Backport stream header fix (#1959)

Resolve headers as body in ASGI mode

* Bump version to 19.12.3

* Update multidict==5.0.0

sanic/__version__.py

@@ -1 +1 @@
-__version__ = "19.12.2"
+__version__ = "19.12.3"

sanic/asgi.py

@@ -347,6 +347,8 @@ class ASGIApp:
                 if name not in (b"Set-Cookie",)
             ]
 
+        response.asgi = True
+
         if "content-length" not in response.headers and not isinstance(
             response, StreamingHTTPResponse
         ):

sanic/response.py

@@ -22,6 +22,9 @@ except ImportError:
 
 
 class BaseHTTPResponse:
+    def __init__(self):
+        self.asgi = False
+
     def _encode_body(self, data):
         try:
             # Try to encode it regularly
@@ -59,6 +62,8 @@ class StreamingHTTPResponse(BaseHTTPResponse):
         content_type="text/plain",
         chunked=True,
     ):
+        super().__init__()
+
         self.content_type = content_type
         self.streaming_fn = streaming_fn
         self.status = status
@@ -94,6 +99,7 @@ class StreamingHTTPResponse(BaseHTTPResponse):
             keep_alive=keep_alive,
             keep_alive_timeout=keep_alive_timeout,
         )
+        if not getattr(self, "asgi", False):
             await self.protocol.push_data(headers)
             await self.protocol.drain()
         await self.streaming_fn(self)
@@ -145,6 +151,8 @@ class HTTPResponse(BaseHTTPResponse):
         content_type=None,
         body_bytes=b"",
     ):
+        super().__init__()
+
         self.content_type = content_type
 
         if body is not None:

setup.py

@@ -5,7 +5,6 @@ import codecs
 import os
 import re
 import sys
-
 from distutils.util import strtobool
 
 from setuptools import setup
@@ -39,9 +38,7 @@ def open_local(paths, mode="r", encoding="utf8"):
 
 with open_local(["sanic", "__version__.py"], encoding="latin1") as fp:
     try:
-        version = re.findall(
+        version = re.findall(r"^__version__ = \"([^']+)\"\r?$", fp.read(), re.M)[0]
-            r"^__version__ = \"([^']+)\"\r?$", fp.read(), re.M
-        )[0]
     except IndexError:
         raise RuntimeError("Unable to determine version.")
 
@@ -71,9 +68,7 @@ setup_kwargs = {
     ],
 }
 
-env_dependency = (
+env_dependency = '; sys_platform != "win32" ' 'and implementation_name == "cpython"'
-    '; sys_platform != "win32" ' 'and implementation_name == "cpython"'
-)
 ujson = "ujson>=1.35" + env_dependency
 uvloop = "uvloop>=0.5.3" + env_dependency
 
@@ -83,13 +78,13 @@ requirements = [
     ujson,
     "aiofiles>=0.3.0",
     "websockets>=7.0,<9.0",
-    "multidict>=4.0,<5.0",
+    "multidict==5.0.0",
     "httpx==0.9.3",
 ]
 
 tests_require = [
     "pytest==5.2.1",
-    "multidict>=4.0,<5.0",
+    "multidict==5.0.0",
     "gunicorn",
     "pytest-cov",
     "httpcore==0.3.0",

tests/test_response.py

@@ -232,6 +232,12 @@ def test_chunked_streaming_returns_correct_content(streaming_app):
     assert response.text == "foo,bar"
 
 
+@pytest.mark.asyncio
+async def test_chunked_streaming_returns_correct_content_asgi(streaming_app):
+    request, response = await streaming_app.asgi_client.get("/")
+    assert response.text == "4\r\nfoo,\r\n3\r\nbar\r\n0\r\n\r\n"
+
+
 def test_non_chunked_streaming_adds_correct_headers(non_chunked_streaming_app):
     request, response = non_chunked_streaming_app.test_client.get("/")
     assert "Transfer-Encoding" not in response.headers
@@ -239,6 +245,16 @@ def test_non_chunked_streaming_adds_correct_headers(non_chunked_streaming_app):
     assert response.headers["Content-Length"] == "7"
 
 
+@pytest.mark.asyncio
+async def test_non_chunked_streaming_adds_correct_headers_asgi(
+    non_chunked_streaming_app,
+):
+    request, response = await non_chunked_streaming_app.asgi_client.get("/")
+    assert "Transfer-Encoding" not in response.headers
+    assert response.headers["Content-Type"] == "text/csv"
+    assert response.headers["Content-Length"] == "7"
+
+
 def test_non_chunked_streaming_returns_correct_content(
     non_chunked_streaming_app,
 ):