DictPromptTemplate Class — langchain Architecture

Source Code

libs/core/langchain_core/prompts/dict.py lines 18–97

class DictPromptTemplate(RunnableSerializable[dict, dict]):
    """Template represented by a dictionary.

    Recognizes variables in f-string or mustache formatted string dict values.

    Does NOT recognize variables in dict keys. Applies recursively.
    """

    template: dict[str, Any]
    template_format: Literal["f-string", "mustache"]

    @property
    def input_variables(self) -> list[str]:
        """Template input variables."""
        return _get_input_variables(self.template, self.template_format)

    def format(self, **kwargs: Any) -> dict[str, Any]:
        """Format the prompt with the inputs.

        Returns:
            A formatted dict.
        """
        return _insert_input_variables(self.template, kwargs, self.template_format)

    async def aformat(self, **kwargs: Any) -> dict[str, Any]:
        """Format the prompt with the inputs.

        Returns:
            A formatted dict.
        """
        return self.format(**kwargs)

    @override
    def invoke(
        self, input: dict, config: RunnableConfig | None = None, **kwargs: Any
    ) -> dict:
        return self._call_with_config(
            lambda x: self.format(**x),
            input,
            ensure_config(config),
            run_type="prompt",
            serialized=self._serialized,
            **kwargs,
        )

    @property
    def _prompt_type(self) -> str:
        return "dict-prompt"

    @cached_property
    def _serialized(self) -> dict[str, Any]:
        # self is always a Serializable object in this case, thus the result is
        # guaranteed to be a dict since dumpd uses the default callback, which uses
        # obj.to_json which always returns TypedDict subclasses
        return cast("dict[str, Any]", dumpd(self))

    @classmethod
    def is_lc_serializable(cls) -> bool:
        """Return `True` as this class is serializable."""
        return True

    @classmethod
    def get_lc_namespace(cls) -> list[str]:
        """Get the namespace of the LangChain object.

        Returns:
            `["langchain_core", "prompts", "dict"]`
        """
        return ["langchain_core", "prompts", "dict"]

    def pretty_repr(self, *, html: bool = False) -> str:
        """Human-readable representation.

        Args:
            html: Whether to format as HTML.

        Returns:
            Human-readable representation.
        """
        raise NotImplementedError