ChunkBasedFileResponse: Support Content-Length

src/pretix/helpers/http.py

@@ -5,5 +5,7 @@ class ChunkBasedFileResponse(StreamingHttpResponse):
     block_size = 4096
 
     def __init__(self, streaming_content=(), *args, **kwargs):
+        filelike = streaming_content
         streaming_content = streaming_content.chunks(self.block_size)
         super().__init__(streaming_content, *args, **kwargs)
+        self['Content-Length'] = filelike.size