Adds support for already gzipped content to S3 storage

storages/backends/s3boto.py

@@ -390,15 +390,19 @@ def _save(self, name, content):
         cleaned_name = self._clean_name(name)
         name = self._normalize_name(cleaned_name)
         headers = self.headers.copy()
+        _type, encoding = mimetypes.guess_type(name)
         content_type = getattr(content, 'content_type',
-                               mimetypes.guess_type(name)[0] or self.key_class.DefaultContentType)
+                               _type or self.key_class.DefaultContentType)
 
         # setting the content_type in the key object is not enough.
         headers.update({'Content-Type': content_type})
 
         if self.gzip and content_type in self.gzip_content_types:
             content = self._compress_content(content)
             headers.update({'Content-Encoding': 'gzip'})
+        elif encoding:
+            # If the content already has a particular encoding, set it
+            headers.update({'Content-Encoding': encoding})
 
         content.name = cleaned_name
         encoded_name = self._encode_name(name)

tests/test_s3boto.py

@@ -130,6 +130,25 @@ def test_storage_save(self):
             rewind=True
         )
 
+    def test_storage_save_gzipped(self):
+        """
+        Test saving a gzipped file
+        """
+        name = 'test_storage_save.gz'
+        content = ContentFile("I am gzip'd")
+        self.storage.save(name, content)
+        key = self.storage.bucket.get_key.return_value
+        key.set_metadata.assert_called_with('Content-Type',
+                                            'application/octet-stream')
+        key.set_contents_from_file.assert_called_with(
+            content,
+            headers={'Content-Type': 'application/octet-stream',
+                     'Content-Encoding': 'gzip'},
+            policy=self.storage.default_acl,
+            reduced_redundancy=self.storage.reduced_redundancy,
+            rewind=True,
+        )
+
     def test_storage_save_gzip(self):
         """
         Test saving a file with gzip enabled.