Lotus

A complete web framework for Ruby

Frameworks

Lotus combines small yet powerful frameworks:

Lotus::Utils - Ruby core extensions and class utilities
Lotus::Router - Rack compatible HTTP router for Ruby
Lotus::Validations - Validation mixin for Ruby objects
Lotus::Helpers - View helpers for Ruby applications
Lotus::Model - Persistence with entities, repositories and data mapper
Lotus::View - Presentation with a separation between views and templates
Lotus::Controller - Full featured, fast and testable actions for Rack

These components are designed to be used independently or together in a Lotus application. If you aren't familiar with them, please take time to go through their READMEs.

Status

Contact

Home page: http://lotusrb.org
Mailing List: http://lotusrb.org/mailing-list
API Doc: http://rdoc.info/gems/lotusrb
Bugs/Issues: https://github.com/lotus/lotus/issues
Support: http://stackoverflow.com/questions/tagged/lotus-ruby
Forum: https://discuss.lotusrb.org
Chat: http://chat.lotusrb.org

Rubies

Lotus supports Ruby (MRI) 2+

Installation

% gem install lotusrb

Usage

% lotus new bookshelf
% cd bookshelf && bundle
% bundle exec lotus server # visit http://localhost:2300

Architectures

Lotus is a modular web framework. It scales from single file HTTP endpoints to multiple applications in the same Ruby process.

Unlike other Ruby web frameworks, Lotus has flexible conventions for code structure. Developers can arrange the layout of their projects as they prefer. There is a suggested architecture that can be easily changed with a few settings.

Lotus encourages the use of Ruby namespaces. This is based on the experience of working on dozens of projects. By using Ruby namespaces, as your code grows it can be split with less effort. In other words, Lotus is providing gentle guidance for avoiding monolithic applications.

Lotus has a smart mechanism of duplication of its frameworks. It allows multiple copies of the framework and multiple applications to run in the same Ruby process. In other words, Lotus applications are ready to be split into smaller parts, but these parts can coexist in the same heap space.

All this adaptability can be helpful to bend the framework for your advanced requirements, but we recognize the need for guidance in standard architectures. For this reason Lotus is shipped with code generators.

Container architecture

TL;DR: Develop your application like a gem. Implement use cases in lib/. Use one or more Lotus applications in apps/.

This is the default architecture. Use it when you are ready to begin a new project.

The core of this architecture lives in lib/, where developers should build features independently from the delivery mechanism.

Imagine you are building a personal finance application, and you have a feature called "register expense." This functionality involves Money and Expense Ruby objects and the need for persisting data into a database. You can have those classes living in lib/pocket/money.rb and lib/pocket/expense.rb and use Lotus::Model to persist them.

It's based on a few simple concepts: use cases and applications. Use cases (features) should be implemented in lib/ with a combination of pure objects and the needed Ruby gems. One or more Lotus applications live in apps/. They are isolated from each other, and depend only on the code in lib/.

Each application should serve only one purpose: user-facing web application, administrative backend, JSON API, metrics dashboard, etc.

This architecture has important advantages:

Code reusability. You can consume a feature from the Web UI or from a HTTP API. Each can be a different Lotus application or simple Rack-based endpoints.
Decoupled components. The core of your application depends only on a few gems and it doesn't need to worry about the Web/HTTP/Console/Background jobs.
Applications are built like gems. This eases the process of packaging and sharing them among projects, without the need for many dependencies.
Avoid monoliths. Each Lotus application under apps/ is a candidate for later extraction into a separated microservice.

The last point is crucial. In the early days of a new project it is convenient to build and deploy all the code together. However, as time passes, it can become nearly impossible to extract sets of cohesive functionalities into separated deliverables. Lotus helps to plan those things ahead of time, but without the burden that is required by those choices, because it supports multiple applications natively.

Here's the name container: a Lotus "shell" that can run multiple micro applications in the same process.

% lotus new pocket --arch=container
% lotus new pocket # --arch=container is the default

Application architecture

upcoming

Micro architecture

upcoming

Conventions

Lotus expects controllers, actions and views to have a specific pattern (see Configuration for customizations)
All the commands must be run from the root of the project. If this requirement cannot be satisfied, please hardcode the path with Configuration#root.
The template name must reflect the name of the corresponding view: Bookshelf::Views::Dashboard::Index for dashboard/index.html.erb.
All static files are served by the internal Rack middleware stack.
The application expects to find static files under public/ (see Configuration#assets)
If the public folder doesn't exist, it doesn't serve static files.

Non-Conventions

The application structure can be organized according to developer needs.
No file-to-name convention: modules and classes can live in one or multiple files.
No autoloading paths. They must be explicitly configured.

Configuration

A Lotus application can be configured with a DSL that determines its behavior.

require 'lotus'

module Bookshelf
  class Application < Lotus::Application
    configure do
      ########################
      # BASIC CONFIGURATIONS #
      ########################

      # Determines the root of the application (optional)
      # Argument: String, Pathname, defaults to Dir.pwd
      #
      root 'path/to/root' # or __root__

      # The relative load paths where the application will recursively load the code (mandatory)
      # Argument: String, Array<String>, defaults to empty set
      #
      load_paths << [
        'controllers',
        'views'
      ]

      # Handle exceptions with HTTP statuses (true) or don't catch them (false)
      # Argument: boolean, defaults to true
      #
      handle_exceptions true

      #######################
      # HTTP CONFIGURATIONS #
      #######################

      # The route set (mandatory)
      # Argument: Proc with the routes definition
      #
      routes do
        get '/', to: 'home#index'
      end

      # The route set (mandatory) (alternative usage)
      # Argument: A relative path where to find the routes definition
      #
      routes 'config/routes'

      # URI scheme used by the routing system to generate absolute URLs (optional)
      # Argument: A string, default to "http"
      #
      scheme 'https'

      # URI host used by the routing system to generate absolute URLs (optional)
      # Argument: A string, default to "localhost"
      #
      host 'bookshelf.org'

      # URI port used by the routing system to generate absolute URLs (optional)
      # Argument: An object coercible to integer, default to 80 if the scheme is http and 443 if it's https
      # This SHOULD be configured only in case the application listens to that non standard ports
      #
      port 2323

      # Toggle cookies (optional)
      # Argument: A [`TrueClass`, `FalseClass`], default to `FalseClass`.
      #
      cookies true

      # Toggle sessions (optional)
      # Argument: Symbol the Rack session adapter
      #           A Hash with options
      #
      sessions :cookie, secret: ENV['SESSIONS_SECRET']

      # Default format for the requests that don't specify an HTTP_ACCEPT header (optional)
      # Argument: A symbol representation of a mime type, default to :html
      #
      default_format :json

      # Rack middleware configuration (optional)
      #
      middleware.use Rack::Protection

      # HTTP Body parsers (optional)
      # Parse non GET responses body for a specific mime type
      # Argument: Symbol, which represent the format of the mime type (only `:json` is supported)
      #           Object, the parser
      #
      body_parsers :json, MyXMLParser.new

      ###########################
      # DATABASE CONFIGURATIONS #
      ###########################

      # Configure a database adapter (optional)
      # Argument: A Hash with the settings
      #           type: Symbol, :file_system, :memory and :sql
      #           uri:  String, 'file:///db/bookshelf'
      #                         'memory://localhost/bookshelf'
      #                         'sqlite:memory:'
      #                         'sqlite://db/bookshelf.sqlite3'
      #                         'postgres://localhost/bookshelf'
      #                         'mysql://localhost/bookshelf'
      #
      adapter type: :file_system, uri: ENV['DATABASE_URL']

      # Configure a database mapping (optional)
      # Argument: Proc
      #
      mapping do
        collection :users do
          entity     User
          repository UserRepository

          attribute :id,   Integer
          attribute :name, String
        end
      end

      # Configure a database mapping (optional, alternative usage)
      # Argument: A relative path where to find the mapping definitions
      #
      mapping 'config/mapping'

      ############################
      # TEMPLATES CONFIGURATIONS #
      ############################

      # The layout to be used by all the views (optional)
      # Argument: A Symbol that indicates the name, default to nil
      #
      layout :application # Will look for Bookshelf::Views::ApplicationLayout

      # The relative path where to find the templates (optional)
      # Argument: A string with the relative path, default to the root of the app
      #
      templates 'templates'

      #########################
      # ASSETS CONFIGURATIONS #
      #########################

      # Specify sources for assets (optional)
      # Argument: String, Array<String>, defaults to 'public'
      #
      assets << [
        'public',
        'vendor/assets'
      ]

      # Enabling serving assets (optional)
      # Argument: boolean, defaults to false
      #
      serve_assets true

      ###########################
      # SECURITY CONFIGURATIONS #
      ###########################

      # Set a default value for X-Frame-Options HTTP header
      # Argument: String
      # Remove this line to disable this feature
      #
      security.x_frame_options "DENY"

      # Set a default value for Content-Security-Policy HTTP header
      # Argument: String
      # Remove this line to disable this feature
      #
      security.content_security_policy "default-src 'none'; script-src 'self'; connect-src 'self'; img-src 'self'; style-src 'self';"

      #############################
      # FRAMEWORKS CONFIGURATIONS #
      #############################

      # Low level configuration for Lotus::View (optional)
      # The given block will be yielded every time `Lotus::View` is included.
      # This is helpful to share logic between views
      # See the related documentation
      # Argument: Proc
      #
      view.prepare do
        include Lotus::Helpers # they will be included in all the views
      end

      # Low level configuration for Lotus::Controller (optional)
      # Argument: Proc
      controller.prepare do
        include Authentication # included by all the actions
        before :authenticate!   # run auth logic before each action
      end
    end

    ###############################
    # ENVIRONMENTS CONFIGURATIONS #
    ###############################

    configure :development do
      # override the general configuration only for the development environment
      handle_exceptions false
      serve_assets      true
    end

    configure :test do
      # override the general configuration only for the test environment
      host 'test.host'
    end
  end
end

Command line

Lotus provides a few command line utilities:

Server

It looks at the config.ru file in the root of the application, and starts the Rack server defined in your Gemfile (eg. puma, thin, unicorn). It defaults to WEBRick.

It supports code reloading feature by default, useful for development purposes.

% bundle exec lotus server

Generators

Action generator

It generates an action, a view, a template, a route and the relative unit tests.

% bundle exec lotus generate action web dashboard#index

The web argument is the name of the application under apps/. The dashboard#index argument is the name of the controller and the name of the action.

It generates Minitest/RSpec files according to test setting in .lotusrc. It generates an empty template with the template engine extension (template) setting in .lotusrc.

It generates the following files:

apps/web/controllers/dashboard/index.rb
spec/web/controllers/dashboard/index_spec.rb
apps/web/views/dashboard/index.rb
spec/web/views/dashboard/index_spec.rb
apps/web/templates/dashboard/index.html.erb (empty file)
Amend apps/web/config/routes.rb with a new route

Console

It starts a REPL, by using the engine defined in your Gemfile. It defaults to IRB. Run it from the root of the application.

% bundle exec lotus console

Database console

It starts a database REPL, by looking at your database configuration under `lib/. Run it from the root of the application.

% bundle exec lotus db console

It supports code reloading via the reload! command.

Routes

It prints the routes defined by the Lotus application(s).

% bundle exec lotus routes

Version

It prints the current Lotus version.

% bundle exec lotus version

Contributing

Fork it ( https://github.com/lotus/lotus/fork )
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create a new Pull Request

Versioning

Lotus uses Semantic Versioning 2.0.0