EPUB metadata: Add an option to disable adding of cover images to EPUB files that declare no cover image in their metadata (Preferences->Plugins->Customize the Set EPUB metadata plugin)

src/calibre/customize/builtins.py

@@ -432,7 +432,13 @@ class EPUBMetadataWriter(MetadataWriterPlugin):
 
     def set_metadata(self, stream, mi, type):
         from calibre.ebooks.metadata.epub import set_metadata
-        set_metadata(stream, mi, apply_null=self.apply_null, force_identifiers=self.force_identifiers)
+        q = self.site_customization or ''
+        set_metadata(stream, mi, apply_null=self.apply_null, force_identifiers=self.force_identifiers, add_missing_cover='disable-add-missing-cover' != q)
+
+    def customization_help(self, gui=False):
+        return _('Enter {}disable-add-missing-cover{} below to have the EPUB metadata writer plugin not'
+                 ' add cover images to EPUB files that have no existing cover image.').format(
+                     '<i>' if gui else '', '</i>' if gui else '')
 
 class FB2MetadataWriter(MetadataWriterPlugin):
 

src/calibre/customize/ui.py

@@ -383,12 +383,14 @@ def get_file_type_metadata(stream, ftype):
 def set_file_type_metadata(stream, mi, ftype, report_error=None):
     ftype = ftype.lower().strip()
     if ftype in _metadata_writers:
+        customization = config['plugin_customization']
         for plugin in _metadata_writers[ftype]:
             if not is_disabled(plugin):
                 with plugin:
                     try:
                         plugin.apply_null = apply_null_metadata.apply_null
                         plugin.force_identifiers = force_identifiers.force_identifiers
+                        plugin.site_customization = customization.get(plugin.name, '')
                         plugin.set_metadata(stream, mi, ftype.lower().strip())
                         break
                     except:

src/calibre/ebooks/metadata/epub.py

@@ -260,7 +260,7 @@ def serialize_cover_data(new_cdata, cpath):
     from calibre.utils.img import save_cover_data_to
     return save_cover_data_to(new_cdata, data_fmt=os.path.splitext(cpath)[1][1:])
 
-def set_metadata(stream, mi, apply_null=False, update_timestamp=False, force_identifiers=False):
+def set_metadata(stream, mi, apply_null=False, update_timestamp=False, force_identifiers=False, add_missing_cover=True):
     stream.seek(0)
     reader = get_zip_reader(stream, root=os.getcwdu())
     new_cdata = None
@@ -277,7 +277,8 @@ def set_metadata(stream, mi, apply_null=False, update_timestamp=False, force_ide
 
     opfbytes, ver, raster_cover = set_metadata_opf(
         reader.read_bytes(reader.opf_path), mi, cover_prefix=posixpath.dirname(reader.opf_path),
-        cover_data=new_cdata, apply_null=apply_null, update_timestamp=update_timestamp, force_identifiers=force_identifiers)
+        cover_data=new_cdata, apply_null=apply_null, update_timestamp=update_timestamp,
+        force_identifiers=force_identifiers, add_missing_cover=add_missing_cover)
     cpath = None
     replacements = {}
     if new_cdata and raster_cover:

src/calibre/ebooks/metadata/opf.py

@@ -25,7 +25,8 @@ def get_metadata(stream):
     opf = OPF(None, preparsed_opf=root, read_toc=False)
     return opf.to_book_metadata(), ver, opf.raster_cover, opf.first_spine_item()
 
-def set_metadata_opf2(root, cover_prefix, mi, opf_version, cover_data=None, apply_null=False, update_timestamp=False, force_identifiers=False):
+def set_metadata_opf2(root, cover_prefix, mi, opf_version,
+                      cover_data=None, apply_null=False, update_timestamp=False, force_identifiers=False, add_missing_cover=True):
     mi = MetaInformation(mi)
     for x in ('guide', 'toc', 'manifest', 'spine'):
         setattr(mi, x, None)
@@ -45,7 +46,7 @@ def set_metadata_opf2(root, cover_prefix, mi, opf_version, cover_data=None, appl
     if update_timestamp and mi.timestamp is not None:
         opf.timestamp = mi.timestamp
     raster_cover = opf.raster_cover
-    if raster_cover is None and cover_data is not None:
+    if raster_cover is None and cover_data is not None and add_missing_cover:
         guide_raster_cover = opf.guide_raster_cover
         i = None
         if guide_raster_cover is not None:
@@ -71,11 +72,13 @@ def set_metadata_opf2(root, cover_prefix, mi, opf_version, cover_data=None, appl
     with pretty_print:
         return opf.render(), raster_cover
 
-def set_metadata(stream, mi, cover_prefix='', cover_data=None, apply_null=False, update_timestamp=False, force_identifiers=False):
+def set_metadata(stream, mi, cover_prefix='', cover_data=None, apply_null=False, update_timestamp=False, force_identifiers=False, add_missing_cover=True):
     if isinstance(stream, bytes):
         stream = DummyFile(stream)
     root = parse_opf(stream)
     ver = parse_opf_version(root.get('version'))
     opfbytes, raster_cover = set_metadata_opf2(
-        root, cover_prefix, mi, ver, cover_data=cover_data, apply_null=apply_null, update_timestamp=update_timestamp, force_identifiers=force_identifiers)
+        root, cover_prefix, mi, ver, cover_data=cover_data,
+        apply_null=apply_null, update_timestamp=update_timestamp,
+        force_identifiers=force_identifiers, add_missing_cover=add_missing_cover)
     return opfbytes, ver, raster_cover

src/calibre/ebooks/metadata/opf3.py

@@ -196,7 +196,7 @@ def apply_metadata(root, mi, cover_prefix='', cover_data=None, apply_null=False,
     set_identifiers(root, prefixes, refines, mi.identifiers, force_identifiers=force_identifiers)
     pretty_print_opf(root)
 
-def set_metadata(stream, mi, cover_prefix='', cover_data=None, apply_null=False, update_timestamp=False, force_identifiers=False):
+def set_metadata(stream, mi, cover_prefix='', cover_data=None, apply_null=False, update_timestamp=False, force_identifiers=False, add_missing_cover=True):
     root = parse_opf(stream)
     return apply_metadata(
         root, mi, cover_prefix=cover_prefix, cover_data=cover_data,