load_memory_variables() — langchain Function Reference

Source Code

libs/langchain/langchain_classic/memory/vectorstore_token_buffer_memory.py lines 123–143

    def load_memory_variables(self, inputs: dict[str, Any]) -> dict[str, Any]:
        """Return history and memory buffer."""
        try:
            with warnings.catch_warnings():
                warnings.simplefilter("ignore")
                memory_variables = self.memory_retriever.load_memory_variables(inputs)
            previous_history = memory_variables[self.memory_retriever.memory_key]
        except AssertionError:  # happens when db is empty
            previous_history = ""
        current_history = super().load_memory_variables(inputs)
        template = SystemMessagePromptTemplate.from_template(
            self.previous_history_template,
        )
        messages = [
            template.format(
                previous_history=previous_history,
                current_time=datetime.now().astimezone().strftime(TIMESTAMP_FORMAT),
            ),
        ]
        messages.extend(current_history[self.memory_key])
        return {self.memory_key: messages}