Fix: correct text/stream compression workaround (#14064)

src/paperless/tests/test_compression_middleware.py

@@ -0,0 +1,54 @@
+from django.http import HttpResponse
+from django.http import StreamingHttpResponse
+from django.test import RequestFactory
+from django.test import TestCase
+
+from paperless.middleware import StreamAwareCompressionMiddleware
+
+
+class TestStreamAwareCompressionMiddleware(TestCase):
+    def setUp(self) -> None:
+        super().setUp()
+        self.factory = RequestFactory()
+        self.middleware = StreamAwareCompressionMiddleware(lambda request: None)
+
+    def _request(self):
+        return self.factory.get(
+            "/api/documents/chat/",
+            HTTP_ACCEPT_ENCODING="gzip, deflate, br, zstd",
+        )
+
+    def test_event_stream_is_not_compressed(self) -> None:
+        """
+        GIVEN:
+            - A server-sent event response produced chunk by chunk
+        WHEN:
+            - The compression middleware processes it
+        THEN:
+            - It is passed through unencoded, one wire chunk per source chunk
+        """
+        chunks = [f"token{i} ".encode() for i in range(40)]
+        response = StreamingHttpResponse(
+            iter(chunks),
+            content_type="text/event-stream",
+        )
+
+        response = self.middleware.process_response(self._request(), response)
+
+        assert not response.has_header("Content-Encoding")
+        assert list(response.streaming_content) == chunks
+
+    def test_regular_response_is_still_compressed(self) -> None:
+        """
+        GIVEN:
+            - An ordinary response large enough to be worth compressing
+        WHEN:
+            - The compression middleware processes it
+        THEN:
+            - It is compressed as before
+        """
+        response = HttpResponse(b"a" * 5000, content_type="application/json")
+
+        response = self.middleware.process_response(self._request(), response)
+
+        assert response.has_header("Content-Encoding")