EPUB: Ensure that the calibre book uuid is present in the opf of EPUB files converted/exported from the GUI

src/calibre/ebooks/metadata/epub.py

@@ -291,6 +291,8 @@ def set_metadata(stream, mi, apply_null=False, update_timestamp=False):
 
 
     reader.opf.smart_update(mi)
+    if getattr(mi, 'uuid', None):
+        reader.opf.application_id = mi.uuid
     if apply_null:
         if not getattr(mi, 'series', None):
             reader.opf.series = None

src/calibre/ebooks/metadata/opf2.py

@@ -941,12 +941,11 @@ class OPF(object): # {{{
                 return self.get_text(match) or None
 
         def fset(self, val):
-            matches = self.application_id_path(self.metadata)
-            if not matches:
-                attrib = {'{%s}scheme'%self.NAMESPACES['opf']: 'calibre'}
-                matches = [self.create_metadata_element('identifier',
-                                                        attrib=attrib)]
-            self.set_text(matches[0], unicode(val))
+            for x in tuple(self.application_id_path(self.metadata)):
+                x.getparent().remove(x)
+            attrib = {'{%s}scheme'%self.NAMESPACES['opf']: 'calibre'}
+            self.set_text(self.create_metadata_element(
+                'identifier', attrib=attrib), unicode(val))
 
         return property(fget=fget, fset=fset)
 

src/calibre/ebooks/oeb/transforms/metadata.py

@@ -115,8 +115,11 @@ class MergeMetadata(object):
         if mi.uuid is not None:
             m.filter('identifier', lambda x:x.id=='uuid_id')
             self.oeb.metadata.add('identifier', mi.uuid, id='uuid_id',
-                                    scheme='uuid')
+                                  scheme='uuid')
             self.oeb.uid = self.oeb.metadata.identifier[-1]
+        if mi.application_id is not None:
+            m.filter('identifier', lambda x:x.scheme=='calibre')
+            self.oeb.metadata.add('identifier', mi.application_id, scheme='calibre')
 
     def set_cover(self, mi, prefer_metadata_cover):
         cdata, ext = '', 'jpg'

src/calibre/gui2/convert/metadata.py

@@ -26,6 +26,7 @@ def create_opf_file(db, book_id):
     mi.application_id = uuid.uuid4()
     old_cover = mi.cover
     mi.cover = None
+    mi.application_id = mi.uuid
     raw = metadata_to_opf(mi)
     mi.cover = old_cover
     opf_file = PersistentTemporaryFile('.opf')