Fixed #36293 -- Avoided buffering streaming responses in GZipMiddleware.

This avoids latency and/or blocking.

The example of streaming a CSV file was rewritten to employ batching for
greater efficiency in all layers (db, HTTP, etc.). The improved
performance from batching should outweigh the drag introduced by an
additional byte for each flush.

Co-authored-by: huoyinghui <huoyinghui@users.noreply.github.com>

1 files changed, 31 insertions, 1 deletions

diff --git a/tests/decorators/test_gzip.py b/tests/decorators/test_gzip.py
index 2d64c171f7..8cd0869b53 100644
--- a/tests/decorators/test_gzip.py
+++ b/tests/decorators/test_gzip.py
@@ -1,6 +1,6 @@
 from inspect import iscoroutinefunction
 
-from django.http import HttpRequest, HttpResponse
+from django.http import HttpRequest, HttpResponse, StreamingHttpResponse
 from django.test import SimpleTestCase
 from django.views.decorators.gzip import gzip_page
 
@@ -44,3 +44,33 @@ class GzipPageTests(SimpleTestCase):
         response = await async_view(request)
         self.assertEqual(response.status_code, 200)
         self.assertEqual(response.get("Content-Encoding"), "gzip")
+
+    def test_streaming_response_yields_chunks_incrementally(self):
+        @gzip_page
+        def stream_view(request):
+            return StreamingHttpResponse(self.content.encode() for _ in range(5))
+
+        request = HttpRequest()
+        request.META["HTTP_ACCEPT_ENCODING"] = "gzip"
+        response = stream_view(request)
+        compressed_chunks = list(response)
+        # Each input chunk should produce compressed output, not buffer
+        # everything into a single chunk.
+        self.assertGreater(len(compressed_chunks), 2)
+
+    async def test_async_streaming_response_yields_chunks_incrementally(self):
+        @gzip_page
+        async def stream_view(request):
+            async def content():
+                for _ in range(5):
+                    yield self.content.encode()
+
+            return StreamingHttpResponse(content())
+
+        request = HttpRequest()
+        request.META["HTTP_ACCEPT_ENCODING"] = "gzip"
+        response = await stream_view(request)
+        compressed_chunks = [chunk async for chunk in response]
+        # Each input chunk should produce compressed output, not buffer
+        # everything into a single chunk.
+        self.assertGreater(len(compressed_chunks), 2)