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