embed search query into pdf viewer

app/helpers/pdf_viewer_helper.rb

@@ -0,0 +1,20 @@
+module PdfViewerHelper
+  def viewer_url(path)
+    "/web/viewer.html?file=#{path}##{query_param}"
+  end
+
+  def query_param
+    return unless search_query
+    "search=#{search_query}&phrase=true"
+  end
+
+  private
+
+  def search_query
+    search && search.respond_to?(:query_params) && search.query_params[:q]
+  end
+
+  def search
+    current_search_session
+  end
+end

app/views/hyrax/file_sets/media_display/_pdf.html.erb

@@ -5,7 +5,7 @@
 
     <iframe id="pdf-viewer" width="100%" height="600px" frameborder="0"
             scrolling="no" marginheight="0" marginwidth="0"
-            title="PDF Document" src="/web/viewer.html?file=<%= hyrax.download_path(file_set) %>"></iframe>
+            title="PDF Document" src="<%= viewer_url(download_path(file_set)) %>"></iframe>
 <% else %>
     <div>
       <%= image_tag thumbnail_url(file_set),

public/web/viewer-find-custom.js

@@ -0,0 +1,18 @@
+// fills in the findInput search box with the
+// provided query term (when present), only on load
+document.addEventListener('pagerendered', function (ev) {
+  var findInput = document.getElementById('findInput')
+  var app = PDFViewerApplication
+
+  app.eventBus.on('pagesloaded', function () {
+    var findController = app.findController || {}
+    var state = findController.state || {}
+    var query = state.query || null
+
+    if (!query) {
+      return
+    }
+
+    findInput.value = query
+  })
+})

public/web/viewer.html

@@ -354,5 +354,8 @@
 
     </div> <!-- outerContainer -->
     <div id="printContainer"></div>
+
+    <!-- fill in the search bar if a query exists + the bar isn't filled already -->
+    <script src="viewer-find-custom.js"></script>
   </body>
 </html>