Starting on Version 7.0 using the work done by others. Completely untested. I will be testing things, but I thought I'd get this base version up for others to give pull requests.

THIS IS ON THE MASTER BRANCH. The Master branch will be Python 3.0 from now on. While Python 2.7 support will not be deliberately broken, all efforts should now focus on Python 3.0 compatibility.

I can see a lot of work has been done. There's more to do. I've bumped the version number of everything I came across to the next major number for Python 3.0 compatibility indication.

Thanks everyone. I hope to update here at least once a week until we have a stable 7.0 release for calibre 5.0

DeDRM_plugin/zipfix.py

@@ -1,8 +1,8 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
-# zipfix.py, version 1.1
-# Copyright © 2010-2013 by some_updates, DiapDealer and Apprentice Alf
+# zipfix.py
+# Copyright © 2010-2020 by some_updates, DiapDealer and Apprentice Alf
 
 # Released under the terms of the GNU General Public Licence, version 3
 # <http://www.gnu.org/licenses/>
@@ -10,6 +10,7 @@
 # Revision history:
 #   1.0 - Initial release
 #   1.1 - Updated to handle zip file metadata correctly
+#   2.0 - Added Python 3 compatibility for calibre 5.0
 
 """
 Re-write zip (or ePub) fixing problems with file names (and mimetype entry).
@@ -21,7 +22,7 @@ __version__ = "1.1"
 
 import sys
 import zlib
-import zipfilerugged
+import calibre_plugins.dedrm.zipfilerugged as zipfilerugged
 import os
 import os.path
 import getopt
@@ -49,7 +50,7 @@ class fixZip:
         self.inzip = zipfilerugged.ZipFile(zinput,'r')
         self.outzip = zipfilerugged.ZipFile(zoutput,'w')
         # open the input zip for reading only as a raw file
-        self.bzf = file(zinput,'rb')
+        self.bzf = open(zinput,'rb')
 
     def getlocalname(self, zi):
         local_header_offset = zi.header_offset
@@ -115,7 +116,7 @@ class fixZip:
         # if epub write mimetype file first, with no compression
         if self.ztype == 'epub':
             # first get a ZipInfo with current time and no compression
-            mimeinfo = ZipInfo('mimetype',compress_type=zipfilerugged.ZIP_STORED)
+            mimeinfo = ZipInfo(b'mimetype',compress_type=zipfilerugged.ZIP_STORED)
             mimeinfo.internal_attr = 1 # text file
             try:
                 # if the mimetype is present, get its info, including time-stamp
@@ -129,7 +130,7 @@ class fixZip:
                 mimeinfo.create_system = oldmimeinfo.create_system
             except:
                 pass
-            self.outzip.writestr(mimeinfo, _MIMETYPE)
+            self.outzip.writestr(mimeinfo, _MIMETYPE.encode('ascii'))
 
         # write the rest of the files
         for zinfo in self.inzip.infolist():
@@ -171,7 +172,7 @@ def repairBook(infile, outfile):
         fr = fixZip(infile, outfile)
         fr.fix()
         return 0
-    except Exception, e:
+    except Exception as e:
         print("Error Occurred ", e)
         return 2