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Mini Shell
Mini Shell
import asyncio
import asyncio.streams
import traceback
import warnings
from collections import deque
from contextlib import suppress
from html import escape as html_escape
from http import HTTPStatus
from logging import Logger
from typing import (
TYPE_CHECKING,
Any,
Awaitable,
Callable,
Deque,
Optional,
Sequence,
Tuple,
Type,
Union,
cast,
)
import attr
import yarl
from .abc import AbstractAccessLogger, AbstractStreamWriter
from .base_protocol import BaseProtocol
from .helpers import ceil_timeout
from .http import (
HttpProcessingError,
HttpRequestParser,
HttpVersion10,
RawRequestMessage,
StreamWriter,
)
from .log import access_logger, server_logger
from .streams import EMPTY_PAYLOAD, StreamReader
from .tcp_helpers import tcp_keepalive
from .web_exceptions import HTTPException
from .web_log import AccessLogger
from .web_request import BaseRequest
from .web_response import Response, StreamResponse
__all__ = ("RequestHandler", "RequestPayloadError", "PayloadAccessError")
if TYPE_CHECKING:
from .web_server import Server
_RequestFactory = Callable[
[
RawRequestMessage,
StreamReader,
"RequestHandler",
AbstractStreamWriter,
"asyncio.Task[None]",
],
BaseRequest,
]
_RequestHandler = Callable[[BaseRequest], Awaitable[StreamResponse]]
ERROR = RawRequestMessage(
"UNKNOWN",
"/",
HttpVersion10,
{}, # type: ignore[arg-type]
{}, # type: ignore[arg-type]
True,
None,
False,
False,
yarl.URL("/"),
)
class RequestPayloadError(Exception):
"""Payload parsing error."""
class PayloadAccessError(Exception):
"""Payload was accessed after response was sent."""
@attr.s(auto_attribs=True, frozen=True, slots=True)
class _ErrInfo:
status: int
exc: BaseException
message: str
_MsgType = Tuple[Union[RawRequestMessage, _ErrInfo], StreamReader]
class RequestHandler(BaseProtocol):
"""HTTP protocol implementation.
RequestHandler handles incoming HTTP request. It reads request line,
request headers and request payload and calls handle_request() method.
By default it always returns with 404 response.
RequestHandler handles errors in incoming request, like bad
status line, bad headers or incomplete payload. If any error occurs,
connection gets closed.
keepalive_timeout -- number of seconds before closing
keep-alive connection
tcp_keepalive -- TCP keep-alive is on, default is on
debug -- enable debug mode
logger -- custom logger object
access_log_class -- custom class for access_logger
access_log -- custom logging object
access_log_format -- access log format string
loop -- Optional event loop
max_line_size -- Optional maximum header line size
max_field_size -- Optional maximum header field size
max_headers -- Optional maximum header size
timeout_ceil_threshold -- Optional value to specify
threshold to ceil() timeout
values
"""
KEEPALIVE_RESCHEDULE_DELAY = 1
__slots__ = (
"_request_count",
"_keepalive",
"_manager",
"_request_handler",
"_request_factory",
"_tcp_keepalive",
"_keepalive_time",
"_keepalive_handle",
"_keepalive_timeout",
"_lingering_time",
"_messages",
"_message_tail",
"_waiter",
"_task_handler",
"_upgrade",
"_payload_parser",
"_request_parser",
"_reading_paused",
"logger",
"debug",
"access_log",
"access_logger",
"_close",
"_force_close",
"_current_request",
"_timeout_ceil_threshold",
)
def __init__(
self,
manager: "Server",
*,
loop: asyncio.AbstractEventLoop,
keepalive_timeout: float = 75.0, # NGINX default is 75 secs
tcp_keepalive: bool = True,
logger: Logger = server_logger,
access_log_class: Type[AbstractAccessLogger] = AccessLogger,
access_log: Logger = access_logger,
access_log_format: str = AccessLogger.LOG_FORMAT,
debug: bool = False,
max_line_size: int = 8190,
max_headers: int = 32768,
max_field_size: int = 8190,
lingering_time: float = 10.0,
read_bufsize: int = 2**16,
auto_decompress: bool = True,
timeout_ceil_threshold: float = 5,
):
super().__init__(loop)
self._request_count = 0
self._keepalive = False
self._current_request: Optional[BaseRequest] = None
self._manager: Optional[Server] = manager
self._request_handler: Optional[_RequestHandler] = manager.request_handler
self._request_factory: Optional[_RequestFactory] = manager.request_factory
self._tcp_keepalive = tcp_keepalive
# placeholder to be replaced on keepalive timeout setup
self._keepalive_time = 0.0
self._keepalive_handle: Optional[asyncio.Handle] = None
self._keepalive_timeout = keepalive_timeout
self._lingering_time = float(lingering_time)
self._messages: Deque[_MsgType] = deque()
self._message_tail = b""
self._waiter: Optional[asyncio.Future[None]] = None
self._task_handler: Optional[asyncio.Task[None]] = None
self._upgrade = False
self._payload_parser: Any = None
self._request_parser: Optional[HttpRequestParser] = HttpRequestParser(
self,
loop,
read_bufsize,
max_line_size=max_line_size,
max_field_size=max_field_size,
max_headers=max_headers,
payload_exception=RequestPayloadError,
auto_decompress=auto_decompress,
)
self._timeout_ceil_threshold: float = 5
try:
self._timeout_ceil_threshold = float(timeout_ceil_threshold)
except (TypeError, ValueError):
pass
self.logger = logger
self.debug = debug
self.access_log = access_log
if access_log:
self.access_logger: Optional[AbstractAccessLogger] = access_log_class(
access_log, access_log_format
)
else:
self.access_logger = None
self._close = False
self._force_close = False
def __repr__(self) -> str:
return "<{} {}>".format(
self.__class__.__name__,
"connected" if self.transport is not None else "disconnected",
)
@property
def keepalive_timeout(self) -> float:
return self._keepalive_timeout
async def shutdown(self, timeout: Optional[float] = 15.0) -> None:
"""Do worker process exit preparations.
We need to clean up everything and stop accepting requests.
It is especially important for keep-alive connections.
"""
self._force_close = True
if self._keepalive_handle is not None:
self._keepalive_handle.cancel()
if self._waiter:
self._waiter.cancel()
# wait for handlers
with suppress(asyncio.CancelledError, asyncio.TimeoutError):
async with ceil_timeout(timeout):
if self._current_request is not None:
self._current_request._cancel(asyncio.CancelledError())
if self._task_handler is not None and not self._task_handler.done():
await self._task_handler
# force-close non-idle handler
if self._task_handler is not None:
self._task_handler.cancel()
if self.transport is not None:
self.transport.close()
self.transport = None
def connection_made(self, transport: asyncio.BaseTransport) -> None:
super().connection_made(transport)
real_transport = cast(asyncio.Transport, transport)
if self._tcp_keepalive:
tcp_keepalive(real_transport)
self._task_handler = self._loop.create_task(self.start())
assert self._manager is not None
self._manager.connection_made(self, real_transport)
def connection_lost(self, exc: Optional[BaseException]) -> None:
if self._manager is None:
return
self._manager.connection_lost(self, exc)
super().connection_lost(exc)
# Grab value before setting _manager to None.
handler_cancellation = self._manager.handler_cancellation
self._manager = None
self._force_close = True
self._request_factory = None
self._request_handler = None
self._request_parser = None
if self._keepalive_handle is not None:
self._keepalive_handle.cancel()
if self._current_request is not None:
if exc is None:
exc = ConnectionResetError("Connection lost")
self._current_request._cancel(exc)
if self._waiter is not None:
self._waiter.cancel()
if handler_cancellation and self._task_handler is not None:
self._task_handler.cancel()
self._task_handler = None
if self._payload_parser is not None:
self._payload_parser.feed_eof()
self._payload_parser = None
def set_parser(self, parser: Any) -> None:
# Actual type is WebReader
assert self._payload_parser is None
self._payload_parser = parser
if self._message_tail:
self._payload_parser.feed_data(self._message_tail)
self._message_tail = b""
def eof_received(self) -> None:
pass
def data_received(self, data: bytes) -> None:
if self._force_close or self._close:
return
# parse http messages
messages: Sequence[_MsgType]
if self._payload_parser is None and not self._upgrade:
assert self._request_parser is not None
try:
messages, upgraded, tail = self._request_parser.feed_data(data)
except HttpProcessingError as exc:
messages = [
(_ErrInfo(status=400, exc=exc, message=exc.message), EMPTY_PAYLOAD)
]
upgraded = False
tail = b""
for msg, payload in messages or ():
self._request_count += 1
self._messages.append((msg, payload))
waiter = self._waiter
if messages and waiter is not None and not waiter.done():
# don't set result twice
waiter.set_result(None)
self._upgrade = upgraded
if upgraded and tail:
self._message_tail = tail
# no parser, just store
elif self._payload_parser is None and self._upgrade and data:
self._message_tail += data
# feed payload
elif data:
eof, tail = self._payload_parser.feed_data(data)
if eof:
self.close()
def keep_alive(self, val: bool) -> None:
"""Set keep-alive connection mode.
:param bool val: new state.
"""
self._keepalive = val
if self._keepalive_handle:
self._keepalive_handle.cancel()
self._keepalive_handle = None
def close(self) -> None:
"""Close connection.
Stop accepting new pipelining messages and close
connection when handlers done processing messages.
"""
self._close = True
if self._waiter:
self._waiter.cancel()
def force_close(self) -> None:
"""Forcefully close connection."""
self._force_close = True
if self._waiter:
self._waiter.cancel()
if self.transport is not None:
self.transport.close()
self.transport = None
def log_access(
self, request: BaseRequest, response: StreamResponse, time: float
) -> None:
if self.access_logger is not None:
self.access_logger.log(request, response, self._loop.time() - time)
def log_debug(self, *args: Any, **kw: Any) -> None:
if self.debug:
self.logger.debug(*args, **kw)
def log_exception(self, *args: Any, **kw: Any) -> None:
self.logger.exception(*args, **kw)
def _process_keepalive(self) -> None:
if self._force_close or not self._keepalive:
return
next = self._keepalive_time + self._keepalive_timeout
# handler in idle state
if self._waiter:
if self._loop.time() > next:
self.force_close()
return
# not all request handlers are done,
# reschedule itself to next second
self._keepalive_handle = self._loop.call_later(
self.KEEPALIVE_RESCHEDULE_DELAY,
self._process_keepalive,
)
async def _handle_request(
self,
request: BaseRequest,
start_time: float,
request_handler: Callable[[BaseRequest], Awaitable[StreamResponse]],
) -> Tuple[StreamResponse, bool]:
assert self._request_handler is not None
try:
try:
self._current_request = request
resp = await request_handler(request)
finally:
self._current_request = None
except HTTPException as exc:
resp = exc
reset = await self.finish_response(request, resp, start_time)
except asyncio.CancelledError:
raise
except asyncio.TimeoutError as exc:
self.log_debug("Request handler timed out.", exc_info=exc)
resp = self.handle_error(request, 504)
reset = await self.finish_response(request, resp, start_time)
except Exception as exc:
resp = self.handle_error(request, 500, exc)
reset = await self.finish_response(request, resp, start_time)
else:
# Deprecation warning (See #2415)
if getattr(resp, "__http_exception__", False):
warnings.warn(
"returning HTTPException object is deprecated "
"(#2415) and will be removed, "
"please raise the exception instead",
DeprecationWarning,
)
reset = await self.finish_response(request, resp, start_time)
return resp, reset
async def start(self) -> None:
"""Process incoming request.
It reads request line, request headers and request payload, then
calls handle_request() method. Subclass has to override
handle_request(). start() handles various exceptions in request
or response handling. Connection is being closed always unless
keep_alive(True) specified.
"""
loop = self._loop
handler = self._task_handler
assert handler is not None
manager = self._manager
assert manager is not None
keepalive_timeout = self._keepalive_timeout
resp = None
assert self._request_factory is not None
assert self._request_handler is not None
while not self._force_close:
if not self._messages:
try:
# wait for next request
self._waiter = loop.create_future()
await self._waiter
except asyncio.CancelledError:
break
finally:
self._waiter = None
message, payload = self._messages.popleft()
start = loop.time()
manager.requests_count += 1
writer = StreamWriter(self, loop)
if isinstance(message, _ErrInfo):
# make request_factory work
request_handler = self._make_error_handler(message)
message = ERROR
else:
request_handler = self._request_handler
request = self._request_factory(message, payload, self, writer, handler)
try:
# a new task is used for copy context vars (#3406)
task = self._loop.create_task(
self._handle_request(request, start, request_handler)
)
try:
resp, reset = await task
except (asyncio.CancelledError, ConnectionError):
self.log_debug("Ignored premature client disconnection")
break
# Drop the processed task from asyncio.Task.all_tasks() early
del task
if reset:
self.log_debug("Ignored premature client disconnection 2")
break
# notify server about keep-alive
self._keepalive = bool(resp.keep_alive)
# check payload
if not payload.is_eof():
lingering_time = self._lingering_time
if not self._force_close and lingering_time:
self.log_debug(
"Start lingering close timer for %s sec.", lingering_time
)
now = loop.time()
end_t = now + lingering_time
with suppress(asyncio.TimeoutError, asyncio.CancelledError):
while not payload.is_eof() and now < end_t:
async with ceil_timeout(end_t - now):
# read and ignore
await payload.readany()
now = loop.time()
# if payload still uncompleted
if not payload.is_eof() and not self._force_close:
self.log_debug("Uncompleted request.")
self.close()
payload.set_exception(PayloadAccessError())
except asyncio.CancelledError:
self.log_debug("Ignored premature client disconnection ")
break
except RuntimeError as exc:
if self.debug:
self.log_exception("Unhandled runtime exception", exc_info=exc)
self.force_close()
except Exception as exc:
self.log_exception("Unhandled exception", exc_info=exc)
self.force_close()
finally:
if self.transport is None and resp is not None:
self.log_debug("Ignored premature client disconnection.")
elif not self._force_close:
if self._keepalive and not self._close:
# start keep-alive timer
if keepalive_timeout is not None:
now = self._loop.time()
self._keepalive_time = now
if self._keepalive_handle is None:
self._keepalive_handle = loop.call_at(
now + keepalive_timeout, self._process_keepalive
)
else:
break
# remove handler, close transport if no handlers left
if not self._force_close:
self._task_handler = None
if self.transport is not None:
self.transport.close()
async def finish_response(
self, request: BaseRequest, resp: StreamResponse, start_time: float
) -> bool:
"""Prepare the response and write_eof, then log access.
This has to
be called within the context of any exception so the access logger
can get exception information. Returns True if the client disconnects
prematurely.
"""
if self._request_parser is not None:
self._request_parser.set_upgraded(False)
self._upgrade = False
if self._message_tail:
self._request_parser.feed_data(self._message_tail)
self._message_tail = b""
try:
prepare_meth = resp.prepare
except AttributeError:
if resp is None:
raise RuntimeError("Missing return " "statement on request handler")
else:
raise RuntimeError(
"Web-handler should return "
"a response instance, "
"got {!r}".format(resp)
)
try:
await prepare_meth(request)
await resp.write_eof()
except ConnectionError:
self.log_access(request, resp, start_time)
return True
else:
self.log_access(request, resp, start_time)
return False
def handle_error(
self,
request: BaseRequest,
status: int = 500,
exc: Optional[BaseException] = None,
message: Optional[str] = None,
) -> StreamResponse:
"""Handle errors.
Returns HTTP response with specific status code. Logs additional
information. It always closes current connection.
"""
self.log_exception("Error handling request", exc_info=exc)
# some data already got sent, connection is broken
if request.writer.output_size > 0:
raise ConnectionError(
"Response is sent already, cannot send another response "
"with the error message"
)
ct = "text/plain"
if status == HTTPStatus.INTERNAL_SERVER_ERROR:
title = "{0.value} {0.phrase}".format(HTTPStatus.INTERNAL_SERVER_ERROR)
msg = HTTPStatus.INTERNAL_SERVER_ERROR.description
tb = None
if self.debug:
with suppress(Exception):
tb = traceback.format_exc()
if "text/html" in request.headers.get("Accept", ""):
if tb:
tb = html_escape(tb)
msg = f"<h2>Traceback:</h2>\n<pre>{tb}</pre>"
message = (
"<html><head>"
"<title>{title}</title>"
"</head><body>\n<h1>{title}</h1>"
"\n{msg}\n</body></html>\n"
).format(title=title, msg=msg)
ct = "text/html"
else:
if tb:
msg = tb
message = title + "\n\n" + msg
resp = Response(status=status, text=message, content_type=ct)
resp.force_close()
return resp
def _make_error_handler(
self, err_info: _ErrInfo
) -> Callable[[BaseRequest], Awaitable[StreamResponse]]:
async def handler(request: BaseRequest) -> StreamResponse:
return self.handle_error(
request, err_info.status, err_info.exc, err_info.message
)
return handler
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