...

src/calibre/library/field_metadata.py

@@ -497,6 +497,13 @@ class FieldMetadata(dict):
     def is_custom_field(self, key):
         return key.startswith(self.custom_field_prefix)
 
+    def is_ignorable_field(self, key):
+        'Custom fields and user categories are ignorable'
+        return self.is_custom_field(key) or key.startswith('@')
+
+    def ignorable_field_keys(self):
+        return [k for k in self._tb_cats.iterkeys() if self.is_ignorable_field(k)]
+
     def is_series_index(self, key):
         m = self[key]
         return (m['datatype'] == 'float' and key.endswith('_index') and

src/calibre/library/server/__init__.py

@@ -51,7 +51,7 @@ def server_config(defaults=None):
     return c
 
 def custom_fields_to_display(db):
-    ckeys = db.custom_field_keys()
+    ckeys = db.field_metadata.ignorable_field_keys()
     yes_fields = set(tweaks['content_server_will_display'])
     no_fields = set(tweaks['content_server_wont_display'])
     if '*' in yes_fields:

src/calibre/library/server/ajax.py

@@ -300,7 +300,8 @@ class AjaxServer(object):
             meta = category_meta.get(category, None)
             if meta is None:
                 continue
-            if meta['is_custom'] and category not in displayed_custom_fields:
+            if category_meta.is_ignorable_field(category) and \
+                        category not in displayed_custom_fields:
                 continue
             display_name = meta['name']
             if category.startswith('@'):

src/calibre/library/server/browse.py

@@ -269,7 +269,7 @@ class BrowseServer(object):
             for x in fm.sortable_field_keys():
                 if x in ('ondevice', 'formats', 'sort'):
                     continue
-                if fm[x]['is_custom'] and x not in displayed_custom_fields:
+                if fm.is_ignorable_field(x) and x not in displayed_custom_fields:
                     continue
                 if x == 'comments' or fm[x]['datatype'] == 'comments':
                     continue
@@ -369,7 +369,8 @@ class BrowseServer(object):
             meta = category_meta.get(category, None)
             if meta is None:
                 continue
-            if meta['is_custom'] and category not in displayed_custom_fields:
+            if self.db.field_metadata.is_ignorable_field(category) and \
+                        category not in displayed_custom_fields:
                 continue
             # get the icon files
             main_cat = (category.partition('.')[0]) if hasattr(category,
@@ -836,7 +837,8 @@ class BrowseServer(object):
             displayed_custom_fields = custom_fields_to_display(self.db)
             for field, m in list(mi.get_all_standard_metadata(False).items()) + \
                     list(mi.get_all_user_metadata(False).items()):
-                if m['is_custom'] and field not in displayed_custom_fields:
+                if self.db.field_metadata.is_ignorable_field(field) and \
+                                field not in displayed_custom_fields:
                     continue
                 if m['datatype'] == 'comments' or field == 'comments' or (
                         m['datatype'] == 'composite' and \

src/calibre/library/server/opds.py

@@ -594,7 +594,7 @@ class OPDSServer(object):
             meta = category_meta.get(category, None)
             if meta is None:
                 continue
-            if category_meta.is_custom_field(category) and \
+            if category_meta.is_ignorable_field(category) and \
                                 category not in custom_fields_to_display(self.db):
                 continue
             cats.append((meta['name'], meta['name'], 'N'+category))