Tldr
This gem uses both Mandrill API and ActionMailer to send email.
Setup
Install mandrill mailer gem
gem 'mandrill_mailer'
Add .env configurations
BASE_URL_FE=
DEFAULT_EMAIL_SENDER=
USE_MANDRILL_MAILER=
MANDRILL_SMTP_ADDRESS=
MANDRILL_SMTP_DOMAIN=
MANDRILL_SMTP_PASSWORD=
MANDRILL_SMTP_USERNAME=
MANDRILL_SMTP_PORT=
MANDRILL_SMTP_AUTO_TLS=
MANDRILL_SMTP_TLS=
MAILER_SMTP_ADDRESS=
MAILER_SMTP_DOMAIN=
MAILER_SMTP_PASSWORD=
MAILER_SMTP_USERNAME=
MAILER_SMTP_PORT=
MAILER_SMTP_AUTO_TLS=
MAILER_SMTP_TLS=
Add this to config/initializer/mailer.rb
ActionMailer::Base.delivery_method = :smtp
# change it to your helper class name
ActionMailer::Base.add_delivery_method :mandrill_mailer, MandrillMailer
# uncomment if neccessary
smtp_settings = {
address: ENV["USE_MANDRILL_MAILER"].to_i == 1 ? ENV['MANDRILL_SMTP_ADDRESS'] : ENV["MAILER_SMTP_ADDRESS"],
# authentication: ENV["USE_MANDRILL_MAILER"].to_i == 1 ? 'plain' : nil,
domain: ENV["USE_MANDRILL_MAILER"].to_i == 1 ? ENV['MANDRILL_SMTP_DOMAIN'] : ENV["MAILER_SMTP_DOMAIN"],
enable_starttls_auto: ENV["USE_MANDRILL_MAILER"].to_i == 1 ? true : false,
tls: ENV["USE_MANDRILL_MAILER"].to_i == 1 ? true : false,
# password: ENV["USE_MANDRILL_MAILER"].to_i == 1 ? ENV['MANDRILL_SMTP_PASSWORD'] : ENV["MAILER_SMTP_PASSWORD"],
port: ENV["USE_MANDRILL_MAILER"].to_i == 1 ? ENV['MANDRILL_SMTP_PORT'] : ENV["MAILER_SMTP_PORT"],
# user_name: ENV["USE_MANDRILL_MAILER"].to_i == 1 ? ENV['MANDRILL_SMTP_USERNAME'] : ENV["MAILER_SMTP_USERNAME"],
# openssl_verify_mode: "none",
}
if ENV["USE_MANDRILL_MAILER"].to_i == 1
smtp_settings[:authentication] = 'plain'
smtp_settings[:password] = ENV['MANDRILL_SMTP_PASSWORD']
smtp_settings[:user_name] = ENV['MANDRILL_SMTP_USERNAME']
end
ActionMailer::Base.smtp_settings = smtp_settings
ActionMailer::Base. = {
host: ENV["BASE_URL_FE"]
}
ActionMailer::Base.register_preview_interceptor(ActionMailer::InlinePreviewInterceptor)
# Don 't care if the mailer can't send.
ActionMailer::Base.raise_delivery_errors = true
ActionMailer::Base.perform_deliveries = true
ActionMailer::Base.perform_caching = false
MandrillMailer.configure do |config|
config.api_key = ENV["MANDRILL_SMTP_PASSWORD"]
config.deliver_later_queue_name :default
end
# How to Use
Mandrill Example
require 'dcidev_mailer/mandrill'
class MandrillMailer
class << self
def send_email(customer: nil, email_template: nil, attachments: nil, description: nil)
raise "invalid customer"if customer.nil?
raise "invalid template" if email_template.nil?
begin
response = ::DcidevMailer::Mandrill.send_email(
subject: email_template.subject,
html_body: MailerHelper.format_wording(email_template.wording, customer),
header_url: email_template.header.try(:url),
footer_url: email_template.footer.try(:url),
# to: customer.email / can also accept string
to: [{name: "Punto Damar P", type: "to", email: "[email protected]"}],
cc: nil, # can be a string / array
bcc: nil, # can be a string / array
from: ENV['DEFAULT_EMAIL_SENDER'],
from_name: ENV['DEFAULT_EMAIL_SENDER_NAME'],
attachments: attachments,
email_template_path: "mail/blast.html.erb"
# specify template file location
)
rescue => e
error_message = "[SEND EMAIL] " + e.try(:to_s)
ensure
EmailHistory.create(application: customer.application, template: email_template, status: response[0]["status"] == "sent" ? :sent : :failed, mail_provider_id: response[0]["_id"], form_cetak_attachment: attachments.present?, error_message: response[0]["reject_reason"]) if response.present?
ApplicationHistory.log(description: error_message || description, application: customer.application)
end
end
end
Mandrill Template Example
require 'dcidev_mailer/mandrill_template'
class MandrillMailer
class << self
def send_email(customer: nil, email_template: nil, attachments: nil, description: nil)
raise "invalid customer"if customer.nil?
raise "invalid template" if email_template.nil?
begin
response = ::DcidevMailer::MandrillTemplate.send_email(
subject: email_template.subject,
header_url: email_template.header.try(:url),
footer_url: email_template.footer.try(:url),
template_name: 'customer blast',
to: [{name: "Punto Damar P", type: "to", email: "[email protected]"}],
vars: {customer_name: "Punto Damar P", bank_name: "Bang Jago"}, # template variable name configurable from mandrill dashboard
cc: nil, # can be a string / array
bcc: nil, # can be a string / array
from: ENV['DEFAULT_EMAIL_SENDER'],
from_name: ENV['DEFAULT_EMAIL_SENDER_NAME'],
attachments: attachments,
)
rescue => e
error_message = "[SEND EMAIL] " + e.try(:to_s)
ensure
EmailHistory.create(application: customer.application, template: email_template, status: response[0]["status"] == "sent" ? :sent : :failed, mail_provider_id: response[0]["_id"], form_cetak_attachment: attachments.present? , error_message : response[0]["reject_reason"]) if response.present?
ApplicationHistory.log(description: error_message || description, application: customer.application)
end
end
end
Action Mailer Example
require 'dcidev_mailer/rails_mailer'
class MortgageMailer
class << self
def email(customer: nil, template: nil, file_attachments: nil, description: nil)
begin
raise "invalid customer" if customer.nil?
raise "invalid template" if template.nil?
raise "email is empty" if customer.email.nil?
wording, _ = DcidevMailer.format_image_from_html(template.wording)
wording = MailerHelper.format_wording(wording,customer)
DcidevMailer::RailsMailer.email(
html_body: wording,
header_url: template.header.try(:url),
footer_url: template..try(:url),
file_attachments: ,
to: "#{customer.name} <#{customer.email}>",
cc: nil, # can be a string / array
bcc: ["John Doe <[email protected]>", "Michael <[email protected]>"], # can be a string / array
subject: template.subject,
from: "#{ENV['DEFAULT_EMAIL_SENDER_NAME']} <#{ENV['DEFAULT_EMAIL_SENDER']}>",
template_path: "mail/blast.html.erb" # specify template file location
).deliver_now!
rescue => e
= "[SEND EMAIL] " + e.try(:to_s)
ensure
EmailHistory.create(status: .present? ? :failed : :sent, error_message: , application: customer.application, template: template, form_cetak_attachment: .present?)
ApplicationHistory.log(description: || description, application: customer.application)
end
end
end
end
Sending Attachments
The attachment is an array of hashes containing attachment file and filename
= [{file: DcidevUtility.download_to_file(self.ktp.url), filename: self.reference_number}]
Inline Images
MandrillMailer supports sending images in the html body. As for RailsMailer, it currently only supports header & footer image. Feel free to contact me if you need such feature.
Since gmail do not support link-based image, you have to format the images as inline attachments and use CID (Content-ID) to display each of them. The gem automatically takes care of the programming. You only have to specify a valid link as the parameter.
The example to set the image in the template is shown below. This method works for both RailsMailer and MandrillMailer so you only need to code once.
<%
header = attachments['header'].try(:url) || header
footer = attachments['footer'].try(:url) || footer
%>
<% if header.present? %>
<div id="header-section-img">
<img
src="<%= header %>"
alt="Header Image"
style="border-radius: 10px"
width="100%"
/>
</div>
<% end %>
Development tips for custom SMTP server
Some clients dont allow our server to access their SMTP server. To avoid blind coding, you can develop using google SMTP server to make sure that your program woks perfectly. Refer to https://dev.to/morinoko/sending-emails-in-rails-with-action-mailer-and-gmail-35g4 for the tutorial.
Helpers
# convert all image URL in <img src="url"> to <img src="cid:xxxx">
DcidevMailer::format_image_from_html(html)
# format array of attachment files
DcidevMailer::()
# format email header & footer url to be embedded to html body
# refer to class DcidevMailer::Mandrill or DcidevMailer::Rails for more details about the usage
DcidevMailer::(header_url: "", footer_url: "", locals: {}, images: {})