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https://github.com/floere/representer

DEPRECATED: PLEASE SEE THE view_models LINK BELOW.
https://github.com/floere/representer

Last synced: 2 months ago
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DEPRECATED: PLEASE SEE THE view_models LINK BELOW.

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README 

        
# Representers for Rails

# A possible representer solution, i.e. no view logic in model code.

# Ask/Write [email protected] if you have questions/feedback, thanks! :)

# Fork if you have improvements. Tell me where to merge them from, thanks!

#

# Problem: Display Methods are not well placed either in

# * models: Violation of the MVC principle.

# * helpers: No Polymorphism.

# Solution:

# A thin proxy layer over a model, with access to the controller, used by the view or controller.

# 

# IMPORTANT NOTE:

# As of yet it is needed to copy the representer/views/representers/collection

# directory to the corresponding location in app/views/representers/collection.

# This is only needed if you wish to use the collection rpresenter.

# Note: Rewrite the collection templates as needed, they are rather basic.

#

# * Getting a representer in a view or a controller.

#

# Call representer_for:

# Note: By convention, uses Representers::Model::Class::Name, thus prefixing Representers:: to

#       the model class name.

presenter_instance = representer_for model_instance



# * Getting a collection representer in a view.

#

# The collection representer renders each of the given items with its representer.

#

# Call collection_presenter_for:

collection_presenter_instance = collection_presenter_for enumerable_containing_model_instances

# Rendering a list.

collection_presenter_instance.list

# Rendering a collection.

collection_presenter_instance.collection

# Rendering a table.

collection_presenter_instance.table

# Rendering a pagination.

# Note: Only works if the passed parameter for collection_presenter_for is a PaginationEnumeration.

collection_presenter_instance.pagination



# * Writing filtered delegate methods on the representer.

#

# Will create two delegate methods first_name and last_name that delegate to the model.

model_reader :first_name, :last_name

# Will create a description delegate method that filters the model value through h.

model_reader :description, :filter_through => :h

# Will create a description delegate method that filters the model value through first textilize, then h.

model_reader :description, :filter_through => [:textilize, :h]

# Will create both a first_name and last_name delegate method

# that filters the model value through first textilize, then h.

model_reader :first_name, :last_name, :filter_through => [:textilize, :h]

# Note: Filter methods can be any method on the representer with arity 1.



# * Rendering representer templates

#

# Use render_as(template_name, format = nil).

#

# Gets a Representers::Model::Class instance

presenter = representer_for Model::Class.new

# Gets a Representers:: instance

presenter = representer_for model_instance

# Renders the 'example' partial in representers/model/class.

# Note: Renders a format depending on the request. ../index.text will render example.text.erb.

presenter.render_as :example

# Renders the 'example.text.erb' partial in representers/model/class.

presenter.render_as :example, :text



# * Rails Helpers in Representers

#

# Use helper as in the controller.

helper ActionView::Helpers::UrlHelper

helper ApplicationHelper

# Note: It is helpful to create a superclass to all representers in the project

#       with generally used helpers.

# We use Representers::Project a lot, for example. See example below.



# * Controller Delegate Methods

#

# Use controller_method(*args).

#

# Delegates current_user and logger on the representer to the controller.

controller_method :current_user, :logger



# * Big Example

#

# The following classes all have specs of course ;) But are not shown since they don't help the example.



# Representers superclass for this project.

#

# We include all of Rails' helpers for the representers in this project.

# Also, we include the ApplicationHelper.

#

# We delegate logger and current_user calls in the representers to

# the active controller.

#

class Representers::Project < Representers::Base

  

  # All of Rails' standard helpers.

  helper ActionView::Helpers::ActiveRecordHelper

  helper ActionView::Helpers::TagHelper

  helper ActionView::Helpers::FormTagHelper

  helper ActionView::Helpers::FormOptionsHelper

  helper ActionView::Helpers::FormHelper

  helper ActionView::Helpers::UrlHelper

  helper ActionView::Helpers::AssetTagHelper

  helper ActionView::Helpers::PrototypeHelper

  helper ActionView::Helpers::TextHelper

  

  helper ApplicationHelper

  

  controller_method :logger, :current_user

  

end



# All items have a description that needs to be filtered by textilize.

#

class Representers::Item < Representers::Project

  model_reader :description, :filter_through => :textilize

  # Use price in the view as follows:

  # = representer.price - will display e.g. 16.57 CHF, since it is filtered first through localize_currency

  model_reader :price, :filter_through => :localize_currency

  

  # Converts a database price tag to the users chosen value, with the users preferred currency appended.

  # If the user is Swiss, localize_currency will convert 10 Euros to "16.57 CHF" 

  #

  def localize_currency(price_in_euros)

    converted_price = current_user.convert_price(price_in_euros)

    "#{converted_price} #{current_user.currency.to_s}"

  end

end



# This class also has partial templates in the directory

#   app/views/representers/book

# that are called

#   _cart_item.html.haml

#   _cart_item.text.erb

#

# Call representer_for on a book in the view or controller to get this representer.

#

class Representers::Book < Representers::Item

  model_reader :author, :title, :pages

  model_reader :excerpt, :filter_through => :textilize

  

  def header

    content_tag(:h1, "#{author} – #{title}")

  end

  

  def full_description

    content_tag(:p, "#{excerpt} #{description}", :class => 'description full')

  end

end



# This class also has partial templates in the directory

#   app/views/representers/toy

# that are called

#   _cart_item.html.haml

#   _cart_item.text.erb

#

# Call representer_for on a toy in the view or controller to get this representer.

#

class Representers::Toy < Representers::Item

  model_reader :starting_age, :small_dangerous_parts

  

  def obligatory_parental_warning

    "Warning, this toy can only be used by kids ages #{starting_age} and up. Your department of health. Thank you."

  end

  

end