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/adobekey.py

@@ -48,14 +48,16 @@ from __future__ import with_statement
 #   5.8 - Added getkey interface for Windows DeDRM application
 #   5.9 - moved unicode_argv call inside main for Windows DeDRM compatibility
 #   6.0 - Work if TkInter is missing
+#   7.0 - Python 3 compatible for calibre 5
+
+from __future__ import print_function
 
 """
 Retrieve Adobe ADEPT user key.
 """
-from __future__ import print_function
 
 __license__ = 'GPL v3'
-__version__ = '6.0'
+__version__ = '7.0'
 
 import sys, os, struct, getopt
 
@@ -118,7 +120,7 @@ def unicode_argv():
         argvencoding = sys.stdin.encoding
         if argvencoding == None:
             argvencoding = "utf-8"
-        return [arg if (type(arg) == unicode) else unicode(arg,argvencoding) for arg in sys.argv]
+        return arg
 
 class ADEPTError(Exception):
     pass
@@ -497,7 +499,7 @@ def cli_main():
 
     try:
         opts, args = getopt.getopt(argv[1:], "h")
-    except getopt.GetoptError, err:
+    except getopt.GetoptError as err:
         print(u"Error in options or arguments: {0}".format(err.args[0]))
         usage(progname)
         sys.exit(2)
@@ -586,7 +588,7 @@ def gui_main():
                 keyfileout.write(key)
             success = True
             tkMessageBox.showinfo(progname, u"Key successfully retrieved to {0}".format(outfile))
-    except ADEPTError, e:
+    except ADEPTError as e:
         tkMessageBox.showerror(progname, u"Error: {0}".format(str(e)))
     except Exception:
         root.wm_state('normal')