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# `langchain_community.chat_message_histories.cassandra`.CassandraChatMessageHistory

class langchain_community.chat_message_histories.cassandra.CassandraChatMessageHistory(session_id: str, session: Optional[Session] = None, keyspace: Optional[str] = None, table_name: str = 'message_store', ttl_seconds: Optional[int] = None)

  Chat message history that stores history in Cassandra.

  Parameters

    - session_id (str) – arbitrary key that is used to store the messages of a single chat session.

    - session (Optional[Session]) – Cassandra driver session. If not provided, it is resolved from cassio.

    - keyspace (Optional[str]) – Cassandra key space. If not provided, it is resolved from cassio.

    - table_name (str) – name of the table to use.

    - ttl_seconds (Optional[int]) – time-to-live (seconds) for automatic expiration of stored entries. None (default) for no expiration.

  Attributes

  `messages` | Retrieve all session messages from DB

  Methods

  `__init__`(session_id[, session, keyspace, ...]) |
  `aadd_messages`(messages) | Add a list of messages.
  `aclear`() | Remove all messages from the store
  `add_ai_message`(message) | Convenience method for adding an AI message string to the store.
  `add_message`(message) | Write a message to the table
  `add_messages`(messages) | Add a list of messages.
  `add_user_message`(message) | Convenience method for adding a human message string to the store.
  `aget_messages`() | Async version of getting messages.
  `clear`() | Clear session memory from DB

  __init__(session_id: str, session: Optional[Session] = None, keyspace: Optional[str] = None, table_name: str = 'message_store', ttl_seconds: Optional[int] = None) → None
    Parameters

      - session_id (str) –

      - session (Optional[Session]) –

      - keyspace (Optional[str]) –

      - table_name (str) –

      - ttl_seconds (Optional[int]) –

    Return type

      None

  async aadd_messages(messages: Sequence[BaseMessage]) → None

    Add a list of messages.

    Parameters

      messages (Sequence[BaseMessage]) – A list of BaseMessage objects to store.

    Return type

      None

  async aclear() → None

    Remove all messages from the store

    Return type

      None

  add_ai_message(message: Union[AIMessage, str]) → None

    Convenience method for adding an AI message string to the store.

    Please note that this is a convenience method. Code should favor the bulk add_messages interface instead to save on round-trips to the underlying persistence layer.

    This method may be deprecated in a future release.

    Parameters

      message (Union[AIMessage, str]) – The AI message to add.

    Return type

      None

  add_message(message: BaseMessage) → None

    Write a message to the table

    Parameters

      message (BaseMessage) – A message to write.

    Return type

      None

  add_messages(messages: Sequence[BaseMessage]) → None

    Add a list of messages.

    Implementations should over-ride this method to handle bulk addition of messages in an efficient manner to avoid unnecessary round-trips to the underlying store.

    Parameters

      messages (Sequence[BaseMessage]) – A list of BaseMessage objects to store.

    Return type

      None

  add_user_message(message: Union[HumanMessage, str]) → None

    Convenience method for adding a human message string to the store.

    Please note that this is a convenience method. Code should favor the bulk add_messages interface instead to save on round-trips to the underlying persistence layer.

    This method may be deprecated in a future release.

    Parameters

      message (Union[HumanMessage, str]) – The human message to add

    Return type

      None

  async aget_messages() → List[BaseMessage]

    Async version of getting messages.

    Can over-ride this method to provide an efficient async implementation.

    In general, fetching messages may involve IO to the underlying persistence layer.

    Return type

      List[BaseMessage]

  clear() → None

    Clear session memory from DB

    Return type

      None

# Examples using CassandraChatMessageHistory

- Cassandra

- cassandra_chat_message_history.md