Check responses when retrying bodies

Previously, if a Range request came back 200 OK (rather than 206 Partial
Content), we would mangle the response body. This could happen if there
was a middleware that would silently drop Range headers, for example.

Now, if the response does not include a Content-Range header, we will
log a warning and seek to our previous position in the stream. If the
Content-Range header has an unexpected value, we will raise an exception.

Change-Id: I94d4536cc1489968d45a2b6ba7edd70c85800275

1 files changed, 17 insertions, 0 deletions

diff --git a/swiftclient/client.py b/swiftclient/client.py
index a5c4dc3..6990ea3 100644
--- a/swiftclient/client.py
+++ b/swiftclient/client.py
@@ -249,6 +249,23 @@ class _RetryBody(_ObjectBody):
                                           response_dict=self.response_dict,
                                           headers=self.headers,
                                           attempts=self.conn.attempts)
+            expected_range = 'bytes %d-%d/%d' % (
+                self.bytes_read,
+                self.expected_length - 1,
+                self.expected_length)
+            if 'content-range' not in hdrs:
+                # Server didn't respond with partial content; manually seek
+                logger.warning('Received 200 while retrying %s/%s; seeking...',
+                               self.container, self.obj)
+                to_read = self.bytes_read
+                while to_read > 0:
+                    buf = body.resp.read(min(to_read, self.chunk_size))
+                    to_read -= len(buf)
+            elif hdrs['content-range'] != expected_range:
+                msg = ('Expected range "%s" while retrying %s/%s '
+                       'but got "%s"' % (expected_range, self.container,
+                                         self.obj, hdrs['content-range']))
+                raise ClientException(msg)
             self.resp = body.resp
             buf = self.read(length)
         return buf