Prospecto

Simple rails presenter with an emphasis on just using ruby.

Add this line to your application's Gemfile:

gem 'prospecto'

And then execute:

$ bundle

Or install it yourself as:

$ gem install prospecto

There are a few problems that prospecto was created to solve.

1. Views are hard and ineffective to test.
2. Code is often common between the output formats.

We feel that (our interpretation of) the presenter pattern is the answer to these problems. To be clear, you do not need a library to implement the presenter pattern. The purpose of prospecto is to provide some syntactic sugar and structure.

To start it is recommended (but not required) that you generate an ApplicationPresenter. This will act as a base class for all other presenters much like an ApplicationController. Just use the built in generator:

$ rails generate prospecto:install

You are now ready to start creating presenters. In prospecto a presenter does not necessarily correlate with a model (though this often ends up as the case), instead a presenter represents a view or family of views depending on the situation. This is up to you to decide.

To create a simple presenter use the included generator:

$rails generate prospecto:presenter User

By default all presenters inherit from the Prospecto::PresenterView class. This class is optional and exists solely to provide some sugar for creating constructors for objects.

The accepts method is the most encouraged. It creates a private accessor for the provided value.

class UserPresenter < Prospecto::PresenterView
  accepts :user

  def name
    "#{user.first} #{user.last}"
  end
end

view = UserPresenter.new(user: @user)
puts user.name

The decorates method allows the provided value to be accessed directly on the presenter. This is simalar to how something like draper works.

class UserPresenter < Prospecto::PresenterView
  decorates :user
end

view = UserPresenter.new(user: @user)
puts "#{view.first} #{view.last}"

The proxies method creates named methods on the presenter for the provided value.

class UserPresenter < Prospecto::PresenterView
  proxies :user
end

view = UserPresenter.new(user: @user)
puts "#{view.user_first} #{view.user_last}"

The presents method is creates a public accessor for the provided value. Use of this is discouraged.

class UserPresenter < Prospecto::PresenterView
  presents :user_public
end

view = UserPresenter.new(user_public: @user)
puts "#{view.user_public.first} #{view.user_public.last}"

How you use the presenters is very loose. Since you are just dealing with pretty vanilla ruby objects you can instantiate where it makes the most sense for your project. Usually basic usage looks something like this.

class UserController < ApplicationController
  def index
    users = User.where(active: true)
    @view = UserPresenter.new(users: users)
  end
end

You then use the @view object like normal in the view.

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Added some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

Development for prospecto is sponsored mainly by my employer Voonami since we use it heavily in house.