Add compatibility shims for Python 2.7

- `os.scandir` (provided by a 3rd party package in 2.7)
- `os.replace` (doesn't exist in 2.7 - have to use `os.rename` instead)
- `os.utime` (the times param is required in 2.7)

setup.py

@@ -22,6 +22,7 @@ reqs = [
     'Pillow',
     'requests>=1.0.0',
     'mutagen>=1.33',
+    'scandir<2.0.0',
     'zipstream'
 ]
 extras = {

supysonic/cache.py

@@ -18,6 +18,8 @@ import tempfile
 import threading
 from time import time
 
+from .py23 import scandir, osreplace
+
 
 logger = logging.getLogger(__name__)
 
@@ -73,7 +75,7 @@ class Cache(object):
         self._size = 0
         self._files = OrderedDict()
         for mtime, size, key in sorted([(f.stat().st_mtime, f.stat().st_size, f.name)
-                                        for f in os.scandir(self._cache_dir)
+                                        for f in scandir(self._cache_dir)
                                         if f.is_file()]):
             self._files[key] = CacheEntry(size, mtime + self.min_time)
             self._size += size
@@ -110,7 +112,7 @@ class Cache(object):
         """Touch the file to change modified time and move it to the end of the cache dict"""
         old = self._files.pop(key)
         self._files[key] = CacheEntry(old.size, int(time()) + self.min_time)
-        os.utime(self._filepath(key))
+        os.utime(self._filepath(key), None)
 
     @property
     def size(self):
@@ -165,7 +167,7 @@ class Cache(object):
                 with self._lock:
                     if self._auto_prune:
                         self._make_space(size, key=key)
-                    os.replace(f.name, self._filename(key))
+                    osreplace(f.name, self._filepath(key))
                     self._record_file(key, size)
         except OSError as e:
             # Ignore error from trying to delete the renamed temp file

supysonic/py23.py

@@ -7,6 +7,31 @@
 #
 # Distributed under terms of the GNU AGPLv3 license.
 
+# Try built-in scandir, fall back to the package for Python 2.7
+try:
+    from os import scandir
+except ImportError:
+    from scandir import scandir
+
+# os.replace was added in Python 3.3, provide a fallback for Python 2.7
+try:
+    from os import replace as osreplace
+except ImportError:
+    # os.rename is equivalent to os.replace except on Windows
+    # On Windows an existing file will not be overwritten
+    # This fallback just attempts to delete the dst file before using rename
+    import sys
+    if sys.platform != 'win32':
+        from os import rename as osreplace
+    else:
+        import os
+        def osreplace(src, dst):
+            try:
+                os.remove(dst)
+            except OSError:
+                pass
+            os.rename(src, dst)
+
 try:
     # Python 2
     strtype = basestring