Added support for Python 3

Author: George Schneeloch

.coveragerc

@@ -1,3 +1,4 @@
 [run]
 branch = True
-source = ./opaque_keys
+source = ./opaque_keys
+omit = ./.tox/*

AUTHORS

@@ -8,3 +8,4 @@ David Baumgold <[email protected]>
 Gabe Mulley <[email protected]>
 Braden MacDonald <[email protected]>
 Clinton Blackburn <[email protected]>
+George Schneeloch <[email protected]>

Makefile

@@ -13,4 +13,4 @@ requirements:
 	pip install -r requirements.txt
 
 test:
-	coverage run -m nose
+	tox

opaque_keys/__init__.py

@@ -10,6 +10,14 @@
 from abc import ABCMeta, abstractmethod
 from functools import total_ordering
 
+from six import (
+    iteritems,
+    python_2_unicode_compatible,
+    text_type,
+    viewkeys,
+    viewitems,
+    with_metaclass,
+)
 from stevedore.enabled import EnabledExtensionManager
 
 
@@ -34,8 +42,9 @@ def __new__(mcs, name, bases, attrs):
         return super(OpaqueKeyMetaclass, mcs).__new__(mcs, name, bases, attrs)
 
 
+@python_2_unicode_compatible
 @total_ordering
-class OpaqueKey(object):
+class OpaqueKey(with_metaclass(OpaqueKeyMetaclass)):
     """
     A base-class for implementing pluggable opaque keys. Individual key subclasses identify
     particular types of resources, without specifying the actual form of the key (or
@@ -89,7 +98,6 @@ class constructor will not validate any of the ``KEY_FIELDS`` arguments, and wil
     Serialization of an :class:`OpaqueKey` is performed by using the :func:`unicode` builtin.
     Deserialization is performed by the :meth:`from_string` method.
     """
-    __metaclass__ = OpaqueKeyMetaclass
     __slots__ = ('_initialized', 'deprecated')
 
     KEY_FIELDS = []
@@ -156,7 +164,7 @@ def _to_deprecated_string(self):
 
     # ============= SERIALIZATION ==============
 
-    def __unicode__(self):
+    def __str__(self):
         """
         Serialize this :class:`OpaqueKey`, in the form ``<CANONICAL_NAMESPACE>:<value of _to_string>``.
         """
@@ -265,13 +273,13 @@ def __init__(self, *args, **kwargs):
 
         # a flag used to indicate that this instance was deserialized from the
         # deprecated form and should serialize to the deprecated form
-        self.deprecated = kwargs.pop('deprecated', False)
+        self.deprecated = kwargs.pop('deprecated', False)  # pylint: disable=assigning-non-slot
 
         if self.CHECKED_INIT:
             self._checked_init(*args, **kwargs)
         else:
             self._unchecked_init(**kwargs)
-        self._initialized = True
+        self._initialized = True  # pylint: disable=assigning-non-slot
 
     def _checked_init(self, *args, **kwargs):
         """
@@ -285,13 +293,13 @@ def _checked_init(self, *args, **kwargs):
             ))
 
         keyed_args = dict(zip(self.KEY_FIELDS, args))
-        overlapping_args = keyed_args.viewkeys() & kwargs.viewkeys()
+        overlapping_args = viewkeys(keyed_args) & viewkeys(kwargs)
         if overlapping_args:
             raise TypeError('__init__() got multiple values for keyword argument {!r}'.format(overlapping_args[0]))
 
         keyed_args.update(kwargs)
 
-        for key in keyed_args.viewkeys():
+        for key in viewkeys(keyed_args):
             if key not in self.KEY_FIELDS:
                 raise TypeError('__init__() got an unexpected argument {!r}'.format(key))
 
@@ -301,7 +309,7 @@ def _unchecked_init(self, **kwargs):
         """
         Set all kwargs as attributes.
         """
-        for key, value in kwargs.viewitems():
+        for key, value in viewitems(kwargs):
             setattr(self, key, value)
 
     def replace(self, **kwargs):
@@ -315,7 +323,7 @@ def replace(self, **kwargs):
         existing_values = {key: getattr(self, key) for key in self.KEY_FIELDS}  # pylint: disable=no-member
         existing_values['deprecated'] = self.deprecated
 
-        if all(value == existing_values[key] for (key, value) in kwargs.iteritems()):
+        if all(value == existing_values[key] for (key, value) in iteritems(kwargs)):
             return self
 
         existing_values.update(kwargs)
@@ -325,7 +333,7 @@ def __setattr__(self, name, value):
         if getattr(self, '_initialized', False):
             raise AttributeError("Can't set {!r}. OpaqueKeys are immutable.".format(name))
 
-        super(OpaqueKey, self).__setattr__(name, value)
+        super(OpaqueKey, self).__setattr__(name, value)  # pylint: disable=no-member
 
     def __delattr__(self, name):
         raise AttributeError("Can't delete {!r}. OpaqueKeys are immutable.".format(name))
@@ -348,8 +356,8 @@ def __setstate__(self, state_dict):
         for key in state_dict:
             if key in self.KEY_FIELDS:  # pylint: disable=no-member
                 setattr(self, key, state_dict[key])
-        self.deprecated = state_dict['deprecated']
-        self._initialized = True
+        self.deprecated = state_dict['deprecated']  # pylint: disable=assigning-non-slot
+        self._initialized = True  # pylint: disable=assigning-non-slot
 
     def __getstate__(self):
         # used by pickle to get fields on an unpickled object
@@ -380,9 +388,6 @@ def __lt__(self, other):
     def __hash__(self):
         return hash(self._key)
 
-    def __str__(self):
-        return unicode(self).encode('utf-8')
-
     def __repr__(self):
         return '{}({})'.format(
             self.__class__.__name__,
@@ -391,4 +396,4 @@ def __repr__(self):
 
     def __len__(self):
         """Return the number of characters in the serialized OpaqueKey"""
-        return len(unicode(self))
+        return len(text_type(self))

opaque_keys/edx/asides.py

@@ -12,6 +12,7 @@
 store scoped data alongside the definition and usage of the particular XBlock usage that they're
 commenting on.
 """
+from six import text_type
 
 from opaque_keys.edx.keys import AsideDefinitionKey, AsideUsageKey, DefinitionKey, UsageKey
 
@@ -90,7 +91,7 @@ def _to_string(self):
 
         This serialization should not include the namespace prefix.
         """
-        return u'{}::{}'.format(_encode(unicode(self.definition_key)), _encode(unicode(self.aside_type)))
+        return u'{}::{}'.format(_encode(text_type(self.definition_key)), _encode(text_type(self.aside_type)))
 
 
 class AsideUsageKeyV1(AsideUsageKey):  # pylint: disable=abstract-method
@@ -179,4 +180,4 @@ def _to_string(self):
 
         This serialization should not include the namespace prefix.
         """
-        return u'{}::{}'.format(_encode(unicode(self.usage_key)), _encode(unicode(self.aside_type)))
+        return u'{}::{}'.format(_encode(text_type(self.usage_key)), _encode(text_type(self.aside_type)))

opaque_keys/edx/keys.py

@@ -4,6 +4,7 @@
 """
 import json
 from abc import abstractmethod, abstractproperty
+from six import text_type
 
 from opaque_keys import OpaqueKey
 
@@ -207,7 +208,7 @@ class i4xEncoder(json.JSONEncoder):  # pylint: disable=invalid-name
     """
     def default(self, key):  # pylint: disable=method-hidden
         if isinstance(key, OpaqueKey):
-            return unicode(key)
+            return text_type(key)
         super(i4xEncoder, self).default(key)
 
 

opaque_keys/edx/locator.py

@@ -9,6 +9,7 @@
 import re
 import warnings
 from abc import abstractproperty
+from six import string_types, text_type
 
 from bson.errors import InvalidId
 from bson.objectid import ObjectId
@@ -45,12 +46,6 @@ class Locator(OpaqueKey):
     ALLOWED_ID_CHARS = r'[\w\-~.:]'
     DEPRECATED_ALLOWED_ID_CHARS = r'[\w\-~.:%]'
 
-    def __str__(self):
-        """
-        str(self) returns something like this: "mit.eecs.6002x"
-        """
-        return unicode(self).encode('utf-8')
-
     @abstractproperty
     def version(self):  # pragma: no cover
         """
@@ -159,9 +154,6 @@ class CourseLocator(BlockLocatorBase, CourseKey):   # pylint: disable=abstract-m
     # Characters that are forbidden in the deprecated format
     INVALID_CHARS_DEPRECATED = re.compile(r"[^\w.%-]", re.UNICODE)
 
-    # stubs to fake out the abstractproperty class instrospection and allow treatment as attrs in instances
-    org = None
-
     def __init__(self, org=None, course=None, run=None, branch=None, version_guid=None, deprecated=False, **kwargs):
         """
         Construct a CourseLocator
@@ -223,7 +215,7 @@ def __init__(self, org=None, course=None, run=None, branch=None, version_guid=No
     def _check_location_part(cls, val, regexp):  # pylint: disable=missing-docstring
         if val is None:
             return
-        if not isinstance(val, basestring):
+        if not isinstance(val, string_types):
             raise InvalidKeyError(cls, "{!r} is not a string".format(val))
         if regexp.search(val) is not None:
             raise InvalidKeyError(cls, "Invalid characters in {!r}.".format(val))
@@ -278,7 +270,7 @@ def html_id(self):
         place, but I have no way to override. We should clearly define the purpose and restrictions of this
         (e.g., I'm assuming periods are fine).
         """
-        return unicode(self)
+        return text_type(self)
 
     def make_usage_key(self, block_type, block_id):
         return BlockUsageLocator(
@@ -367,7 +359,7 @@ def to_deprecated_string(self):
             DeprecationWarning,
             stacklevel=2
         )
-        return unicode(self)
+        return text_type(self)
 
     @classmethod
     def _from_deprecated_string(cls, serialized):
@@ -421,12 +413,6 @@ class LibraryLocator(BlockLocatorBase, CourseKey):
     __slots__ = KEY_FIELDS
     CHECKED_INIT = False
 
-    # declare our fields explicitly to avoid pylint warnings
-    org = None
-    library = None
-    branch = None
-    version_guid = None
-
     def __init__(self, org=None, library=None, branch=None, version_guid=None, **kwargs):
         """
         Construct a LibraryLocator
@@ -472,7 +458,7 @@ def __init__(self, org=None, library=None, branch=None, version_guid=None, **kwa
             **kwargs
         )
 
-        if self.version_guid is None and (self.org is None or self.library is None):
+        if self.version_guid is None and (self.org is None or self.library is None):  # pylint: disable=no-member
             raise InvalidKeyError(self.__class__, "Either version_guid or org and library should be set")
 
     @property
@@ -489,7 +475,7 @@ def course(self):
         Deprecated. Return a 'course' for compatibility with CourseLocator.
         """
         warnings.warn("Accessing 'course' on a LibraryLocator is deprecated.", DeprecationWarning, stacklevel=2)
-        return self.library
+        return self.library  # pylint: disable=no-member
 
     @property
     def version(self):
@@ -502,7 +488,7 @@ def version(self):
             DeprecationWarning,
             stacklevel=2
         )
-        return self.version_guid
+        return self.version_guid  # pylint: disable=no-member
 
     @classmethod
     def _from_string(cls, serialized):
@@ -526,7 +512,7 @@ def html_id(self):
         """
         Return an id which can be used on an html page as an id attr of an html element.
         """
-        return unicode(self)
+        return text_type(self)
 
     def make_usage_key(self, block_type, block_id):
         return LibraryUsageLocator(
@@ -579,12 +565,12 @@ def _to_string(self):
         Return a string representing this location.
         """
         parts = []
-        if self.library:
+        if self.library:  # pylint: disable=no-member
             parts.extend([self.org, self.course])
-            if self.branch:
-                parts.append(u"{prefix}@{branch}".format(prefix=self.BRANCH_PREFIX, branch=self.branch))
-        if self.version_guid:
-            parts.append(u"{prefix}@{guid}".format(prefix=self.VERSION_PREFIX, guid=self.version_guid))
+            if self.branch:  # pylint: disable=no-member
+                parts.append(u"{prefix}@{branch}".format(prefix=self.BRANCH_PREFIX, branch=self.branch))  # pylint: disable=no-member
+        if self.version_guid:  # pylint: disable=no-member
+            parts.append(u"{prefix}@{guid}".format(prefix=self.VERSION_PREFIX, guid=self.version_guid))  # pylint: disable=no-member
         return u"+".join(parts)
 
     def _to_deprecated_string(self):
@@ -977,7 +963,7 @@ def to_deprecated_string(self):
             DeprecationWarning,
             stacklevel=2
         )
-        return unicode(self)
+        return text_type(self)
 
     @classmethod
     def _from_deprecated_string(cls, serialized):
@@ -1176,7 +1162,7 @@ class DefinitionLocator(Locator, DefinitionKey):
     definition_id = None
 
     def __init__(self, block_type, definition_id, deprecated=False):    # pylint: disable=unused-argument
-        if isinstance(definition_id, basestring):
+        if isinstance(definition_id, string_types):
             try:
                 definition_id = self.as_object_id(definition_id)
             except ValueError:
@@ -1188,7 +1174,7 @@ def _to_string(self):
         Return a string representing this location.
         unicode(self) returns something like this: "519665f6223ebd6980884f2b+type+problem"
         """
-        return u"{}+{}@{}".format(unicode(self.definition_id), self.BLOCK_TYPE_PREFIX, self.block_type)
+        return u"{}+{}@{}".format(text_type(self.definition_id), self.BLOCK_TYPE_PREFIX, self.block_type)
 
     URL_RE = re.compile(
         r"^(?P<definition_id>[A-F0-9]+)\+{}@(?P<block_type>{ALLOWED_ID_CHARS}+)$".format(
@@ -1298,7 +1284,7 @@ def to_deprecated_string(self):
             DeprecationWarning,
             stacklevel=2
         )
-        return unicode(self)
+        return text_type(self)
 
     @property
     def tag(self):

opaque_keys/edx/tests/__init__.py

@@ -26,8 +26,8 @@ def assertDeprecationWarning(self, count=1):
         """Asserts that the contained code raises `count` deprecation warnings"""
         with warnings.catch_warnings(record=True) as caught:
             yield
-        self.assertEquals(count,
-                          len([warning for warning in caught if issubclass(warning.category, DeprecationWarning)]))
+        self.assertEqual(count,
+                         len([warning for warning in caught if issubclass(warning.category, DeprecationWarning)]))
 
 
 class LocatorBaseTest(TestCase):