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from asyncio import IncompleteReadError, TimeoutError
from typing import Any, Optional, Union
import async_timeout
from redis.typing import EncodableT
from ..exceptions import ConnectionError, InvalidResponse, RedisError, ResponseError
from .encoders import Encoder
from .protocol import AsyncBaseParser, BaseParser
from .socket import SERVER_CLOSED_CONNECTION_ERROR, SocketBuffer
class RESP2Parser(BaseParser):
"Plain Python parsing class"
def __init__(self, socket_read_size):
self.socket_read_size = socket_read_size
self.encoder = None
self._sock = None
self._buffer = None
def __del__(self):
try:
self.on_disconnect()
except Exception:
pass
def on_connect(self, connection):
"Called when the socket connects"
self._sock = connection._sock
self._buffer = SocketBuffer(
self._sock, self.socket_read_size, connection.socket_timeout
)
self.encoder = connection.encoder
def on_disconnect(self):
"Called when the socket disconnects"
self._sock = None
if self._buffer is not None:
self._buffer.close()
self._buffer = None
self.encoder = None
def can_read(self, timeout):
return self._buffer and self._buffer.can_read(timeout)
def read_response(self, disable_decoding=False):
raw = self._buffer.readline()
if not raw:
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
byte, response = raw[:1], raw[1:]
if byte not in (b"-", b"+", b":", b"$", b"*"):
raise InvalidResponse(f"Protocol Error: {raw!r}")
# server returned an error
if byte == b"-":
response = response.decode("utf-8", errors="replace")
error = self.parse_error(response)
# if the error is a ConnectionError, raise immediately so the user
# is notified
if isinstance(error, ConnectionError):
raise error
# otherwise, we're dealing with a ResponseError that might belong
# inside a pipeline response. the connection's read_response()
# and/or the pipeline's execute() will raise this error if
# necessary, so just return the exception instance here.
return error
# single value
elif byte == b"+":
pass
# int value
elif byte == b":":
response = int(response)
# bulk response
elif byte == b"$":
length = int(response)
if length == -1:
return None
response = self._buffer.read(length)
# multi-bulk response
elif byte == b"*":
length = int(response)
if length == -1:
return None
response = [
self.read_response(disable_decoding=disable_decoding)
for i in range(length)
]
if isinstance(response, bytes) and disable_decoding is False:
response = self.encoder.decode(response)
return response
class AsyncRESP2Parser(AsyncBaseParser):
"""Parsing class for the RESP2 protocol"""
__slots__ = AsyncBaseParser.__slots__ + ("encoder",)
def __init__(self, socket_read_size: int):
super().__init__(socket_read_size)
self.encoder: Optional[Encoder] = None
def on_connect(self, connection):
"""Called when the stream connects"""
self._stream = connection._reader
if self._stream is None:
raise RedisError("Buffer is closed.")
self.encoder = connection.encoder
def on_disconnect(self):
"""Called when the stream disconnects"""
if self._stream is not None:
self._stream = None
self.encoder = None
async def can_read_destructive(self) -> bool:
if self._stream is None:
raise RedisError("Buffer is closed.")
try:
async with async_timeout.timeout(0):
return await self._stream.read(1)
except TimeoutError:
return False
async def read_response(
self, disable_decoding: bool = False
) -> Union[EncodableT, ResponseError, None]:
if not self._stream or not self.encoder:
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
raw = await self._readline()
if not raw:
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
response: Any
byte, response = raw[:1], raw[1:]
if byte not in (b"-", b"+", b":", b"$", b"*"):
raise InvalidResponse(f"Protocol Error: {raw!r}")
# server returned an error
if byte == b"-":
response = response.decode("utf-8", errors="replace")
error = self.parse_error(response)
# if the error is a ConnectionError, raise immediately so the user
# is notified
if isinstance(error, ConnectionError):
raise error
# otherwise, we're dealing with a ResponseError that might belong
# inside a pipeline response. the connection's read_response()
# and/or the pipeline's execute() will raise this error if
# necessary, so just return the exception instance here.
return error
# single value
elif byte == b"+":
pass
# int value
elif byte == b":":
response = int(response)
# bulk response
elif byte == b"$":
length = int(response)
if length == -1:
return None
response = await self._read(length)
# multi-bulk response
elif byte == b"*":
length = int(response)
if length == -1:
return None
response = [
(await self.read_response(disable_decoding)) for _ in range(length)
]
if isinstance(response, bytes) and disable_decoding is False:
response = self.encoder.decode(response)
return response
async def _read(self, length: int) -> bytes:
"""
Read `length` bytes of data. These are assumed to be followed
by a '\r\n' terminator which is subsequently discarded.
"""
if self._stream is None:
raise RedisError("Buffer is closed.")
try:
data = await self._stream.readexactly(length + 2)
except IncompleteReadError as error:
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR) from error
return data[:-2]
async def _readline(self) -> bytes:
"""
read an unknown number of bytes up to the next '\r\n'
line separator, which is discarded.
"""
if self._stream is None:
raise RedisError("Buffer is closed.")
data = await self._stream.readline()
if not data.endswith(b"\r\n"):
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
return data[:-2]
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