Please follow the below steps to implement an
actionmailer in your app, create a rake task to call the mailer function and
schedule that particular task to run on a specific time.
1. To
Implement action mailer in rails~3:
Action mailer feature of rails allows to send emails. A mailer model and a view is required for the same.
In this tutorial, we would send the email using gmail service.
In this tutorial, we would send the email using gmail service.
Step 1: Create a demo
project.
rails new mail_project
Step 2: Create a User model.
rails
generate scaffold User name:string email:string
Step 3: Create a mailer model
rails
generate mailer UserMailer
create
app/mailers/user_mailer.rb
invoke erb create
app/views/user_mailer invoke test_unit
create
test/functional/user_mailer_test.rb
Step 4: Now, we need to
configure the SMTP mail settings in development.rb.
in
config\environments\development.rb
config.action_mailer.default_url_options = { :host =>
'localhost:3000.com' }
config.action_mailer.smtp_settings = {
:enable_starttls_auto => true,
:address
=> 'smtp.gmail.com',
:port
=> 587, # default port
for gmail.
:domain
=> 'your.domain.com',
:authentication => :login,
:content_type => "text/html",
:user_name
=> 'youremail@gmail.com',
:password
=> 'password'
}
Note: To deploy the
app on heroku, edit the settings in production.rb
Step 5: Edit the mailer and
create your mail method.
in app/mailers/user_mailer.rb , lets define a method
demo_mail
def demo_mail(user)
mail(:from => "Testmail@demo.com",
:to => user.email
:subject =>
"Greet User")
end
Note: To add pictures as
inline attachment/logo in rails 3, use as:
attachments.inline['rails.png']=File.read('app/assets/images/rails.png')
Step 6: Create a view template
to render the view, create the view with the same method name which we used in
our user_mailer.rb.
i.e views/user_mailer/demo_mail.html.erb
<!DOCTYPE
html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html
lang="en">
<head>
<meta
http-equiv="Content-Type" content="text/html;
charset=utf-8">
<style
type="text/css" media="screen" class =
"content">
h3 {
color: #f00; }
ul {
list-style: none; }
</style>
</head>
<body>
<strong><p class="text-warning">Dear <%= @user
%>,</p></strong>
<p
class="text-success">Hello, How are you ?</p>
<%=
image_tag attachments['rails.png'].url % >
</body>
</html>
Note : We have use
attachments.url in image_tag to display the inline attachment.
Step 7: Add a line to call the
method demo_mail of UserMailer.
- this could be done from a task
or from some method of User controller.
UserMailer.demo_mail(user).deliver!
Points to ponder:
1. While uploading your app on heroku, make sure that you have
done smtp mail setting in file production.rb
2. Inline attachment might be block from your office network. So
you can check them on gmail network.
3. Apart from that there might be few more problem on restricted
network.
2. How to
Create a rake task:
Step 1: Introduction to rake
- rake is a task which is created at /lib/tasks with .rake extension. Doing this, rails picks
it up automatically and make it available to you.
ex: demo.rake
- you can see your task listed by doing rake -T
- to run your task:
rake demo
Step 2: Writing a task on mailer created above
in
lib/tasks/demo.rake
namespace :demo do
desc "This is to send an email to
users"
task(:mail_users => :environment)
do
UserMailer.demo_mail(user).deliver!
# as we saw in Step7 above
end
end
Similarly,
many tasks can be created in this file and they all would be listed with
description.
Step 3: To
run/schedule task
this task can be
run as rake demo:mail_users
or
else we can schedule our task to run later.(Covered in section 3 of this blog)
3. How to schedule a rake
task:
To schedule a task demo of 'rufus-scheduler' is done here.
Otherwise there are so many ways to schedule a task. ex clockwork
and so many.
Step 1:
Introduction to rake
rufus-scheduler is a Ruby gem for scheduling
pieces of code (jobs). It understands running a job AT a certain time.
Step 2: Add Gem and install it
add gem 'rufus-scheduler' to your gemfile and run bundle install.
gem install rufus-scheduler
Step 3: Create a task_scheduler.rb file in /config/initializers
Schedule the task like:
require 'rubygems'
require 'rake'
require 'rufus/scheduler'
scheduler = Rufus::Scheduler.start_new
scheduler.every '15m' do
system 'bundle exec rake
demo:mail_users'
end
# this will trigger the mail_users task every 15
minutes.
Note: Similarly,
task can be schedule every hour, daily, weekly or monthly basis
