Selection list management and form and view helpers.

##Key Features

• Manages one table to hold all selections items/dropdown lists or Radio Buttons ( tree )
• Dynamic lookup to find parent or children ( eg. Selection.priorities )
• Form helper to display lists

• f.selections :priorities # dropdowns
• f.radios :priorities # radio buttons
• f.check_boxes :priorities # check boxes

• Model helpers for joining tables ( eg. belongs_to_selection :priority )
• Matchers eg. @ticket.priority_high?
• Handling of archived items ( displaying if selected only )
• Ordering of lists based on alpha or numbered
• Default item handling

Add this line to your application's Gemfile:

gem 'selections'

And then execute:

$ bundle

Or install it yourself as:

$ gem install selections

Add this line to config/boot.rb under require 'bundler/setup' ... if using Rspec in your project

ENV["FIXTURES_PATH"] ||= 'spec/fixtures'

Scaffold generates basic model, controller views that support the tree adding and editing of selections. Also generates a sample selections.yml file.

rails generate selections_scaffold

First, you need to configure your selection model. We typically use Selection for this (although you can change the name), and should be generated such as:

rails generate model Selection name parent_id:integer system_code position_value:integer is_default:boolean is_system:boolean archived_at:datetime


class Selection < ActiveRecord::Base
  selectable
end

Selections table can contain one or many lists, it uses the acts_as_tree so each root is a new list meta example: (see below for example YML file).

• priority

• high
• medium
• low

• user_role

• admin
• owner
• user

From the rails console it is be possible to access these items directly using dynamic lookups:

Selection.priority => returns the parent row
Selection.user_role

Dynamic lookups support pluralization and will then return the children:

Selection.priorities  -> [high,med,low] records

If we had a controller for Ticket model with fields of:

• name
• priority_id

within the _form.html.erb just use the selections helper method:

<%= form_for(@ticket) do |f| %>

  <div>
    <%= f.label :name %><br />
    <%= f.text_field :name %>
  </div>

  <div>
    <%= f.label :priority %><br />
    <%= f.selections :priority %>
  </div>

  <div>
    <%= f.submit %>
  </div>
<% end %>

  f.selections :fieldname, options = {}, html_options = {}

The selections method excepts all the standard Ruby on Rails form helper options and html formatting - http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html#method-i-select

If you have a selection named differently to the foreign key eg. the foreign key is variety_id, you can use a system_code option.

<%= f.selections :variety, system_code: :category %>

If you want your input to be something other than a select tag then you can use the as tag to change it to a radio or check_boxes list. The as option will default to select.

  f.selections :ticket, options = { as: :radio }

  f.selections :ticket, options = { as: :check_boxes }

If you have naming conflicts/duplicates system_codes (parent codes) eg. category_id field for user and ticket models

Selections Data example

• user_category

• civilian
• programmer

• ticket_category

• high
• low

The fieldname within the user and ticket form can both be :category as the form helper will search for either 'category' or 'user_category' in the selections model.

users/_form.html.erb

  <%= f.selections :category %>

This will automatically look up the 'user_category' selections if 'category' does not exist

Next, you need to tell models that have a selectable association. These are belongs_to associations which pull their values from the selections model. Assuming you have a Ticket model with a foreign key of priority_id, you can set this up like so:

class Ticket < ActiveRecord::Base

  belongs_to_selection :priority

end

If you want a model to have a has_many relationship to a selections list you can create an array field and use the has_many_selections method like so:

class Ticket < ActiveRecord::Base

  has_many_selections :priorities # DB attribute is priorities_ids

end

From an instance of a ticket within a view the belongs_to selection will return string (to_s). eg: show.html.erb

<p>
  <b>Priority:</b>
  <%= @ticket.priority %>  # Instead of this @ticket.priority.try(:name)
</p>

Selections supports predicate methods if you add the predicates: true option to the belongs_to_selection model helper, as an example:

instead of needing to do

  if @ticket.priority == Selection.ticket_priority_high

you can check directly on the instance:

  if @ticket.priority_high?

Selections supports scope methods if you add the scopes: true option to the belongs_to_selection model helper, as an example:

instead of create a scope for

  scope :ticket_priority_high, -> { where(priority_id: Selection.ticket_priority_high.id) }

this scope is provided for you:

  @ticket.ticket_priority_high

By default the belongs_to_selection model helper provides an instance method for displaying the name or names of the saved selection value as an example:

Instead of

  @ticket.priority.name

You can now just do

  @ticket.priority_name

In a new form the selections list will have blank top row unless a default item is set in the selections eg. Medium Priority, then there will be no blank row and the default item will be selected.

When editing a form, by default the blank row will not be displayed. Use the options include_blank: true option to override.

On a new form items that are archived in Selections will not appear in the selection list. When editing an existing record the list will only contain un-archived items, unless the item selected is archived it will then appear.

eg. A ticket has a priority set to high, later the high selection list item was archived, when we edit the ticket record again the item will show in the list even though it is archived.

The list will by default display in alphanumeric order, unless you add position values and then it will display in the values.

On creation of a new item in Selections the system_code field will be automatically generated based on parent and item name if left blank.

If you use a class name other than Selection as your selection model, you must tell selections so by adding the following to a new file, config/initializers/selections.rb:

Selections.model { YourSelectionModel }

When using fixtures with the label same as the system_code, use this method to return the ID of the of the fixture and use this in Factories instead of using a lookup as it does not need a DB search.

Fixture File

priority_high:
   name: Priorities
   system_code: priority_high
   parent: priority

Don't do this as it will need a DB lookup

  priority: { Selection.priority_high }

Do this as it will be much quicker

 priority_id: { Selection.label_to_id(:priority_high) }

• Suggestions please

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

priority:
  name: Priorities
  parent:
  position_value:
  system_code: priority
  is_system: false
priority_high:
  name: High
  parent: priority
  position_value: 30
  system_code: $LABEL
  is_system:
priority_medium:
  name: Medium
  parent: priority
  position_value: 20
  system_code: $LABEL
  is_system:
priority_low:
  name: Low
  parent: priority
  position_value: 10
  system_code: $LABEL
  is_system:
  is_default: true


contact_category:
  name: Contact Categories
  parent:
  position_value:
  system_code: contact_category
  is_system: false
contact_category_junior:
  name: Junior Tech
  parent: contact_category
  position_value:
  system_code: $LABEL
  is_system:
contact_category_senior:
  name: Senior Tech
  parent: contact_category
  position_value:
  system_code: $LABEL
  is_system:
contact_category_manager:
  name: Manager
  parent: contact_category
  position_value:
  system_code: $LABEL
  is_system:
  archived_at: <%= Time.now %>
contact_category_ceo:
  name: CEO
  parent: contact_category
  position_value:
  system_code: $LABEL
  is_system: