BlueEye's original creator, Ben Lamb, was searching for a way to build a Sinatra skeleton similar to running how Rails creates applications using rails new APP-NAME. Corneal was the closest thing he could find and this gem is based largely off of it. Corneal does for Sinatra what running Rails' generators would do for a Ruby on Rails application. Over time, Brian's focus would shift to the Elixir language and Corneal development would languish. Ben Lamb got the inspiration to continue development and forked Corneal with a new name blue-eyes as a shout-out to Sinatra. Ben's contributions kept the gem operational with Ruby 2.

Fast-forward to 2025, Stan Carver II maintains the BlueEyes gem to compliment to his ongoing work on Frankie, the essential Sinatra boilerplate repository. His open-source contributions allows BlueEyes to fully support Ruby 3 and newer versions of Sinatra, Rails, and other gems. BlueEyes now generates full test suites tools to aid with rapid development of microsites and APIs.

gem install blue-eyes gem, run blue-eyes new APP-NAME, cd into your app's folder, then run bundle install. You're all set to start developing your Sinatra application. You can start up your server with rackup and verify everything is working. It is as simple as that!

BlueEyes creates a file structure similar to Ruby on Rails.

├── app
│   ├── controllers
│   │   └── application_controller.rb
│   ├── models
│   └── views
│       ├── layout.erb
│       └── welcome.erb
├── bin
│   └── dev
├── config
│   ├── initializers
│   │   ├── database.rb
│   │   └── redis.rb
│   └── environment.rb
├── db
│   └── migrate
├── lib
├── public
│   ├── images
│   ├── javascripts
│   └── stylesheets
│       └── main.css
├─── spec
│   ├── application_controller_spec.rb
│   └── spec_helper.rb
├── .rubocop_todo.yml
├── .rubocop.yml
├── .simplecov
├── config.ru
├── Gemfile
├── Gemfile.lock
├── Guardfile
├── Procfile
├── Procfile.dev
├── Rakefile
└── README		

BlueEyes should be installed in the global gem space rather than in a Gemfile.

gem install blue-eyes

blue-eyes -v              # Show BlueEyes version number
blue-eyes help [COMMAND]  # Describe available commands or one specific command
blue-eyes new APP-NAME    # Creates a new Sinatra application
blue-eyes model NAME      # Generate a model
blue-eyes controller NAME # Generate a controller
blue-eyes scaffold NAME   # Generate a model with its associated views and controllers

The controller generator also have an optional views flag --no-views to create controllers without views.

To generate your app:

blue-eyes new APP-NAME

Once BlueEyes has generated your app, run bundle install from your app's directory:

cd APP-NAME
bundle install

You can then start your server with the bundled rackup gem and visit http://localhost:9292 to verify your running web application.

bundle exec rackup

In similar Rails' fashion, you can generate a model and migration file:

blue-eyes model NAME

You can also generate an entire Rails-style MVC structure complete with a migration file:

blue-eyes scaffold NAME

The resulting structure will look like this:

└─ app
│  ├── controllers
│  │   ├── application_controller.rb
│  ├── models
│  │   └── model_name.rb
│  └── views
│      └── model_names
│          ├──index.html.erb
│          ├──show.html.erb
│          ├──new.html.erb
│          └──edit.html.erb
└── db/migrate
    └── timestamp_create_models.rb

You can also add your model attributes when you generate the scaffold structure and have them added to your migration file:

blue-eyes [model/scaffold] NAME name:string age:integer

class CreateUsers < ActiveRecord::Migration
  def change
    create_table :users do |t|
      t.string :name
      t.age :integer

      t.timestamps null: false
    end
  end
end

After creating a model or scaffold, you will need to run bundle exec rake db:migrate to update the database table.

You can run the test suite with bundle exec rspec to ensure your app is still operational:

Run options: include {focus: true}

All examples were filtered out; ignoring {focus: true}
....

Finished in 0.04369 seconds (files took 2.31 seconds to load)
4 examples, 0 failures, 0 pending

You can run bundle exec rubocop -A to automatically fix any linting issues. It can uncover bugs too!

You can run bundle exec guard for continuous testing and linting while developing your application.

Better yet, you can execute bin/dev to start your server, run your tests, and lint your code all at once. Any changes to your application will automatically reload your application, run your tests, and/or lint your code. 💙 Developer happiness acheived. 💙

CONTRIBUTING LICENSE TODO

©2025 Stan Carver II