forked from encode/uvicorn
/
wsgi.py
186 lines (169 loc) · 6.44 KB
/
wsgi.py
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import asyncio
import concurrent.futures
import io
import sys
from collections import deque
from typing import Deque, Iterable, Optional, Tuple
from asgiref.typing import (
ASGIReceiveCallable,
ASGIReceiveEvent,
ASGISendCallable,
ASGISendEvent,
HTTPRequestEvent,
HTTPResponseBodyEvent,
HTTPResponseStartEvent,
HTTPScope,
)
from uvicorn._types import Environ, ExcInfo, StartResponse, WSGIApp
def build_environ(
scope: HTTPScope, message: ASGIReceiveEvent, body: io.BytesIO
) -> Environ:
"""
Builds a scope and request message into a WSGI environ object.
"""
environ = {
"REQUEST_METHOD": scope["method"],
"SCRIPT_NAME": "",
"PATH_INFO": scope["path"].encode("utf8").decode("latin1"),
"QUERY_STRING": scope["query_string"].decode("ascii"),
"SERVER_PROTOCOL": "HTTP/%s" % scope["http_version"],
"wsgi.version": (1, 0),
"wsgi.url_scheme": scope.get("scheme", "http"),
"wsgi.input": body,
"wsgi.errors": sys.stdout,
"wsgi.multithread": True,
"wsgi.multiprocess": True,
"wsgi.run_once": False,
}
# Get server name and port - required in WSGI, not in ASGI
server = scope.get("server")
if server is None:
server = ("localhost", 80)
environ["SERVER_NAME"] = server[0]
environ["SERVER_PORT"] = server[1]
# Get client IP address
client = scope.get("client")
if client is not None:
environ["REMOTE_ADDR"] = client[0]
# Go through headers and make them into environ entries
for name, value in scope.get("headers", []):
name_str: str = name.decode("latin1")
if name_str == "content-length":
corrected_name = "CONTENT_LENGTH"
elif name_str == "content-type":
corrected_name = "CONTENT_TYPE"
else:
corrected_name = "HTTP_%s" % name_str.upper().replace("-", "_")
# HTTPbis say only ASCII chars are allowed in headers, but we latin1
# just in case
value_str: str = value.decode("latin1")
if corrected_name in environ:
corrected_name_environ = environ[corrected_name]
assert isinstance(corrected_name_environ, str)
value_str = corrected_name_environ + "," + value_str
environ[corrected_name] = value_str
return environ
class WSGIMiddleware:
def __init__(self, app: WSGIApp, workers: int = 10):
self.app = app
self.executor = concurrent.futures.ThreadPoolExecutor(max_workers=workers)
async def __call__(
self, scope: HTTPScope, receive: ASGIReceiveCallable, send: ASGISendCallable
) -> None:
assert scope["type"] == "http"
instance = WSGIResponder(self.app, self.executor, scope)
await instance(receive, send)
class WSGIResponder:
def __init__(
self,
app: WSGIApp,
executor: concurrent.futures.ThreadPoolExecutor,
scope: HTTPScope,
):
self.app = app
self.executor = executor
self.scope = scope
self.status = None
self.response_headers = None
self.send_event = asyncio.Event()
self.send_queue: Deque[Optional[ASGISendEvent]] = deque()
self.loop: asyncio.AbstractEventLoop = asyncio.get_event_loop()
self.response_started = False
self.exc_info: Optional[ExcInfo] = None
async def __call__(
self, receive: ASGIReceiveCallable, send: ASGISendCallable
) -> None:
message: HTTPRequestEvent = await receive() # type: ignore[assignment]
body = io.BytesIO(message.get("body", b""))
more_body = message.get("more_body", False)
if more_body:
body.seek(0, io.SEEK_END)
while more_body:
body_message: HTTPRequestEvent = (
await receive() # type: ignore[assignment]
)
body.write(body_message.get("body", b""))
more_body = body_message.get("more_body", False)
body.seek(0)
environ = build_environ(self.scope, message, body)
self.loop = asyncio.get_event_loop()
wsgi = self.loop.run_in_executor(
self.executor, self.wsgi, environ, self.start_response
)
sender = self.loop.create_task(self.sender(send))
try:
await asyncio.wait_for(wsgi, None)
finally:
self.send_queue.append(None)
self.send_event.set()
await asyncio.wait_for(sender, None)
if self.exc_info is not None:
raise self.exc_info[0].with_traceback(self.exc_info[1], self.exc_info[2])
async def sender(self, send: ASGISendCallable) -> None:
while True:
if self.send_queue:
message = self.send_queue.popleft()
if message is None:
return
await send(message)
else:
await self.send_event.wait()
self.send_event.clear()
def start_response(
self,
status: str,
response_headers: Iterable[Tuple[str, str]],
exc_info: Optional[ExcInfo] = None,
) -> None:
self.exc_info = exc_info
if not self.response_started:
self.response_started = True
status_code_str, _ = status.split(" ", 1)
status_code = int(status_code_str)
headers = [
(name.encode("ascii"), value.encode("ascii"))
for name, value in response_headers
]
http_response_start_event: HTTPResponseStartEvent = {
"type": "http.response.start",
"status": status_code,
"headers": headers,
}
self.send_queue.append(http_response_start_event)
self.loop.call_soon_threadsafe(self.send_event.set)
def wsgi(self, environ: Environ, start_response: StartResponse) -> None:
for chunk in self.app(environ, start_response): # type: ignore
response_body: HTTPResponseBodyEvent = {
"type": "http.response.body",
"body": chunk,
"more_body": True,
}
self.send_queue.append(response_body)
self.loop.call_soon_threadsafe(self.send_event.set)
empty_body: HTTPResponseBodyEvent = {
"type": "http.response.body",
"body": b"",
"more_body": False,
}
self.send_queue.append(empty_body)
self.loop.call_soon_threadsafe(self.send_event.set)