Allow MarcRecords to be looked up via ISBN

app/controllers/lookup_controller.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+##
+# Controller to lookup MARC records based on standard numbers (e.g. ISBN)
+class LookupController < ApplicationController
+  skip_authorization_check
+
+  def index
+    return {} if index_params[:isbn].blank?
+
+    @response = grouped_marc_records
+  end
+
+  def index_params
+    params.permit(:isbn)
+  end
+  helper_method :index_params
+
+  private
+
+  def grouped_marc_records
+    MarcRecord.includes(:organization).where(isbn: index_params[:isbn]).group_by(&:organization).select do |org, _|
+      can? :read, org
+    end
+  end
+end

app/models/upload.rb

@@ -69,12 +69,19 @@ def extract_marc_record_metadata(file, service)
         marc001: record['001']&.value,
         file_id: file.id,
         upload_id: id,
-        marc: record
+        marc: record,
+        isbn: record_isbn(record)
       )
 
       out.checksum ||= Digest::MD5.hexdigest(record.to_xml.to_s)
 
       yield out
     end
   end
+
+  def record_isbn(record)
+    marc020 = record['020'] || {}
+
+    (marc020['a'] || marc020['z'])&.[](/^x?\d+/)
+  end
 end

app/views/lookup/index.html.erb

@@ -0,0 +1,31 @@
+<div class="container">
+  <div class="d-flex justify-content-between">
+    <h1>Marc Records</h1>
+  </div>
+  <%= link_to "view as JSON", url_for(index_params.merge(format: :json)) %>
+
+  <table class="table table-striped organizations">
+    <thead>
+      <tr>
+        <th>marc001</th>
+        <th>Stream</th>
+        <th>Download</th>
+      </tr>
+    </thead>
+    <tbody>
+      <% @response.each do |organization, marc_records| %>
+        <tr>
+          <td colspan="3" class="bg-info font-weight-bold text-white"><%= organization.name %></td>
+        </tr>
+
+        <% marc_records.each do |marc_record| %>
+          <tr>
+            <td><%= marc_record.marc001 %></td>
+            <td><%= link_to(marc_record.stream.display_name, organization_stream_path(organization, marc_record.stream)) %></td>
+            <td><%= link_to('marc21', marc21_organization_marc_record_url(organization, marc_record)) %>, <%= link_to('marcxml', marcxml_organization_marc_record_url(organization, marc_record)) %></td>
+          </tr>
+        <% end %>
+      <% end %>
+    </tbody>
+  </table>
+</div>

app/views/lookup/index.json.jbuilder

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+json.total @response&.values&.sum(&:count) || 0
+json.isbn index_params[:isbn]
+json.organizations @response do |organization, records|
+  json.extract! organization, :id, :name, :slug
+  json.records records do |record|
+    json.extract! record, :id, :marc001, :bytecount, :length, :checksum
+    json.url organization_marc_record_url(record.organization, record)
+  end
+end

config/routes.rb

@@ -6,6 +6,7 @@
   get '/documentation/:id', to: 'pages#show', as: :pages
   get '/api', to: 'pages#api'
 
+  resources :lookup, only: :index
 
   get 'contact_emails/confirm/:token', to: 'contact_emails#confirm', as: :contact_email_confirmation
 

db/migrate/20201120180608_add_isbn_to_marc_record.rb

@@ -0,0 +1,6 @@
+class AddIsbnToMarcRecord < ActiveRecord::Migration[6.0]
+  def change
+    add_column :marc_records, :isbn, :string
+    add_index :marc_records, :isbn
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_11_20_154520) do
+ActiveRecord::Schema.define(version: 2020_11_20_180608) do
 
   create_table "active_storage_attachments", force: :cascade do |t|
     t.string "name", null: false
@@ -150,8 +150,10 @@
     t.bigint "length"
     t.bigint "index"
     t.string "checksum"
+    t.string "isbn"
     t.index ["file_id", "marc001"], name: "index_marc_records_on_file_id_and_marc001"
     t.index ["file_id"], name: "index_marc_records_on_file_id"
+    t.index ["isbn"], name: "index_marc_records_on_isbn"
     t.index ["upload_id", "marc001"], name: "index_marc_records_on_upload_id_and_marc001"
     t.index ["upload_id"], name: "index_marc_records_on_upload_id"
   end