Source code for langchain.output_parsers.fix
from __future__ import annotations
from typing import Any, TypeVar
from langchain_core.exceptions import OutputParserException
from langchain_core.language_models import BaseLanguageModel
from langchain_core.output_parsers import BaseOutputParser
from langchain_core.prompts import BasePromptTemplate
from langchain.output_parsers.prompts import NAIVE_FIX_PROMPT
T = TypeVar("T")
[docs]class OutputFixingParser(BaseOutputParser[T]):
"""封装一个解析器并尝试修复解析错误。"""
[docs] @classmethod
def is_lc_serializable(cls) -> bool:
return True
parser: BaseOutputParser[T]
"""用于解析输出的解析器。"""
# Should be an LLMChain but we want to avoid top-level imports from langchain.chains
retry_chain: Any
"""用于重试完成的LLMChain。"""
max_retries: int = 1
"""最大重试解析次数。"""
[docs] @classmethod
def from_llm(
cls,
llm: BaseLanguageModel,
parser: BaseOutputParser[T],
prompt: BasePromptTemplate = NAIVE_FIX_PROMPT,
max_retries: int = 1,
) -> OutputFixingParser[T]:
"""从语言模型和解析器创建一个OutputFixingParser。
参数:
llm:用于修复的llm
parser:用于解析的解析器
prompt:用于修复的提示
max_retries:最大重试解析次数。
返回:
OutputFixingParser
"""
from langchain.chains.llm import LLMChain
chain = LLMChain(llm=llm, prompt=prompt)
return cls(parser=parser, retry_chain=chain, max_retries=max_retries)
[docs] def parse(self, completion: str) -> T:
retries = 0
while retries <= self.max_retries:
try:
return self.parser.parse(completion)
except OutputParserException as e:
if retries == self.max_retries:
raise e
else:
retries += 1
completion = self.retry_chain.run(
instructions=self.parser.get_format_instructions(),
completion=completion,
error=repr(e),
)
raise OutputParserException("Failed to parse")
[docs] async def aparse(self, completion: str) -> T:
retries = 0
while retries <= self.max_retries:
try:
return await self.parser.aparse(completion)
except OutputParserException as e:
if retries == self.max_retries:
raise e
else:
retries += 1
completion = await self.retry_chain.arun(
instructions=self.parser.get_format_instructions(),
completion=completion,
error=repr(e),
)
raise OutputParserException("Failed to parse")
@property
def _type(self) -> str:
return "output_fixing"