-PreserveRecipients (SMTP header), or the preserve_recipients (API
parameter), and set it to 'true'.
If you set this option to true, we'll expose the list of recipients to
each other as you would see happen when sending mail from a typical
email client program.
It worked!
If you want both recipients to be able to see each other, you can pass an array of e-mails in the to option.
If you do not want either of them to see each other, you can, in a loop over the users, send said e-mail.
If using ActionMailer it can be done like so:
mail(
to: ['person1#gmail.com', 'person2#gmail.com']
)
Or in a loop:
[user1, user2].each do |user|
UserMailer.some_email(user).deliver_now
end
mail(
to: user.email
)
Post your code, I have an idea of what your problem may be. Remember that a method in an ActionMailer class should only return mail() and must not be looped over inside of that method.
tldr: do everything unrelated to e-mail outside mailer, pass through necessary data as params to the method, end method with mail() call.

Converting comma separated string into array and few more things

I have a site which has two textboxes. The first one is for email and the second for a message. When someone enters their email and a message and presses submit it shows the submitted message on the home page. Unfortunately, it doesn't send email to anyone.
Now I want to make it possible to write multiple emails and when you press submit what it does is show each email/message separately and not one message with 3-4 emails(whatever emails you typed). The message is the same of course. Here is my _forms code http://pastie.org/private/wg5naoay5hxbvxmnp02sbg
I found out that first I have to separate string into arrays with .split(',') method.
I am not sure if I should do that in _forms file or model? Also after I do that split method, how to make it write out same message for each email separately and not one message with all those emails? If you need code let me know.
Thanks
Put this method in Helper
def emails
emails_array= email_string.split(',')
Mailer.send_mail(emails_array)
end
Put this in Mailer
Class Mailer
def send_email emails
emails.each do |email|
##your sending email logic for each email address
end
end
end

How to to mass email (500,000) using rails [duplicate]

I will be sending bulk emails from a Rails app and plan on using SendGrid. I am assuming that it is best to send a separate email to each recipient (as opposed to using BCC for all the recipients). If that is true, should I be using something like DelayedJob to queue the messages going over to SendGrid, or would it be safe to throw 500 messages at it all at once? Thanks!
500 messages really isn't that much to SendGrid. It's not even a blip on their radar. I worked for a company that sent out 2.7 million emails in a single month, and even then it's only just a blip.
With the SendGrid API's capabilities, you wouldn't be sending out 500 emails, you would send one email which has a specific SendGrid API header set. Why? Because have you ever tried to send 500 individual email messages and timed how long that takes? How about a single email? The single email's going to be quicker.
The SendGrid API has a Ruby example which is here:
https://sendgrid.com/docs/Integrate/Code_Examples/SMTP_API_Header_Examples/ruby.html.
That's quite long winded and messy, so let me simplify it for you. Basically, you set this in your email:
headers["X-SMTPAPI"] = { :to => array_of_recipients }.to_json
SendGrid will then parse this and then send that one email you sent it out to that array of recipients. I seem to recall that they ask you to limit this to about 1000 recipients per email, so it would be wise to split it up over multiple emails if you wanted that. That is when you would bring in something like the delayed_job or resque gems to deal with it.
Oh, and by the way you'll still need to specify a to address for this email just to make the Mail gem happy. We had info#ourcompany.com for that.
The SendGrid API will also support filters in their emails, so you can have placeholder strings such as {{ firstname }} and, assuming you send it through with the SMTPAPI header, it will do the "mail merge" on the email and customize them.
It would do you a great deal of good if you read the SendGrid API documentation. It's really useful and what they provide is super powerful.
I recommend using the sendgrid gem ( https://github.com/stephenb/sendgrid ) as it simplifies your calling code.
Here's an example rails 3 action mailer example:
class UserAnnouncementMailer < ActionMailer::Base
include SendGrid
default reply_to: "test#test.com", return_path: "test#test.com", from: "Test"
# bulk emailer
# params - opts a hash of
# emails: array of emails
#
def notice(opts={})
raise "email is nil" unless opts[:emails]
sendgrid_category :use_subject_lines
sendgrid_recipients opts[:emails]
name = "The Man"
to = "test#test.com"
from_name = "#{name} <theman#test.com>"
subject = "Important"
mail({from: from_name, to: to, subject: subject})
end
end
And the corresponding calling code. It's recommended to have the emails array to be < 1000 emails.
emails = ["alice#test.com", "bob#test.com"]
UserAnnouncementMailer.notice({:emails => emails}).deliver
See the sendgrid gem github readme for more details.
Delayed Job and SendGrid sound like the best option from what you say, but have you considered using one of the campaign mailers like Mailchimp instead? If you're sending out a lot of mails that are basically the same, they'll let you setup and campaign template and then fire a CSV of all the variables at it. They then effectively mail merge and fire them all out.
If however, you're only talking a few hundred you're on the right lines. SendGrid can easily handle the load, and you want to use Delayed Job so that you're not impacted by the performance of the SendGrid API should it not be favorable. Alternatively, look at Resque instead for sending mail as it may be more efficient.
I would imagine SendGrid can handle that kind of load. Most relay systems can. Also I would imagine if you sent the 500 in a CC API call, that their system would parse it and send them individually. I use Elastic Email (http://elasticemail.com) - and I know that this is how they handle it and it works great.
This is how I've done it in Rails 4
class NewsMailer < ApplicationMailer
include SendGrid
sendgrid_category :use_subject_lines
default from: 'My App! <support#myapp.com>'
def mass_mailer(news)
# Pass it in template
#news = news
# Custom method to get me an array of emails ['user1#email.com', 'user2#email.com',...]
array_of_emails = #news.recipients.pluck(:email)
# You can still use
# headers["X-SMTPAPI"] = { :to => array_of_emails }.to_json
sendgrid_recipients array_of_emails
mail to: 'this.will.be.ignored#ignore.me', subject: 'Weekly news'
end
end

Forward a mail using Tmail & ActionMailer::ARMailer

I'm writing a rake task to go through one of our mailboxes of incoming mail, using Tmail. For certain mails, i just want to forward them on to another address. I'm not sure what the best way to do that is though.
Our regular mails for the website are sent out using ARMailer: i call Mailer.deliver_ and the mail is generated from a template and put into our Email table, which in accessed by ARMailer which actually sends the mails out. So, the class definition of my Mailer class looks like this:
class Mailer < ActionMailer::ARMailer
#list of methods here, one per email type
end
So, what i want to do, is, in my script when i have a Tmail object representing the incoming mail, is to generate a new mail to stick into our mail queue which is basically the Tmail mail, forwarded onto a new address. I'm not sure what the best way to do that is. I could build up a new multipart mail copying the body, subject and from field from the recieved Tmail object, but that seems like it might be a bit clumsy, and that there should be a nicer way.
Can i do something like
newmail = Mailer.create_forward(my_tmail_object)
newmail.to = "forwardingaddress#domain.com"
newmail.deliver
??
Mailer/ARMailer doesn't have the create_forward method but it's something like that that i'm after. Any advice welcome! thanks

How to send emails with return-receipts in Ruby on Rails?

I have to send automatic emails with Return Receipt (aka "acknowledgement of receipt"), to have the confirmation that the receiver have actually received and read the email. The confirmation is a simple email sent to a specified address (the "Disposition-Notification-To" address, given in the email header).
Do you know if there is an easy way to do that with Rails (ActionMailer)? or with Ruby perhaps (TMail, Net/SMTP)?
Thanks in advance for your help.
You set your headers in your mailer def block like so:
headers['Return-Receipt-To'] = 'email#example.com'
headers['Disposition-Notification-To'] = 'email#example.com'
headers['X-Confirm-Reading-To'] = 'email#example.com'
Note that these trigger a dialogue in some, but not all email clients. Also, it is not a guarantee that the receiver actually has read and understood the email.

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