Rails 5.0 example application using Active Job for background processing. The application lets a visitor join a MailChimp-hosted mailing list.
Use this example application as a starter app for your own web applications. For a complete explanation of the code, see the tutorial:
You can build this application in only a few minutes using the Rails Composer tool, choosing either a Bootstrap or Foundation front-end framework, as well as many other options, such as Haml or Slim.
From the RailsApps Project
The RailsApps open source project offers starter applications and tutorials for Rails developers. Generate the applications with the Rails Composer tool.
All the code is explained in the Capstone Rails Tutorials. You can purchase the Capstone Rails Tutorials to support the project.
If You Are New to Rails
What Is Implemented — and What Is Not
The application can be used for a simple web application that encourages a visitor to sign up for a mailing list. Asking for an email address gives the site owner a way to stay in touch with visitors. The application uses Active Job to process a task in the background, for a faster and more responsive user experience. Active Job, introduced in Rails 4.2, is useful for any application that connects to an external server.
The tutorial provides additional code, showing how to:
- use landing pages to segment a mailing list
- record referrer data to improve marketing efforts
These additional features are not related to background processing but they are useful if you are signing up visitors for a mailing list.
The application requires a database. The example application uses SQLite with Rails ActiveRecord. You can easily substitute PostgreSQL, MySQL, or other databases.
The example application (here in the GitHub repository) integrates Bootstrap for a navigation bar and flash messages. The rails_layout gem is included so you can switch to the Foundation front-end framework.
Similar Examples and Tutorials
This is one in a series of Rails example apps and tutorials from the RailsApps Project. See a list of additional Rails examples, tutorials, and starter apps. Related example applications may be useful:
- Learn Rails companion to the book Learn Ruby on Rails
- Foundation and Rails shows how to integrate Foundation
- Bootstrap and Rails shows to integrate Bootstrap
- OmniAuth and Rails uses OmniAuth for authentication
- Devise and Rails uses Devise for authentication
- Role-Based Authorization using simple roles
- Pundit and Rails uses Pundit for authorization
Accounts You Will Need
You’ll need a MailChimp account.
When visitors submit an email address, the application will add them to a MailChimp list. To access MailChimp, we’ll need a MailChimp API key. “Log in to MailChimp”https://admin.mailchimp.com/ to get your API key. Click your name at the top of the navigation menu, then click “Account”. Click “Extras,” then “API keys.” You have to generate an API key; MailChimp doesn’t create one automatically.
You’ll also need to create a MailChimp mailing list. The MailChimp “Lists” page has a button for “Create List.” The list name and other details are up to you. We’ll need the MAILCHIMP_LIST_ID for the mailing list you’ve created. To find the list ID, on the MailChimp “Lists” page, click the “down arrow” for a menu and click “Settings.” At the bottom of the “List Settings” page, you’ll find the unique ID for the mailing list.
With MailChimp, you can send a welcome message automatically when the visitor signs up for the mailing list. Use the welcome message to inform the visitor that they’ve successfully subscribed to the mailing list. It’s a bit difficult to find the MailChimp option to create a welcome message. Strangely, MailChimp considers a welcome message a “form.” Here’s how to find it. On the MailChimp “Lists” page, click the “down arrow” for a list and click “Signup forms.” Then click “General forms.” On the “Create Forms” page, there is a drop-down list of “Forms & Response Emails.” The gray box shows “Signup form.” Click the down arrow. Select the menu item named “Final ‘Welcome’ Email” and you’ll be able to create a welcome message.
We provide instructions to deploy the application to Heroku which provides Rails application hosting. It costs nothing to set up a Heroku account and deploy as many applications as you want. To deploy an app to Heroku, you must have a Heroku account. Visit Heroku to set up an account.
Before generating your application, you will need:
- The Ruby language – version 2.3.1
- The Rails gem – version 5.0
Getting the Application
You have several options for getting the code on your own machine. You can fork, clone, or generate.
If you’d like to add features (or bug fixes) to improve the example application, you can fork the GitHub repo and make pull requests. Your code contributions are welcome!
If you want to copy and customize the app with changes that are only useful for your own project, you can clone the GitHub repo. You’ll need to search-and-replace the project name throughout the application. You probably should generate the app instead (see below). To clone:
$ git clone git://github.com/RailsApps/rails-mailinglist-activejob.git
If you want to use the project as a starter application, use the Rails Composer tool to generate a new version of the example app. You’ll be able to give it your own project name when you generate the app. Generating the application gives you additional options.
To build the example application, Rails 5.0 must be installed in your development environment. Run the command:
$ rails new rails-mailinglist-activejob -m https://raw.github.com/RailsApps/rails-composer/master/composer.rb
$ character indicates a shell prompt; don’t include it when you run the command.
This creates a new Rails app named
rails-mailinglist-activejob on your computer. You can use a different name if you wish.
You’ll see a prompt:
option Build a starter application? 1) Build a RailsApps example application 2) Contributed applications 3) Custom application
Enter “1” to select Build a RailsApps example application. You’ll see a prompt:
option Choose a starter application. 1) learn-rails 2) rails-bootstrap 3) rails-foundation 4) rails-mailinglist-activejob 5) rails-omniauth 6) rails-devise 7) rails-devise-roles 8) rails-devise-pundit 9) rails-signup-download 10) rails-stripe-checkout
Choose rails-mailinglist-activejob. The Rails Composer tool may give you other options (other applications may have been added since these notes were written).
The application generator template will ask you for additional preferences:
option Web server for development? 1) WEBrick (default) 2) Thin 3) Unicorn 4) Puma 5) Phusion Passenger (Apache/Nginx) 6) Phusion Passenger (Standalone) option Web server for production? 1) Same as development 2) Thin 3) Unicorn 4) Puma 5) Phusion Passenger (Apache/Nginx) 6) Phusion Passenger (Standalone) option Database used in development? 1) SQLite 2) PostgreSQL 3) MySQL option Template engine? 1) ERB 2) Haml 3) Slim option Test framework? 1) None 2) RSpec with Capybara option Continuous testing? 1) None 2) Guard option Front-end framework? 1) None 2) Bootstrap 3.2 3) Bootstrap 2.3 4) Zurb Foundation 5.4 5) Zurb Foundation 4.0 6) Simple CSS option Add support for sending email? 1) None 2) Gmail 3) SMTP 4) SendGrid 5) Mandrill option Install page-view analytics? 1) None 2) Google Analytics 3) Segment.io option Prepare for deployment? 1) no 2) Heroku 3) Capistrano option Set a robots.txt file to ban spiders? (y/n) n option Create a GitHub repository? (y/n) n option Use or create a project-specific rvm gemset? (y/n) y
If you plan to deploy to Heroku, select Unicorn as your production webserver. Unicorn is recommended by Heroku.
Use SQLite for development on Mac or Linux, unless you already have PostgreSQL installed locally. Use PostgreSQL if you plan to deploy to Heroku. You can easily change the database later if you select SQLite to start.
The example application uses the default “ERB” Rails template engine. Optionally, you can use another template engine, such as Haml or Slim. See instructions for Haml and Rails.
If you are a beginner, select “None.”
The example in the GitHub repository was built with the Bootstrap 3 front-end framework. Use Zurb Foundation 5.5 if you like. Choosing either Bootstrap or Foundation will automatically install views with attractive styling.
The example application does not send email to users, so you do not need to add support for sending email.
Set a robots.txt file to ban spiders if you want to keep your new site out of Google search results.
If you choose to create a GitHub repository, the generator will prompt you for a GitHub username and password.
If you get an error “OpenSSL certificate verify failed” or “Gem::RemoteFetcher::FetchError: SSL_connect” see the article OpenSSL errors and Rails.
Edit the README
If you’re storing the app in a GitHub repository, please edit the README files to add a description of the app and your contact info. If you don’t change the README, people will think I am the author of your version of the application.
See the article Installing Rails to make sure your development environment is prepared properly.
I recommend using RVM, the Ruby Version Manager, to create a project-specific gemset for the application. If you generate the application with the Rails Composer tool, you can create a project-specific gemset.
Here are the gems used by the application:
- gibbon – API wrapper for MailChimp
- high_voltage – shortcut for adding static pages like “About”
- simple_form – helpers for simplified forms
- sucker_punch – queuing for background jobs
These gems make development easier:
Your choice of front-end framework:
Install the Required Gems
If you used the Rails Composer tool to generate the example app, the application template script has already run the
bundle install command.
If not, you should run the
bundle install command to install the required gems on your computer:
$ bundle install
You can check which gems are installed on your computer with:
$ gem list
Keep in mind that you have installed these gems locally. When you deploy the app to another server, the same gems (and versions) must be available.
If you generate the application using the Rails Composer tool, you have the option to install either Bootstrap or Foundation.
Changing the Front-end Framework
The version of the application in the repository includes Bootstrap. If you wish to install Foundation instead, use the rails_layout gem to generate new files. First add a gem to the Gemfile:
Use Bundler to install the gem:
$ bundle install
To create layout files for use with Zurb Foundation 5.5:
$ rails generate layout:install foundation5
To consolidate configuration settings in a single location, we store credentials in the config/secrets.yml file. To keep your credentials private, use Unix environment variables to set your credentials. See the article Rails Environment Variables for more information.
Add your credentials to the file config/secrets.yml:
# Make sure the secrets in this file are kept private # if you're sharing your code publicly. development: domain_name: example.com mailchimp_api_key: <%= ENV["MAILCHIMP_API_KEY"] %> mailchimp_list_id: <%= ENV["MAILCHIMP_LIST_ID"] %> secret_key_base: some_long_string test: secret_key_base: some_long_string # Do not keep production secrets in the repository, # instead read values from the environment. production: domain_name: <%= ENV["DOMAIN_NAME"] %> mailchimp_api_key: <%= ENV["MAILCHIMP_API_KEY"] %> mailchimp_list_id: <%= ENV["MAILCHIMP_LIST_ID"] %> secret_key_base: <%= ENV["SECRET_KEY_BASE"] %>
All configuration values in the config/secrets.yml file are available anywhere in the application as variables. For example,
Rails.application.secrets.domain_name will return the string
If you don’t want to use Unix environment variables, you can set each value directly in the config/secrets.yml file. The file must be in your git repository when you deploy to Heroku. However, you shouldn’t save the file to a public GitHub repository where other people can see your credentials.
Database Seed File
The db/seeds.rb file is not needed in this application.
Set the Database
If you’ve used the Rails Composer tool to generate the application, the database is already set up with
If you’ve cloned the repo, prepare the database and add the default user to the database by running the command:
$ rails db:migrate
rails db:reset if you want to empty and reseed the database.
Change your Application’s Secret Token
If you’ve used the Rails Composer tool to generate the application, the application’s secret token will be unique, just as with any Rails application generated with the
rails new command.
However, if you’ve cloned the application directly from GitHub, it is crucial that you change the application’s secret token before deploying your application in production mode. Otherwise, people could change their session information, and potentially access your site without permission. Your secret token should be at least 30 characters long and completely random.
Get a unique secret token:
Edit the config/secrets.yml file to change the secret token.
Test the App
You can check that your application runs properly by entering the command:
$ rails server
To see your application in action, open a browser window and navigate to http://localhost:3000/.
You’ll see a home page with a sign-up form.
Enter your email address and click the “sign up” button. You should see the page redisplay with an acknowledgment message. Try entering an invalid email address such as “me@foo@”, or click the submit button without entering an email address, and you should see an error message.
You can log in to MailChimp and check your list of subscribers to see if the new email address was added successfully.
Stop the server with Control-C. If you test the app by starting the web server and then leave the server running while you install new gems, you’ll have to restart the server to see any changes. The same is true for changes to configuration files in the config folder. This can be confusing to new Rails developers because you can change files in the app folders without restarting the server. Stop the server each time after testing and you will avoid this issue.
RSpec Test Suite
The application contains a suite of RSpec tests. To run:
Deploy to Heroku
Heroku provides low cost, easily configured Rails application hosting.
You can deploy from the command line.
$ git push origin master
If you’ve set configuration values in the config/secrets.yml file, you’ll need to set them as Heroku environment variables. You can set Heroku environment variables directly with
heroku config:add. For example:
$ heroku config:add MAILCHIMP_API_KEY='a6v34ggf23c123098765fcc6c996c540-us2' MAILCHIMP_LIST_ID='4x8bfgb034'
Complete Heroku deployment with:
$ git push heroku master
See the Tutorial for Rails on Heroku for details.
Problems? Check the issues.
Please create a GitHub issue if you identify any problems or have suggestions for improvements.
Where to Get Help
Your best source for help with problems is Stack Overflow. Your issue may have been encountered and addressed by others.
Use the tag “railsapps” on Stack Overflow for extra attention.
If you make improvements to this application, please share with others.
Send the author a message, create an issue, or fork the project and submit a pull request.
If you add functionality to this application, create an alternative implementation, or build an application that is similar, please contact me and I’ll add a note to the README so that others can find your work.
Daniel Kehoe implemented the application and wrote the tutorial.
Is the app useful to you? Follow the project on Twitter: @rails_apps
and tweet some praise. I’d love to know you were helped out by what I’ve put together.
Copyright ©2014-16 Daniel Kehoe