[sftp] Check full path for existence in ._save() and ._mkdir() (#1372)

storages/backends/sftpstorage.py

@@ -118,7 +118,7 @@ def _mkdir(self, path):
         """Create directory, recursing up to create parent dirs if
         necessary."""
         parent = posixpath.dirname(path)
-        if not self.exists(parent):
+        if not self._path_exists(parent):
             self._mkdir(parent)
         self.sftp.mkdir(path)
 
@@ -134,7 +134,7 @@ def _save(self, name, content):
             content.seek(0, os.SEEK_SET)
         path = self._remote_path(name)
         dirname = posixpath.dirname(path)
-        if not self.exists(dirname):
+        if not self._path_exists(dirname):
             self._mkdir(dirname)
 
         self.sftp.putfo(content, path)
@@ -152,13 +152,23 @@ def delete(self, name):
         except OSError:
             pass
 
-    def exists(self, name):
+    def _path_exists(self, path):
+        """Determines whether a file existis in the sftp storage given its
+        absolute path."""
         try:
-            self.sftp.stat(self._remote_path(name))
+            self.sftp.stat(path)
             return True
         except FileNotFoundError:
             return False
 
+    def exists(self, name):
+        """Determines whether a file exists within the root folder of the SFTP storage
+        (as set by `SFTP_STORAGE_ROOT`). This method differs from `._path_exists()`
+        in that the provided `name` is assumed to be the relative path of the file
+        within the root folder.
+        """
+        return self._path_exists(self._remote_path(name))
+
     def _isdir_attr(self, item):
         # Return whether an item in sftp.listdir_attr results is a directory
         if item.st_mode is not None:

tests/test_sftp.py

@@ -16,7 +16,7 @@
 
 class SFTPStorageTest(TestCase):
     def setUp(self):
-        self.storage = sftpstorage.SFTPStorage(host="foo")
+        self.storage = sftpstorage.SFTPStorage(host="foo", root_path="root")
 
     def test_init(self):
         pass
@@ -95,13 +95,18 @@ def test_save_non_seekable(self, mock_sftp):
     )
     def test_save_in_subdir(self, mock_sftp):
         self.storage._save("bar/foo", File(io.BytesIO(b"foo"), "foo"))
-        self.assertEqual(mock_sftp.mkdir.call_args_list[0][0], ("bar",))
+        self.assertEqual(mock_sftp.stat.call_args_list[0][0], ("root/bar",))
+        self.assertEqual(mock_sftp.mkdir.call_args_list[0][0], ("root/bar",))
         self.assertTrue(mock_sftp.putfo.called)
 
     @patch("storages.backends.sftpstorage.SFTPStorage.sftp")
     def test_delete(self, mock_sftp):
         self.storage.delete("foo")
-        self.assertEqual(mock_sftp.remove.call_args_list[0][0], ("foo",))
+        self.assertEqual(mock_sftp.remove.call_args_list[0][0], ("root/foo",))
+
+    @patch("storages.backends.sftpstorage.SFTPStorage.sftp")
+    def test_path_exists(self, mock_sftp):
+        self.assertTrue(self.storage._path_exists("root/foo"))
 
     @patch("storages.backends.sftpstorage.SFTPStorage.sftp")
     def test_exists(self, mock_sftp):
@@ -114,6 +119,13 @@ def test_exists(self, mock_sftp):
     def test_not_exists(self, mock_sftp):
         self.assertFalse(self.storage.exists("foo"))
 
+    @patch(
+        "storages.backends.sftpstorage.SFTPStorage.sftp",
+        **{"stat.side_effect": FileNotFoundError()},
+    )
+    def test_not_path_exists(self, mock_sftp):
+        self.assertFalse(self.storage._path_exists("root/foo"))
+
     @patch(
         "storages.backends.sftpstorage.SFTPStorage.sftp",
         **{"stat.side_effect": socket.timeout()},