Add Metadata to Views, Presenter, and Solr - RepoCamp/ohsu2018 GitHub Wiki

Goals:

• Add the field to the show view
  • Add a show feature
  • Add the new metadata field to your show feature
  • Make a custom presenter for our Work class
• Add a field to views and solr
  • Add your field to the solr index
  • Add a field to solr document
  • Add a field to the view partial
• Pair exercise

Setup

(OPTIONAL) Save your current changes

If you have changes in your current branch -- you can check on this via git status -- you'll want to save those before starting this lesson (which uses a separate branch):

• git checkout -b wip_lesson_6_start
• git add .
• git commit -m 'checkpoint before beginning second metadata lesson'

Check out working branch

git checkout lesson_6_start

NOTE: If you make experimental changes and want to get back to the minimal code state necessary to run this lesson, you can check the starting code out again using:
git checkout lesson_6_start

Add the field to the show view

In part one of this tutorial, we added functionality for new fields when creating a new Work. For part two, we're going focus on displaying a Work.

Add a Show feature test

1. Create a new file at spec/features/show_work_spec.rb.

require 'rails_helper'

RSpec.feature 'Display an Work' do
  let(:title)      { ['Journey to Skull Island'] }
  let(:creator)    { ['Quest, Jane'] }
  let(:keyword)    { ['Pirates', 'Adventure'] }
  let(:visibility) { Hydra::AccessControls::AccessRight::VISIBILITY_TEXT_VALUE_PUBLIC }
  let(:user)       { '[email protected]' } 

  let :work do
    Work.create(title:      title,
                creator:    creator,
                keyword:    keyword,
                visibility: visibility,
                depositor:  user)
  end

  scenario "Show a public Work" do
    visit("/concern/works/#{work.id}")

    expect(page).to have_content work.title.first
    expect(page).to have_content work.creator.first
    expect(page).to have_content work.keyword.first
    expect(page).to have_content work.keyword.last
  end
end

2. Run your test suite (rails ci or rspec spec). Everything should pass.

Add the new metadata field to your show feature

1. Add your new metadata field to the show spec you just created. You'll need to add it in three places:
   1. As a let statement, where you define the value: let(:year) { ['2010'] }
   2. In the Work.new block: year: year
   3. In the expectations: expect(page).to have_content work.year.first
2. Run your test suite again (rspec spec). It should fail with the message Failure/Error: expect(page).to have_content work.year.first.

This tells us that our test setup ran successfully (a Work was created with a year field) but the show page doesn't display that field yet.

Modify the presenter for our Work class

Recall that Rails uses an "MVC" or "model-view-controller" pattern. In addition to models, views, and controllers, we also have presenters, sometimes also referred to as a "Decorator" or "View-Model." The presenter is responsible for translating values from the model to a presentable form.

Example:

class BookPresenter
  def initialize(book)
    @book = book
  end

  delegate :title, :creator, to: :@book

  def glitter_title
    '★' + @book.title + '☆'
  end
end

Customize our work-specific presenter

As always, we want to write our test first.

1. Hyrax generated app/presenters/hyrax/work_presenter.rb and spec/presenters/hyrax/work_presenter_spec.rb for you when you created your Work work type. Open these files and take a look.
2. Edit spec/presenters/hyrax/work_presenter_spec.rb. It is only a stubbed spec right now.

require 'rails_helper'

RSpec.describe Hyrax::WorkPresenter do
  subject(:presenter) { described_class.new(SolrDocument.new(work.to_solr), nil) }

  let(:title)      { ['Journey to Skull Island'] }
  let(:creator)    { ['Quest, Jane'] }
  let(:keyword)    { ['Pirates', 'Adventure'] }
  let(:visibility) { Hydra::AccessControls::AccessRight::VISIBILITY_TEXT_VALUE_PUBLIC }
  let(:user)       { '[email protected]' } 

  let :work do
    Work.new(title:      title,
             creator:    creator,
             keyword:    keyword,
             visibility: visibility,
             depositor:  user)
  end

  it { is_expected.to have_attributes(title: title, year: year) }
end

3. Run your test suite (rails ci). It will fail with the message Failure/Error: it { is_expected.to delegate_method(:year).to(:solr_document) }
4. Add this line to your work_presenter.rb file:

  delegate :year, to: :solr_document

Use our custom presenter

In order to use our custom presenter, our Work class has to know about it. Normally, you would have to manually add the custom presenter to the relevant controller, in this case app/controllers/hyrax/works_controller.rb. However, Hyrax did this for you when you ran the work type generator. Open the app/controllers/hyrax/works_controller.rb file and note that it is configured to use Hyrax::WorkPresenter.

  self.show_presenter = Hyrax::WorkPresenter

OH NO! Run your test suite again,

     Failure/Error: delegate :year, to: :solr_document
     
     NoMethodError:
       undefined method `year' for #<SolrDocument:0x000000000c855028>

Discussion

• Where does the presenter get its data?
• What does it mean that we "delegate" to solr_document?
• What advantages are there to our "presenter" pattern vs. using Work throughout?

---

Check out working branch

git checkout lesson_6_mid

NOTE: If you make experimental changes and want to get back to the minimal code state necessary to run this lesson, you can check the starting code out again using:
git checkout lesson_6_mid

Add a field to view partial and solr

Add your field to the solr index

1. Edit app/models/work.rb and add instructions for how the year field should be indexed:

  property :year, predicate: "http://www.europeana.eu/schemas/edm/year" do |index|
    index.as :stored_searchable
  end

Add the field to solr_document

1. Edit app/models/solr_document.rb and add this method:

  def year
    self[Solrizer.solr_name('year')]
  end

Add the field to the view partial

1. Copy Hyrax's app/views/hyrax/base/_attribute_rows.html.erb to the same directory structure in your app
2. Edit your newly created local copy of _attribute_rows.html.erb to include your metadata field:

  <%= presenter.attribute_to_html(:year) %>

3. Run your test suite again (rails ci) and your feature test should now pass

Note: You can see all the changes made during this exercise on the github repo.

Pair exercise

We added one metadata field here: year. Choose either extent or references and add a second metadata field. Or, define your own metadata field, as long as you pick something that can be a simple string.