Fixed #33735 -- Added async support to StreamingHttpResponse.

Thanks to Florian Vazelle for initial exploratory work, and to Nick
Pope and Mariusz Felisiak for review.

1 files changed, 18 insertions, 4 deletions

diff --git a/django/middleware/gzip.py b/django/middleware/gzip.py
index d91246c007..45be6ccb43 100644
--- a/django/middleware/gzip.py
+++ b/django/middleware/gzip.py
@@ -31,12 +31,26 @@ class GZipMiddleware(MiddlewareMixin):
             return response
 
         if response.streaming:
+            if response.is_async:
+                # pull to lexical scope to capture fixed reference in case
+                # streaming_content is set again later.
+                orignal_iterator = response.streaming_content
+
+                async def gzip_wrapper():
+                    async for chunk in orignal_iterator:
+                        yield compress_string(
+                            chunk,
+                            max_random_bytes=self.max_random_bytes,
+                        )
+
+                response.streaming_content = gzip_wrapper()
+            else:
+                response.streaming_content = compress_sequence(
+                    response.streaming_content,
+                    max_random_bytes=self.max_random_bytes,
+                )
             # Delete the `Content-Length` header for streaming content, because
             # we won't know the compressed size until we stream it.
-            response.streaming_content = compress_sequence(
-                response.streaming_content,
-                max_random_bytes=self.max_random_bytes,
-            )
             del response.headers["Content-Length"]
         else:
             # Return the compressed content only if it's actually shorter.