Book details: Show a clickable link to open the data files folder when extra data files are present for the book

src/calibre/ebooks/metadata/book/render.py

@@ -6,6 +6,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os
 from functools import partial
+from contextlib import suppress
 
 from calibre import prepare_string_for_xml, force_unicode
 from calibre.ebooks.metadata import fmt_sidx, rating_to_stars
@@ -201,7 +202,6 @@ def mi_to_html(
                 path = force_unicode(mi.path, filesystem_encoding)
                 scheme = 'devpath' if isdevice else 'path'
                 loc = path if isdevice else book_id
-                pathstr = _('Click to open')
                 extra = ''
                 if isdevice:
                     durl = path
@@ -211,7 +211,15 @@ def mi_to_html(
                             prepare_string_for_xml(durl))
                 if show_links:
                     link = '<a href="{}" title="{}">{}</a>{}'.format(action(scheme, book_id=book_id, loc=loc),
-                        prepare_string_for_xml(path, True), pathstr, extra)
+                        prepare_string_for_xml(path, True), _('Click to open'), extra)
+                    if not isdevice:
+                        data_path = os.path.join(path, 'data')
+                        with suppress(OSError):
+                            if os.listdir(data_path):
+                                link += ' \xa0 <a href="{}" title="{}">{}</a>'.format(
+                                    action('data-path', book_id=book_id, loc=book_id),
+                                    prepare_string_for_xml(data_path, True), _('Data files'))
+
                 else:
                     link = prepare_string_for_xml(path, True)
                 ans.append((field, row % (name, link)))

src/calibre/gui2/actions/view.py

@@ -281,6 +281,10 @@ class ViewAction(InterfaceAction):
         path = self.gui.library_view.model().db.abspath(id_, index_is_id=True)
         open_local_file(path)
 
+    def view_data_folder_for_id(self, id_):
+        path = self.gui.library_view.model().db.abspath(id_, index_is_id=True)
+        open_local_file(os.path.join(path, 'data'))
+
     def view_book(self, triggered):
         rows = self.gui.current_view().selectionModel().selectedRows()
         self._view_books(rows)

src/calibre/gui2/book_details.py

@@ -1088,6 +1088,7 @@ class BookDetails(DetailsLayout):  # {{{
 
     show_book_info = pyqtSignal()
     open_containing_folder = pyqtSignal(int)
+    open_data_folder = pyqtSignal(int)
     view_specific_format = pyqtSignal(int, object)
     search_requested = pyqtSignal(object, object)
     remove_specific_format = pyqtSignal(int, object)
@@ -1237,6 +1238,8 @@ class BookDetails(DetailsLayout):  # {{{
                     browse(data['url'])
             elif dt == 'path':
                 self.open_containing_folder.emit(int(data['loc']))
+            elif dt == 'data-path':
+                self.open_data_folder.emit(int(data['loc']))
             elif dt == 'devpath':
                 self.view_device_book.emit(data['loc'])
         else:

src/calibre/gui2/init.py

@@ -669,6 +669,7 @@ class LayoutMixin:  # {{{
                 self.iactions['Add Books'].remote_file_dropped_on_book,
                 type=Qt.ConnectionType.QueuedConnection)
         self.book_details.open_containing_folder.connect(self.iactions['View'].view_folder_for_id)
+        self.book_details.open_data_folder.connect(self.iactions['View'].view_data_folder_for_id)
         self.book_details.view_specific_format.connect(self.iactions['View'].view_format_by_id)
         self.book_details.search_requested.connect(self.set_search_string_with_append)
         self.book_details.remove_specific_format.connect(