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from typing import Any, Union
from ..exceptions import ConnectionError, InvalidResponse, ResponseError
from ..typing import EncodableT
from .base import _AsyncRESPBase, _RESPBase
from .socket import SERVER_CLOSED_CONNECTION_ERROR
class _RESP2Parser(_RESPBase):
"""RESP2 protocol implementation"""
def read_response(self, disable_decoding=False):
pos = self._buffer.get_pos() if self._buffer else None
try:
result = self._read_response(disable_decoding=disable_decoding)
except BaseException:
if self._buffer:
self._buffer.rewind(pos)
raise
else:
self._buffer.purge()
return result
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:]
# 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":":
return int(response)
# bulk response
elif byte == b"$" and response == b"-1":
return None
elif byte == b"$":
response = self._buffer.read(int(response))
# multi-bulk response
elif byte == b"*" and response == b"-1":
return None
elif byte == b"*":
response = [
self._read_response(disable_decoding=disable_decoding)
for i in range(int(response))
]
else:
raise InvalidResponse(f"Protocol Error: {raw!r}")
if disable_decoding is False:
response = self.encoder.decode(response)
return response
class _AsyncRESP2Parser(_AsyncRESPBase):
"""Async class for the RESP2 protocol"""
async def read_response(self, disable_decoding: bool = False):
if not self._connected:
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
if self._chunks:
# augment parsing buffer with previously read data
self._buffer += b"".join(self._chunks)
self._chunks.clear()
self._pos = 0
response = await self._read_response(disable_decoding=disable_decoding)
# Successfully parsing a response allows us to clear our parsing buffer
self._clear()
return response
async def _read_response(
self, disable_decoding: bool = False
) -> Union[EncodableT, ResponseError, None]:
raw = await self._readline()
response: Any
byte, response = raw[:1], raw[1:]
# 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):
self._clear() # Successful parse
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":":
return int(response)
# bulk response
elif byte == b"$" and response == b"-1":
return None
elif byte == b"$":
response = await self._read(int(response))
# multi-bulk response
elif byte == b"*" and response == b"-1":
return None
elif byte == b"*":
response = [
(await self._read_response(disable_decoding))
for _ in range(int(response)) # noqa
]
else:
raise InvalidResponse(f"Protocol Error: {raw!r}")
if disable_decoding is False:
response = self.encoder.decode(response)
return response
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