631 lines
20 KiB
Python
631 lines
20 KiB
Python
import asyncio
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import collections
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import warnings
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from typing import List # noqa
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from typing import Awaitable, Callable, Generic, Optional, Tuple, TypeVar
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from .base_protocol import BaseProtocol
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from .helpers import BaseTimerContext, set_exception, set_result
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from .log import internal_logger
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try: # pragma: no cover
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from typing import Deque # noqa
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except ImportError:
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from typing_extensions import Deque # noqa
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__all__ = (
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'EMPTY_PAYLOAD', 'EofStream', 'StreamReader', 'DataQueue',
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'FlowControlDataQueue')
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DEFAULT_LIMIT = 2 ** 16
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_T = TypeVar('_T')
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class EofStream(Exception):
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"""eof stream indication."""
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class AsyncStreamIterator(Generic[_T]):
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def __init__(self, read_func: Callable[[], Awaitable[_T]]) -> None:
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self.read_func = read_func
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def __aiter__(self) -> 'AsyncStreamIterator[_T]':
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return self
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async def __anext__(self) -> _T:
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try:
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rv = await self.read_func()
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except EofStream:
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raise StopAsyncIteration # NOQA
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if rv == b'':
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raise StopAsyncIteration # NOQA
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return rv
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class ChunkTupleAsyncStreamIterator:
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def __init__(self, stream: 'StreamReader') -> None:
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self._stream = stream
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def __aiter__(self) -> 'ChunkTupleAsyncStreamIterator':
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return self
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async def __anext__(self) -> Tuple[bytes, bool]:
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rv = await self._stream.readchunk()
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if rv == (b'', False):
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raise StopAsyncIteration # NOQA
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return rv
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class AsyncStreamReaderMixin:
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def __aiter__(self) -> AsyncStreamIterator[bytes]:
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return AsyncStreamIterator(self.readline) # type: ignore
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def iter_chunked(self, n: int) -> AsyncStreamIterator[bytes]:
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"""Returns an asynchronous iterator that yields chunks of size n.
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Python-3.5 available for Python 3.5+ only
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"""
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return AsyncStreamIterator(lambda: self.read(n)) # type: ignore
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def iter_any(self) -> AsyncStreamIterator[bytes]:
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"""Returns an asynchronous iterator that yields all the available
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data as soon as it is received
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Python-3.5 available for Python 3.5+ only
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"""
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return AsyncStreamIterator(self.readany) # type: ignore
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def iter_chunks(self) -> ChunkTupleAsyncStreamIterator:
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"""Returns an asynchronous iterator that yields chunks of data
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as they are received by the server. The yielded objects are tuples
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of (bytes, bool) as returned by the StreamReader.readchunk method.
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Python-3.5 available for Python 3.5+ only
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"""
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return ChunkTupleAsyncStreamIterator(self) # type: ignore
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class StreamReader(AsyncStreamReaderMixin):
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"""An enhancement of asyncio.StreamReader.
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Supports asynchronous iteration by line, chunk or as available::
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async for line in reader:
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...
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async for chunk in reader.iter_chunked(1024):
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...
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async for slice in reader.iter_any():
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...
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"""
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total_bytes = 0
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def __init__(self, protocol: BaseProtocol,
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*, limit: int=DEFAULT_LIMIT,
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timer: Optional[BaseTimerContext]=None,
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loop: Optional[asyncio.AbstractEventLoop]=None) -> None:
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self._protocol = protocol
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self._low_water = limit
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self._high_water = limit * 2
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if loop is None:
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loop = asyncio.get_event_loop()
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self._loop = loop
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self._size = 0
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self._cursor = 0
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self._http_chunk_splits = None # type: Optional[List[int]]
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self._buffer = collections.deque() # type: Deque[bytes]
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self._buffer_offset = 0
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self._eof = False
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self._waiter = None # type: Optional[asyncio.Future[bool]]
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self._eof_waiter = None # type: Optional[asyncio.Future[bool]]
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self._exception = None # type: Optional[BaseException]
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self._timer = timer
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self._eof_callbacks = [] # type: List[Callable[[], None]]
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def __repr__(self) -> str:
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info = [self.__class__.__name__]
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if self._size:
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info.append('%d bytes' % self._size)
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if self._eof:
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info.append('eof')
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if self._low_water != DEFAULT_LIMIT:
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info.append('low=%d high=%d' % (self._low_water, self._high_water))
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if self._waiter:
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info.append('w=%r' % self._waiter)
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if self._exception:
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info.append('e=%r' % self._exception)
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return '<%s>' % ' '.join(info)
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def exception(self) -> Optional[BaseException]:
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return self._exception
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def set_exception(self, exc: BaseException) -> None:
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self._exception = exc
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self._eof_callbacks.clear()
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waiter = self._waiter
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if waiter is not None:
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self._waiter = None
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set_exception(waiter, exc)
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waiter = self._eof_waiter
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if waiter is not None:
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set_exception(waiter, exc)
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self._eof_waiter = None
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def on_eof(self, callback: Callable[[], None]) -> None:
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if self._eof:
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try:
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callback()
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except Exception:
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internal_logger.exception('Exception in eof callback')
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else:
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self._eof_callbacks.append(callback)
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def feed_eof(self) -> None:
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self._eof = True
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waiter = self._waiter
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if waiter is not None:
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self._waiter = None
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set_result(waiter, True)
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waiter = self._eof_waiter
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if waiter is not None:
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self._eof_waiter = None
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set_result(waiter, True)
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for cb in self._eof_callbacks:
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try:
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cb()
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except Exception:
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internal_logger.exception('Exception in eof callback')
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self._eof_callbacks.clear()
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def is_eof(self) -> bool:
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"""Return True if 'feed_eof' was called."""
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return self._eof
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def at_eof(self) -> bool:
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"""Return True if the buffer is empty and 'feed_eof' was called."""
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return self._eof and not self._buffer
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async def wait_eof(self) -> None:
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if self._eof:
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return
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assert self._eof_waiter is None
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self._eof_waiter = self._loop.create_future()
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try:
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await self._eof_waiter
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finally:
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self._eof_waiter = None
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def unread_data(self, data: bytes) -> None:
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""" rollback reading some data from stream, inserting it to buffer head.
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"""
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warnings.warn("unread_data() is deprecated "
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"and will be removed in future releases (#3260)",
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DeprecationWarning,
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stacklevel=2)
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if not data:
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return
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if self._buffer_offset:
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self._buffer[0] = self._buffer[0][self._buffer_offset:]
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self._buffer_offset = 0
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self._size += len(data)
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self._cursor -= len(data)
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self._buffer.appendleft(data)
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self._eof_counter = 0
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# TODO: size is ignored, remove the param later
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def feed_data(self, data: bytes, size: int=0) -> None:
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assert not self._eof, 'feed_data after feed_eof'
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if not data:
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return
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self._size += len(data)
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self._buffer.append(data)
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self.total_bytes += len(data)
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waiter = self._waiter
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if waiter is not None:
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self._waiter = None
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set_result(waiter, False)
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if (self._size > self._high_water and
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not self._protocol._reading_paused):
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self._protocol.pause_reading()
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def begin_http_chunk_receiving(self) -> None:
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if self._http_chunk_splits is None:
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if self.total_bytes:
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raise RuntimeError("Called begin_http_chunk_receiving when"
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"some data was already fed")
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self._http_chunk_splits = []
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def end_http_chunk_receiving(self) -> None:
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if self._http_chunk_splits is None:
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raise RuntimeError("Called end_chunk_receiving without calling "
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"begin_chunk_receiving first")
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# self._http_chunk_splits contains logical byte offsets from start of
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# the body transfer. Each offset is the offset of the end of a chunk.
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# "Logical" means bytes, accessible for a user.
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# If no chunks containig logical data were received, current position
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# is difinitely zero.
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pos = self._http_chunk_splits[-1] if self._http_chunk_splits else 0
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if self.total_bytes == pos:
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# We should not add empty chunks here. So we check for that.
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# Note, when chunked + gzip is used, we can receive a chunk
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# of compressed data, but that data may not be enough for gzip FSM
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# to yield any uncompressed data. That's why current position may
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# not change after receiving a chunk.
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return
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self._http_chunk_splits.append(self.total_bytes)
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# wake up readchunk when end of http chunk received
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waiter = self._waiter
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if waiter is not None:
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self._waiter = None
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set_result(waiter, False)
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async def _wait(self, func_name: str) -> None:
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# StreamReader uses a future to link the protocol feed_data() method
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# to a read coroutine. Running two read coroutines at the same time
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# would have an unexpected behaviour. It would not possible to know
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# which coroutine would get the next data.
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if self._waiter is not None:
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raise RuntimeError('%s() called while another coroutine is '
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'already waiting for incoming data' % func_name)
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waiter = self._waiter = self._loop.create_future()
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try:
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if self._timer:
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with self._timer:
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await waiter
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else:
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await waiter
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finally:
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self._waiter = None
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async def readline(self) -> bytes:
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if self._exception is not None:
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raise self._exception
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line = []
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line_size = 0
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not_enough = True
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while not_enough:
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while self._buffer and not_enough:
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offset = self._buffer_offset
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ichar = self._buffer[0].find(b'\n', offset) + 1
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# Read from current offset to found b'\n' or to the end.
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data = self._read_nowait_chunk(ichar - offset if ichar else -1)
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line.append(data)
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line_size += len(data)
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if ichar:
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not_enough = False
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if line_size > self._high_water:
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raise ValueError('Line is too long')
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if self._eof:
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break
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if not_enough:
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await self._wait('readline')
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return b''.join(line)
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|
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async def read(self, n: int=-1) -> bytes:
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if self._exception is not None:
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raise self._exception
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|
# migration problem; with DataQueue you have to catch
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# EofStream exception, so common way is to run payload.read() inside
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# infinite loop. what can cause real infinite loop with StreamReader
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# lets keep this code one major release.
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if __debug__:
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if self._eof and not self._buffer:
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self._eof_counter = getattr(self, '_eof_counter', 0) + 1
|
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if self._eof_counter > 5:
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internal_logger.warning(
|
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'Multiple access to StreamReader in eof state, '
|
|
'might be infinite loop.', stack_info=True)
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if not n:
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return b''
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|
|
if n < 0:
|
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# This used to just loop creating a new waiter hoping to
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# collect everything in self._buffer, but that would
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# deadlock if the subprocess sends more than self.limit
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# bytes. So just call self.readany() until EOF.
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blocks = []
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while True:
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block = await self.readany()
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if not block:
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break
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blocks.append(block)
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return b''.join(blocks)
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|
|
# TODO: should be `if` instead of `while`
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# because waiter maybe triggered on chunk end,
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# without feeding any data
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while not self._buffer and not self._eof:
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await self._wait('read')
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|
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return self._read_nowait(n)
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|
|
async def readany(self) -> bytes:
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if self._exception is not None:
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raise self._exception
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|
|
|
# TODO: should be `if` instead of `while`
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# because waiter maybe triggered on chunk end,
|
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# without feeding any data
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|
while not self._buffer and not self._eof:
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await self._wait('readany')
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|
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return self._read_nowait(-1)
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|
|
async def readchunk(self) -> Tuple[bytes, bool]:
|
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"""Returns a tuple of (data, end_of_http_chunk). When chunked transfer
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encoding is used, end_of_http_chunk is a boolean indicating if the end
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of the data corresponds to the end of a HTTP chunk , otherwise it is
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always False.
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"""
|
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if self._exception is not None:
|
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raise self._exception
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|
|
|
if not self._buffer and not self._eof:
|
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if (self._http_chunk_splits and
|
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self._cursor == self._http_chunk_splits[0]):
|
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# end of http chunk without available data
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self._http_chunk_splits = self._http_chunk_splits[1:]
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return (b"", True)
|
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await self._wait('readchunk')
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|
|
|
if not self._buffer and not self._http_chunk_splits:
|
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# end of file
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return (b"", False)
|
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elif self._http_chunk_splits is not None:
|
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while self._http_chunk_splits:
|
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pos = self._http_chunk_splits[0]
|
|
self._http_chunk_splits = self._http_chunk_splits[1:]
|
|
if pos == self._cursor:
|
|
return (b"", True)
|
|
if pos > self._cursor:
|
|
return (self._read_nowait(pos-self._cursor), True)
|
|
return (self._read_nowait(-1), False)
|
|
else:
|
|
return (self._read_nowait_chunk(-1), False)
|
|
|
|
async def readexactly(self, n: int) -> bytes:
|
|
if self._exception is not None:
|
|
raise self._exception
|
|
|
|
blocks = [] # type: List[bytes]
|
|
while n > 0:
|
|
block = await self.read(n)
|
|
if not block:
|
|
partial = b''.join(blocks)
|
|
raise asyncio.streams.IncompleteReadError(
|
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partial, len(partial) + n)
|
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blocks.append(block)
|
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n -= len(block)
|
|
|
|
return b''.join(blocks)
|
|
|
|
def read_nowait(self, n: int=-1) -> bytes:
|
|
# default was changed to be consistent with .read(-1)
|
|
#
|
|
# I believe the most users don't know about the method and
|
|
# they are not affected.
|
|
if self._exception is not None:
|
|
raise self._exception
|
|
|
|
if self._waiter and not self._waiter.done():
|
|
raise RuntimeError(
|
|
'Called while some coroutine is waiting for incoming data.')
|
|
|
|
return self._read_nowait(n)
|
|
|
|
def _read_nowait_chunk(self, n: int) -> bytes:
|
|
first_buffer = self._buffer[0]
|
|
offset = self._buffer_offset
|
|
if n != -1 and len(first_buffer) - offset > n:
|
|
data = first_buffer[offset:offset + n]
|
|
self._buffer_offset += n
|
|
|
|
elif offset:
|
|
self._buffer.popleft()
|
|
data = first_buffer[offset:]
|
|
self._buffer_offset = 0
|
|
|
|
else:
|
|
data = self._buffer.popleft()
|
|
|
|
self._size -= len(data)
|
|
self._cursor += len(data)
|
|
|
|
if self._size < self._low_water and self._protocol._reading_paused:
|
|
self._protocol.resume_reading()
|
|
return data
|
|
|
|
def _read_nowait(self, n: int) -> bytes:
|
|
chunks = []
|
|
|
|
while self._buffer:
|
|
chunk = self._read_nowait_chunk(n)
|
|
chunks.append(chunk)
|
|
if n != -1:
|
|
n -= len(chunk)
|
|
if n == 0:
|
|
break
|
|
|
|
return b''.join(chunks) if chunks else b''
|
|
|
|
|
|
class EmptyStreamReader(AsyncStreamReaderMixin):
|
|
|
|
def exception(self) -> Optional[BaseException]:
|
|
return None
|
|
|
|
def set_exception(self, exc: BaseException) -> None:
|
|
pass
|
|
|
|
def on_eof(self, callback: Callable[[], None]) -> None:
|
|
try:
|
|
callback()
|
|
except Exception:
|
|
internal_logger.exception('Exception in eof callback')
|
|
|
|
def feed_eof(self) -> None:
|
|
pass
|
|
|
|
def is_eof(self) -> bool:
|
|
return True
|
|
|
|
def at_eof(self) -> bool:
|
|
return True
|
|
|
|
async def wait_eof(self) -> None:
|
|
return
|
|
|
|
def feed_data(self, data: bytes, n: int=0) -> None:
|
|
pass
|
|
|
|
async def readline(self) -> bytes:
|
|
return b''
|
|
|
|
async def read(self, n: int=-1) -> bytes:
|
|
return b''
|
|
|
|
async def readany(self) -> bytes:
|
|
return b''
|
|
|
|
async def readchunk(self) -> Tuple[bytes, bool]:
|
|
return (b'', True)
|
|
|
|
async def readexactly(self, n: int) -> bytes:
|
|
raise asyncio.streams.IncompleteReadError(b'', n)
|
|
|
|
def read_nowait(self) -> bytes:
|
|
return b''
|
|
|
|
|
|
EMPTY_PAYLOAD = EmptyStreamReader()
|
|
|
|
|
|
class DataQueue(Generic[_T]):
|
|
"""DataQueue is a general-purpose blocking queue with one reader."""
|
|
|
|
def __init__(self, loop: asyncio.AbstractEventLoop) -> None:
|
|
self._loop = loop
|
|
self._eof = False
|
|
self._waiter = None # type: Optional[asyncio.Future[bool]]
|
|
self._exception = None # type: Optional[BaseException]
|
|
self._size = 0
|
|
self._buffer = collections.deque() # type: Deque[Tuple[_T, int]]
|
|
|
|
def __len__(self) -> int:
|
|
return len(self._buffer)
|
|
|
|
def is_eof(self) -> bool:
|
|
return self._eof
|
|
|
|
def at_eof(self) -> bool:
|
|
return self._eof and not self._buffer
|
|
|
|
def exception(self) -> Optional[BaseException]:
|
|
return self._exception
|
|
|
|
def set_exception(self, exc: BaseException) -> None:
|
|
self._eof = True
|
|
self._exception = exc
|
|
|
|
waiter = self._waiter
|
|
if waiter is not None:
|
|
set_exception(waiter, exc)
|
|
self._waiter = None
|
|
|
|
def feed_data(self, data: _T, size: int=0) -> None:
|
|
self._size += size
|
|
self._buffer.append((data, size))
|
|
|
|
waiter = self._waiter
|
|
if waiter is not None:
|
|
self._waiter = None
|
|
set_result(waiter, True)
|
|
|
|
def feed_eof(self) -> None:
|
|
self._eof = True
|
|
|
|
waiter = self._waiter
|
|
if waiter is not None:
|
|
self._waiter = None
|
|
set_result(waiter, False)
|
|
|
|
async def read(self) -> _T:
|
|
if not self._buffer and not self._eof:
|
|
assert not self._waiter
|
|
self._waiter = self._loop.create_future()
|
|
try:
|
|
await self._waiter
|
|
except (asyncio.CancelledError, asyncio.TimeoutError):
|
|
self._waiter = None
|
|
raise
|
|
|
|
if self._buffer:
|
|
data, size = self._buffer.popleft()
|
|
self._size -= size
|
|
return data
|
|
else:
|
|
if self._exception is not None:
|
|
raise self._exception
|
|
else:
|
|
raise EofStream
|
|
|
|
def __aiter__(self) -> AsyncStreamIterator[_T]:
|
|
return AsyncStreamIterator(self.read)
|
|
|
|
|
|
class FlowControlDataQueue(DataQueue[_T]):
|
|
"""FlowControlDataQueue resumes and pauses an underlying stream.
|
|
|
|
It is a destination for parsed data."""
|
|
|
|
def __init__(self, protocol: BaseProtocol, *,
|
|
limit: int=DEFAULT_LIMIT,
|
|
loop: asyncio.AbstractEventLoop) -> None:
|
|
super().__init__(loop=loop)
|
|
|
|
self._protocol = protocol
|
|
self._limit = limit * 2
|
|
|
|
def feed_data(self, data: _T, size: int=0) -> None:
|
|
super().feed_data(data, size)
|
|
|
|
if self._size > self._limit and not self._protocol._reading_paused:
|
|
self._protocol.pause_reading()
|
|
|
|
async def read(self) -> _T:
|
|
try:
|
|
return await super().read()
|
|
finally:
|
|
if self._size < self._limit and self._protocol._reading_paused:
|
|
self._protocol.resume_reading()
|