sync with starlette StreamingResponse

- adjust typing to latest starlette standard
- fix formatting
- fix mypy errors

examples/load_test.py

@@ -7,8 +7,9 @@
 # curl http://localhost:8000/stream | pv --line-mode --average-rate > /dev/null
 ################################################################################
 
-import uvicorn
 import json
+
+import uvicorn
 from fastapi import FastAPI, Request
 from sse_starlette.sse import EventSourceResponse
 

sse_starlette/sse.py

@@ -3,12 +3,22 @@
 import re
 from datetime import datetime
 from functools import partial
-from typing import Any, AsyncIterable, Callable, Coroutine, Dict, Optional, Union
+from typing import (
+    Any,
+    AsyncIterable,
+    Awaitable,
+    Callable,
+    Coroutine,
+    Iterator,
+    Mapping,
+    Optional,
+    Union,
+)
 
 import anyio
 from starlette.background import BackgroundTask
 from starlette.concurrency import iterate_in_threadpool
-from starlette.responses import Response
+from starlette.responses import AsyncContentStream, ContentStream, Response
 from starlette.types import Receive, Scope, Send
 
 _log = logging.getLogger(__name__)
@@ -137,14 +147,16 @@ class EventSourceResponse(Response):
     implementation based on Starlette StreamingResponse
     """
 
+    body_iterator: AsyncContentStream
+
     DEFAULT_PING_INTERVAL = 15
 
     # noinspection PyMissingConstructor
     def __init__(
         self,
-        content: Any,
+        content: ContentStream,
         status_code: int = 200,
-        headers: Optional[Dict] = None,
+        headers: Optional[Mapping[str, str]] = None,
         media_type: str = "text/event-stream",
         background: Optional[BackgroundTask] = None,
         ping: Optional[int] = None,
@@ -156,20 +168,21 @@ def __init__(
     ) -> None:
         if sep is not None and sep not in ["\r\n", "\r", "\n"]:
             raise ValueError(f"sep must be one of: \\r\\n, \\r, \\n, got: {sep}")
-        self.sep = sep
+        self.DEFAULT_SEPARATOR = "\r\n"
+        self.sep = sep if sep is not None else self.DEFAULT_SEPARATOR
+
         self.ping_message_factory = ping_message_factory
+
         if isinstance(content, AsyncIterable):
-            self.body_iterator = (
-                content
-            )  # type: AsyncIterable[Union[Any,dict,ServerSentEvent]]
+            self.body_iterator = content
         else:
-            self.body_iterator = iterate_in_threadpool(content)  # type: ignore
+            self.body_iterator = iterate_in_threadpool(content)
         self.status_code = status_code
         self.media_type = self.media_type if media_type is None else media_type
-        self.background = background  # type: ignore  # follows https://github.com/encode/starlette/blob/master/starlette/responses.py
+        self.background = background
         self.data_sender_callable = data_sender_callable
 
-        _headers = {}
+        _headers: dict[str, str] = {}
         if headers is not None:  # pragma: no cover
             _headers.update(headers)
 
@@ -215,7 +228,7 @@ async def listen_for_exit_signal() -> None:
         # Await the event
         await AppStatus.should_exit_event.wait()
 
-    async def stream_response(self, send) -> None:
+    async def stream_response(self, send: Send) -> None:
         await send(
             {
                 "type": "http.response.start",
@@ -235,7 +248,7 @@ async def stream_response(self, send) -> None:
     async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
         async with anyio.create_task_group() as task_group:
             # https://trio.readthedocs.io/en/latest/reference-core.html#custom-supervisors
-            async def wrap(func: Callable[[], Coroutine[None, None, None]]) -> None:
+            async def wrap(func: Callable[[], Awaitable[None]]) -> None:
                 await func()
                 # noinspection PyAsyncCall
                 task_group.cancel_scope.cancel()