Replace unicode with str, duck type encode

dataset/freeze/config.py

@@ -1,6 +1,11 @@
 import json
 import yaml
 
+try:
+    str = unicode
+except NameError:
+    pass
+
 from dataset.util import FreezeException
 
 
@@ -35,7 +40,7 @@ class Configuration(object):
                 raise FreezeException("Invalid freeze file: %s" % ve)
             fh.close()
         except IOError as ioe:
-            raise FreezeException(unicode(ioe))
+            raise FreezeException(str(ioe))
 
     @property
     def exports(self):
@@ -59,7 +64,7 @@ class Export(object):
     def get_normalized(self, name, default=None):
         value = self.get(name, default=default)
         if not value in [None, default]:
-            value = unicode(value).lower().strip()
+            value = str(value).lower().strip()
         return value
 
     def get_bool(self, name, default=False):

dataset/freeze/format/common.py

@@ -3,6 +3,11 @@ import logging
 import re
 import locale
 
+try:
+    str = unicode
+except NameError:
+    pass
+
 from dataset.util import FreezeException
 from slugify import slugify
 
@@ -11,7 +16,7 @@ TMPL_KEY = re.compile("{{([^}]*)}}")
 
 OPERATIONS = {
         'identity': lambda x: x,
-        'lower': lambda x: unicode(x).lower(),
+        'lower': lambda x: str(x).lower(),
         'slug': slugify
         }
 
@@ -39,7 +44,7 @@ class Serializer(object):
             op, key = 'identity', m.group(1)
             if ':' in key:
                 op, key = key.split(':', 1)
-            return unicode(OPERATIONS.get(op)(data.get(key, '')))
+            return str(OPERATIONS.get(op)(data.get(key, '')))
         path = TMPL_KEY.sub(repl, self._basepath)
         enc = locale.getpreferredencoding()
         return os.path.realpath(path.encode(enc, 'replace'))
@@ -74,8 +79,6 @@ class Serializer(object):
 
             for field, operation in transforms.items():
                 row[field] = OPERATIONS.get(operation)(row.get(field))
-            
+
             self.write(self.file_name(row), row)
         self.close()
-
-

dataset/freeze/format/fcsv.py

@@ -7,7 +7,7 @@ from dataset.freeze.format.common import Serializer
 def value_to_str(value):
     if isinstance(value, datetime):
         return value.isoformat()
-    if isinstance(value, unicode):
+    if hasattr(value, 'encode'):
         return value.encode('utf-8')
     if value is None:
         return ''