Source code for langchain.memory.buffer
from typing import Any, Dict, List, Optional
from pydantic import root_validator
from langchain.memory.chat_memory import BaseChatMemory, BaseMemory
from langchain.memory.utils import get_prompt_input_key
from langchain.schema import get_buffer_string
[docs]class ConversationBufferMemory(BaseChatMemory):
    """Buffer for storing conversation memory."""
    human_prefix: str = "Human"
    ai_prefix: str = "AI"
    memory_key: str = "history"  #: :meta private:
    @property
    def buffer(self) -> Any:
        """String buffer of memory."""
        if self.return_messages:
            return self.chat_memory.messages
        else:
            return get_buffer_string(
                self.chat_memory.messages,
                human_prefix=self.human_prefix,
                ai_prefix=self.ai_prefix,
            )
    @property
    def memory_variables(self) -> List[str]:
        """Will always return list of memory variables.
        :meta private:
        """
        return [self.memory_key]
[docs]    def load_memory_variables(self, inputs: Dict[str, Any]) -> Dict[str, Any]:
        """Return history buffer."""
        return {self.memory_key: self.buffer}
[docs]class ConversationStringBufferMemory(BaseMemory):
    """Buffer for storing conversation memory."""
    human_prefix: str = "Human"
    ai_prefix: str = "AI"
    """Prefix to use for AI generated responses."""
    buffer: str = ""
    output_key: Optional[str] = None
    input_key: Optional[str] = None
    memory_key: str = "history"  #: :meta private:
    @root_validator()
    def validate_chains(cls, values: Dict) -> Dict:
rtdocs_stable/api.python.langchain.com/en/stable/_modules/langchain/memory/buffer.html