EPUB metadata: When setting metadata in an EPUB file, if it has a well defined image based cover, update it

src/calibre/ebooks/metadata/epub.py

@@ -5,7 +5,7 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 '''Read meta information from epub files'''
 
-import os, re
+import os, re, posixpath
 from cStringIO import StringIO
 from contextlib import closing
 
@@ -126,7 +126,6 @@ class OCFDirReader(OCFReader):
         return open(os.path.join(self.root, path), *args, **kwargs)
 
 def get_cover(opf, opf_path, stream, reader=None):
-    import posixpath
     from calibre.ebooks import render_html_svg_workaround
     from calibre.utils.logging import default_log
     raster_cover = opf.raster_cover
@@ -185,7 +184,37 @@ def get_quick_metadata(stream):
 def set_metadata(stream, mi, apply_null=False, update_timestamp=False):
     stream.seek(0)
     reader = OCFZipReader(stream, root=os.getcwdu())
+    raster_cover = reader.opf.raster_cover
     mi = MetaInformation(mi)
+    new_cdata = None
+    replacements = {}
+    try:
+        new_cdata = mi.cover_data[1]
+        if not new_cdata:
+            raise Exception('no cover')
+    except:
+        try:
+            new_cdata = open(mi.cover, 'rb').read()
+        except:
+            import traceback
+            traceback.print_exc()
+    if new_cdata and raster_cover:
+        try:
+            cpath = posixpath.join(posixpath.dirname(reader.opf_path),
+                    raster_cover)
+            cover_replacable = not reader.encryption_meta.is_encrypted(cpath) and \
+                    os.path.splitext(cpath)[1].lower() in ('.png', '.jpg', '.jpeg')
+            if cover_replacable:
+                from calibre.ptempfile import PersistentTemporaryFile
+                from calibre.utils.magick_draw import save_cover_data_to
+                new_cover = PersistentTemporaryFile(suffix=os.path.splitext(cpath)[1])
+                new_cover.close()
+                save_cover_data_to(new_cdata, new_cover.name)
+                replacements[cpath] = open(new_cover.name, 'rb')
+        except:
+            import traceback
+            traceback.print_exc()
+
     for x in ('guide', 'toc', 'manifest', 'spine'):
         setattr(mi, x, None)
     reader.opf.smart_update(mi)
@@ -200,5 +229,6 @@ def set_metadata(stream, mi, apply_null=False, update_timestamp=False):
         reader.opf.timestamp = mi.timestamp
 
     newopf = StringIO(reader.opf.render())
-    safe_replace(stream, reader.container[OPF.MIMETYPE], newopf)
+    safe_replace(stream, reader.container[OPF.MIMETYPE], newopf,
+            extra_replacements=replacements)
 

src/calibre/library/server/content.py

@@ -183,7 +183,8 @@ class ContentServer(object):
             fmt = TemporaryFile()
             fmt.write(raw)
             fmt.seek(0)
-            set_metadata(fmt, self.db.get_metadata(id, index_is_id=True),
+            set_metadata(fmt, self.db.get_metadata(id, index_is_id=True,
+                get_cover=True),
                     'epub')
             fmt.seek(0)
         mt = guess_type('dummy.'+format.lower())[0]

src/calibre/utils/zipfile.py

@@ -1362,7 +1362,7 @@ class ZipFile:
             self.fp.close()
         self.fp = None
 
-def safe_replace(zipstream, name, datastream):
+def safe_replace(zipstream, name, datastream, extra_replacements={}):
     '''
     Replace a file in a zip file in a safe manner. This proceeds by extracting
     and re-creating the zipfile. This is necessary because :method:`ZipFile.replace`
@@ -1371,13 +1371,19 @@ def safe_replace(zipstream, name, datastream):
     :param zipstream:  Stream from a zip file
     :param name:       The name of the file to replace
     :param datastream: The data to replace the file with.
+    :param extra_replacements: Extra replacements. Mapping of name to file-like
+                               objects
+
     '''
     z = ZipFile(zipstream, 'r')
+    replacements = {name:datastream}
+    replacements.update(extra_replacements)
+    names = frozenset(replacements.keys())
     with SpooledTemporaryFile(max_size=100*1024*1024) as temp:
         ztemp = ZipFile(temp, 'w')
         for obj in z.infolist():
-            if obj.filename == name:
-                ztemp.writestr(obj, datastream.read())
+            if obj.filename in names:
+                ztemp.writestr(obj, replacements[obj.filename].read())
             else:
                 ztemp.writestr(obj, z.read_raw(obj), raw_bytes=True)
         ztemp.close()