...

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

@@ -432,14 +432,14 @@ class Metadata(object):
         if key in self.user_metadata_keys():
             res = self.get(key, None)
             cmeta = self.get_user_metadata(key, make_copy=False)
+            name = unicode(cmeta['name'])
             if cmeta['datatype'] != 'composite' and (res is None or res == ''):
-                return (None, None, None, None)
+                return (name, res, None, None)
             orig_res = res
             cmeta = self.get_user_metadata(key, make_copy=False)
             if res is None or res == '':
-                return (None, None, None, None)
+                return (name, res, None, None)
             orig_res = res
-            name = unicode(cmeta['name'])
             datatype = cmeta['datatype']
             if datatype == 'text' and cmeta['is_multiple']:
                 res = u', '.join(res)
@@ -454,11 +454,12 @@ class Metadata(object):
 
         if key in field_metadata and field_metadata[key]['kind'] == 'field':
             res = self.get(key, None)
-            if res is None or res == '':
-                return (None, None, None, None)
-            orig_res = res
             fmeta = field_metadata[key]
             name = unicode(fmeta['name'])
+            if res is None or res == '':
+                return (name, res, None, None)
+            orig_res = res
+            name = unicode(fmeta['name'])
             datatype = fmeta['datatype']
             if key == 'authors':
                 res = authors_to_string(res)
@@ -508,9 +509,8 @@ class Metadata(object):
             fmt('Rights', unicode(self.rights))
         for key in self.user_metadata_keys():
             val = self.get(key, None)
-            if val is not None:
-                (name, val) = self.format_field(key)
-                fmt(name, unicode(val))
+            (name, val) = self.format_field(key)
+            fmt(name, unicode(val))
         return u'\n'.join(ans)
 
     def to_html(self):

src/calibre/gui2/library/models.py

@@ -327,7 +327,7 @@ class BooksModel(QAbstractTableModel): # {{{
         mi = self.db.get_metadata(idx)
         for key in mi.user_metadata_keys():
             name, val = mi.format_field(key)
-            if val is not None:
+            if val:
                 data[name] = val
         return data
 

src/calibre/library/server/mobile.py

@@ -125,7 +125,6 @@ def build_index(books, num, search, sort, order, start, total, url_base, CKEYS):
         series = u'[%s - %s]'%(book['series'], book['series_index']) \
                 if book['series'] else ''
         tags = u'Tags=[%s]'%book['tags'] if book['tags'] else ''
-        print tags
 
         ctext = ''
         for key in CKEYS:
@@ -231,7 +230,7 @@ class MobileServer(object):
                     return '%s:#:%s'%(name, unicode(val))
                 mi = self.db.get_metadata(record[CFM['id']['rec_index']], index_is_id=True)
                 name, val = mi.format_field(key)
-                if val is None:
+                if not val:
                     continue
                 datatype = CFM[key]['datatype']
                 if datatype in ['comments']:

src/calibre/library/server/opds.py

@@ -160,7 +160,7 @@ def ACQUISITION_ENTRY(item, version, db, updated, CFM, CKEYS):
     for key in CKEYS:
         mi = db.get_metadata(item[CFM['id']['rec_index']], index_is_id=True)
         name, val = mi.format_field(key)
-        if val is not None:
+        if val:
             datatype = CFM[key]['datatype']
             if datatype == 'text' and CFM[key]['is_multiple']:
                 extra.append('%s: %s<br />'%(name, format_tag_string(val, ',',