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langchain/langchain/memory/chat_memory.py

47 lines
1.6 KiB
Python

from abc import ABC
from typing import Any, Dict, List, Optional
from pydantic import BaseModel, Field
from langchain.memory.utils import get_prompt_input_key
from langchain.schema import AIMessage, BaseMemory, BaseMessage, HumanMessage
class ChatMessageHistory(BaseModel):
messages: List[BaseMessage] = Field(default_factory=list)
def add_user_message(self, message: str) -> None:
self.messages.append(HumanMessage(content=message))
def add_ai_message(self, message: str) -> None:
self.messages.append(AIMessage(content=message))
def clear(self) -> None:
self.messages = []
class BaseChatMemory(BaseMemory, ABC):
chat_memory: ChatMessageHistory = Field(default_factory=ChatMessageHistory)
output_key: Optional[str] = None
input_key: Optional[str] = None
return_messages: bool = False
def save_context(self, inputs: Dict[str, Any], outputs: Dict[str, str]) -> None:
"""Save context from this conversation to buffer."""
if self.input_key is None:
prompt_input_key = get_prompt_input_key(inputs, self.memory_variables)
else:
prompt_input_key = self.input_key
if self.output_key is None:
if len(outputs) != 1:
raise ValueError(f"One output key expected, got {outputs.keys()}")
output_key = list(outputs.keys())[0]
else:
output_key = self.output_key
self.chat_memory.add_user_message(inputs[prompt_input_key])
self.chat_memory.add_ai_message(outputs[output_key])
def clear(self) -> None:
"""Clear memory contents."""
self.chat_memory.clear()