Permit configurable replacement of search tracking with client session storage

app/components/blacklight/search_context/client_applied_params_component.html.erb

@@ -0,0 +1,4 @@
+<div id="appliedParams" class="clearfix constraints-container">
+  <%= render 'start_over' %>
+  <%= link_to t('blacklight.back_to_search'), search_action_path(only_path: true), class: 'btn btn-outline-secondary back-to-catalog', aria: { live: "off", disabled: true }, hidden: true %>
+</div>

app/components/blacklight/search_context/client_applied_params_component.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module Blacklight
+  module SearchContext
+    class ClientAppliedParamsComponent < Blacklight::Component
+      delegate :search_action_path, to: :helpers
+      def render?
+        controller.params[:counter]
+      end
+    end
+  end
+end

app/components/blacklight/search_context/client_item_pagination_component.html.erb

@@ -0,0 +1,10 @@
+<div class='pagination-search-widgets'>
+
+  <div class="page-links" data-page-links-url="<%= page_links_url %>" aria-live="polite">
+    <%= link_to_previous_document %> |
+
+    <%= item_page_entry_info %> |
+
+    <%= link_to_next_document %>
+  </div>
+</div>

app/components/blacklight/search_context/client_item_pagination_component.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+module Blacklight
+  module SearchContext
+    class ClientItemPaginationComponent < Blacklight::Component
+      delegate :search_action_path, to: :helpers
+
+      def initialize(search_context:, **_args)
+        @counter = search_context&.fetch(:counter, nil)
+      end
+
+      def render?
+        @counter.present?
+      end
+
+      def page_links_url
+        search_action_path action: 'page_links', counter: @counter
+      end
+
+      ##
+      # Displays "showing X of Y items" message.
+      #
+      # @return [String]
+      def item_page_entry_info
+        # rubocop:disable Rails/OutputSafety
+        t('blacklight.search.entry_pagination_info.other', current: "<span class=\"pagination-counter-delimited\"></span>",
+                                                           total: "<span class=\"pagination-total-delimited\"></span>",
+                                                           count: "<span class=\"pagination-total-raw\"></span>").html_safe
+        # rubocop:enable Rails/OutputSafety
+      end
+
+      # Displays a stub link for previous document to be activated by client script
+      # @return [String]
+      def link_to_previous_document
+        # rubocop:disable Rails/OutputSafety
+        link_opts = { class: ['previous'], rel: 'prev', aria: { disabled: true } }
+        content_tag :a, link_opts do
+          tag.span raw(t('views.pagination.previous')), class: 'previous'
+        end
+        # rubocop:enable Rails/OutputSafety
+      end
+
+      # Displays a stub link for next document to be activated by client script
+      # @return [String]
+      def link_to_next_document
+        # rubocop:disable Rails/OutputSafety
+        link_opts = { class: ['next'], rel: 'next', aria: { disabled: true } }
+        content_tag :a, link_opts do
+          tag.span raw(t('views.pagination.next')), class: 'next'
+        end
+        # rubocop:enable Rails/OutputSafety
+      end
+    end
+  end
+end

app/components/blacklight/search_context/server_applied_params_component.html.erb

@@ -0,0 +1,4 @@
+<div id="appliedParams" class="clearfix constraints-container">
+  <%= render 'start_over' %>
+  <%= link_back_to_catalog class: 'btn btn-outline-secondary' %>
+</div>

app/components/blacklight/search_context/server_applied_params_component.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module Blacklight
+  module SearchContext
+    class ServerAppliedParamsComponent < Blacklight::Component
+      delegate :current_search_session, :link_back_to_catalog, to: :helpers
+
+      def render?
+        current_search_session
+      end
+    end
+  end
+end

app/components/blacklight/search_context_component.rb

@@ -4,13 +4,14 @@ module Blacklight
   class SearchContextComponent < Blacklight::Component
     with_collection_parameter :search_context
 
-    def initialize(search_context:, search_session:)
+    def initialize(search_context:, search_session:, current_document:)
       @search_context = search_context
       @search_session = search_session
+      @current_document_id = current_document.id
     end
 
     def render?
-      @search_context.present? && (@search_context[:prev] || @search_context[:next])
+      @search_context.present? && (@search_context[:prev] || @search_context[:next]) && (@search_session['document_id'] == @current_document_id)
     end
 
     ##

app/controllers/concerns/blacklight/bookmarks.rb

@@ -15,7 +15,7 @@ module Blacklight::Bookmarks
 
     before_action :verify_user
 
-    blacklight_config.track_search_session = false
+    blacklight_config.track_search_session.storage = false
     blacklight_config.http_method = Blacklight::Engine.config.blacklight.bookmarks_http_method
     blacklight_config.add_results_collection_tool(:clear_bookmarks_widget)
 

app/controllers/concerns/blacklight/search_context.rb

@@ -28,6 +28,28 @@ def searches_from_history
     session[:history].blank? ? ::Search.none : ::Search.where(id: session[:history]).order("updated_at desc")
   end
 
+  # GET previous and next document json for the document specified by
+  # the counter param in current search
+  def page_links
+    counter_param = params.delete(:counter)
+    @page_link_data = {}
+    if counter_param
+      index = counter_param.to_i - 1
+      response, documents = search_service.previous_and_next_documents_for_search index, search_state.reset_search
+      if documents.detect(&:present?)
+        @page_link_data[:prev] = page_links_document_path(documents.first, index)
+        @page_link_data[:next] = page_links_document_path(documents.last, index + 2)
+      end
+      if response&.total && response.total.positive?
+        @page_link_data[:counterRaw] = counter_param
+        @page_link_data[:counterDelimited] = helpers.number_with_delimiter(counter_param.to_i)
+        @page_link_data[:totalRaw] = response.total
+        @page_link_data[:totalDelimited] = helpers.number_with_delimiter(response.total)
+      end
+    end
+    render json: @page_link_data
+  end
+
   private
 
   # sets up the session[:search] hash if it doesn't already exist
@@ -85,6 +107,8 @@ def agent_is_crawler?
   end
 
   def find_or_initialize_search_session_from_params params
+    return unless blacklight_config.track_search_session.storage == 'server'
+
     params_copy = params.reject { |k, v| nonpersisted_search_session_params.include?(k.to_sym) || v.blank? }
 
     return if params_copy.reject { |k, _v| [:action, :controller].include? k.to_sym }.blank?
@@ -127,15 +151,31 @@ def blacklisted_search_session_params
   # calls setup_previous_document then setup_next_document.
   # used in the show action for single view pagination.
   def setup_next_and_previous_documents
-    if search_session['counter'] && current_search_session
-      index = search_session['counter'].to_i - 1
-      response, documents = search_service.previous_and_next_documents_for_search index, search_state.reset(current_search_session.query_params)
+    return { counter: params[:counter] } if setup_next_and_previous_on_client?
+    return nil unless setup_next_and_previous_on_server?
 
-      search_session['total'] = response.total
-      { prev: documents.first, next: documents.last }
-    end
+    index = search_session['counter'].to_i - 1
+    response, documents = search_service.previous_and_next_documents_for_search index, search_state.reset(current_search_session.query_params)
+
+    search_session['total'] = response.total
+    { prev: documents.first, next: documents.last }
   rescue Blacklight::Exceptions::InvalidRequest => e
     logger&.warn "Unable to setup next and previous documents: #{e}"
     nil
   end
+
+  def setup_next_and_previous_on_server?
+    search_session['counter'] && current_search_session && blacklight_config.track_search_session.storage == 'server'
+  end
+
+  def setup_next_and_previous_on_client?
+    params[:counter] && blacklight_config.track_search_session.storage == 'client'
+  end
+
+  def page_links_document_path(document, counter)
+    return nil unless document
+    return search_state.url_for_document(document, counter: counter) if blacklight_config.view_config(:show).route
+
+    solr_document_path(document, counter: counter)
+  end
 end