Fix unicode parsing error with Python 3 (#85)

* Fix unicode parsing error with Python 3

CHANGES.rst

@@ -4,6 +4,9 @@ Changelog
 4.3.3 (unreleased)
 ------------------
 
+- Fix unicode parsing error on Python 3, resulting in empty mosaic page (`#62 https://github.com/plone/plone.app.mosaic/issues/480`_).
+  [agitator]
+
 - Update test setup 
   [ksuess]
 

plone/app/blocks/transform.py

@@ -11,9 +11,13 @@
 from repoze.xmliter.utils import getHTMLSerializer
 from zope.interface import implementer
 
+import six
 import re
+import logging
 
 
+logger = logging.getLogger(__name__)
+
 @implementer(ITransform)
 class DisableParsing(object):
     """A no-op transform which sets flags to stop plone.app.blocks
@@ -85,19 +89,31 @@ def transformIterable(self, result, encoding):
         try:
             # Fix layouts with CR[+LF] line endings not to lose their heads
             # (this has been seen with downloaded themes with CR[+LF] endings)
-            iterable = [
-                re.sub('
', '\n', re.sub('
\n', '\n', safe_unicode(item)))  # noqa
-                for item in result if item]
-            result = getHTMLSerializer(
-                iterable, pretty_print=self.pretty_print, encoding=encoding)
-            # Fix XHTML layouts with where etree.tostring breaks <![CDATA[
-            if any(['<![CDATA[' in item for item in iterable]):
-                result.serializer = html.tostring
+
+            if six.PY2:
+                iterable = [
+                    re.sub('&#13;', '\n', re.sub('&#13;\n', '\n', safe_unicode(item)))  # noqa
+                    for item in result if item]
+                result = getHTMLSerializer(
+                    iterable, pretty_print=self.pretty_print, encoding=encoding)
+                # Fix XHTML layouts with where etree.tostring breaks <![CDATA[
+                if any(['<![CDATA[' in item for item in iterable]):
+                    result.serializer = html.tostring                
+            else:
+                iterable = [
+                    re.sub('&#13;'.encode('utf-8'), '\n'.encode('utf-8'), re.sub('&#13;\n'.encode('utf-8'), '\n'.encode('utf-8'), item))  # noqa
+                    for item in result if item]
+                result = getHTMLSerializer(
+                    iterable, pretty_print=self.pretty_print, encoding=encoding)
+                # Fix XHTML layouts with where etree.tostring breaks <![CDATA[
+                if any([b'<![CDATA[' in item for item in iterable]):
+                    result.serializer = html.tostring
+
             self.request['plone.app.blocks.enabled'] = True
             return result
-        except (AttributeError, TypeError, etree.ParseError):
-            return None
-
+        except (AttributeError, TypeError, etree.ParseError) as e:
+             logger.error(e)
+             return None
 
 @implementer(ITransform)
 class MergePanels(object):