Drop Python 2 support and Django 1.8/1.9 support

private_storage/fields.py

 #-*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
 import datetime
 import logging
 import os
@@ -23,12 +21,6 @@ from .storage import private_storage
 logger = logging.getLogger(__name__)
 
 
-try:
-    string_types = basestring,  # Python 2
-except NameError:
-    string_types = str,  # Python 3
-
-
 class PrivateFileField(models.FileField):
     """
     Filefield with private storage, custom filename and size checks.
@@ -90,7 +82,7 @@ class PrivateFileField(models.FileField):
             extra_dirs = upload_subfolder(instance)
 
             # Avoid mistakes by developers, no "s/u/b/p/a/t/h/"
-            if isinstance(extra_dirs, string_types):
+            if isinstance(extra_dirs, str):
                 warnings.warn("{}.{}.upload_subfolder should return a list"
                               " to avoid path-separator issues.".format(
                     instance.__class__.__name__, self.name), UserWarning)

private_storage/servers.py

@@ -4,7 +4,8 @@ Sending files efficiently for different kind of webservers.
 import os
 import sys
 import time
-from functools import wraps
+from functools import lru_cache, wraps
+from urllib.parse import quote
 
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
@@ -13,15 +14,6 @@ from django.utils.http import http_date
 from django.utils.module_loading import import_string
 from django.views.static import serve, was_modified_since
 
-try:
-    # python 3
-    from urllib.parse import quote
-    from functools import lru_cache  # Python 3
-except ImportError:
-    # python 2
-    from urllib import quote
-    from django.utils.lru_cache import lru_cache  # Django <3
-
 
 @lru_cache()
 def get_server_class(path):

private_storage/storage/files.py

@@ -2,16 +2,12 @@
 Django Storage interface, using the file system backend.
 """
 from django.core.files.storage import FileSystemStorage
+from django.urls import reverse_lazy
 from django.utils.deconstruct import deconstructible
 from django.utils.encoding import force_text
 
 from private_storage import appconfig
 
-try:
-    from django.urls import reverse_lazy  # Added in Django 1.10
-except ImportError:
-    from django.core.urlresolvers import reverse_lazy
-
 
 @deconstructible
 class PrivateFileSystemStorage(FileSystemStorage):

private_storage/views.py

@@ -2,6 +2,7 @@
 Views to send private files.
 """
 import os
+from urllib.parse import quote
 
 from django.http import Http404
 from django.utils.module_loading import import_string
@@ -14,11 +15,6 @@ from .models import PrivateFile
 from .servers import get_server_class
 from .storage import private_storage
 
-try:
-    from urllib.parse import quote
-except ImportError:
-    from urllib import quote  # Python 2
-
 
 class PrivateStorageView(View):
     """

runtests.py

@@ -41,6 +41,7 @@ if not settings.configured:
                 },
             },
         ],
+        DEFAULT_AUTO_FIELD='django.db.models.BigAutoField',
         AWS_PRIVATE_STORAGE_BUCKET_NAME='foobar',
         PRIVATE_STORAGE_ROOT=path.join(module_root, 'test-media-root'),
     )