_validate_input() — langchain Function Reference

Source Code

libs/core/langchain_core/prompts/base.py lines 159–193

    def _validate_input(self, inner_input: Any) -> dict:
        if not isinstance(inner_input, dict):
            if len(self.input_variables) == 1:
                var_name = self.input_variables[0]
                inner_input_ = {var_name: inner_input}

            else:
                msg = (
                    f"Expected mapping type as input to {self.__class__.__name__}. "
                    f"Received {type(inner_input)}."
                )
                raise TypeError(
                    create_message(
                        message=msg, error_code=ErrorCode.INVALID_PROMPT_INPUT
                    )
                )
        else:
            inner_input_ = inner_input
        missing = set(self.input_variables).difference(inner_input_)
        if missing:
            msg = (
                f"Input to {self.__class__.__name__} is missing variables {missing}. "
                f" Expected: {self.input_variables}"
                f" Received: {list(inner_input_.keys())}"
            )
            example_key = missing.pop()
            msg += (
                f"\nNote: if you intended {{{example_key}}} to be part of the string"
                " and not a variable, please escape it with double curly braces like: "
                f"'{{{{{example_key}}}}}'."
            )
            raise KeyError(
                create_message(message=msg, error_code=ErrorCode.INVALID_PROMPT_INPUT)
            )
        return inner_input_