call() — langchain Function Reference

Architecture documentation for the __call__() function in load.py from the langchain codebase.

Function python LangChainCore ApiManagement

Entity Profile

LangChainCore→ ApiManagement→ __call__() — langchain Function Reference

Dependency Diagram

graph TD
  7bf2809f_6b72_455d_041e_15ac52a675c5["__call__()"]
  717df861_44bf_d747_e788_3195caa42d87["Reviver"]
  7bf2809f_6b72_455d_041e_15ac52a675c5 -->|defined in| 717df861_44bf_d747_e788_3195caa42d87
  style 7bf2809f_6b72_455d_041e_15ac52a675c5 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/load/load.py lines 361–470

    def __call__(self, value: dict[str, Any]) -> Any:
        """Revive the value.

        Args:
            value: The value to revive.

        Returns:
            The revived value.

        Raises:
            ValueError: If the namespace is invalid.
            ValueError: If trying to deserialize something that cannot
                be deserialized in the current version of langchain-core.
            NotImplementedError: If the object is not implemented and
                `ignore_unserializable_fields` is False.
        """
        if (
            value.get("lc") == 1
            and value.get("type") == "secret"
            and value.get("id") is not None
        ):
            [key] = value["id"]
            if key in self.secrets_map:
                return self.secrets_map[key]
            if self.secrets_from_env and key in os.environ and os.environ[key]:
                return os.environ[key]
            return None

        if (
            value.get("lc") == 1
            and value.get("type") == "not_implemented"
            and value.get("id") is not None
        ):
            if self.ignore_unserializable_fields:
                return None
            msg = (
                "Trying to load an object that doesn't implement "
                f"serialization: {value}"
            )
            raise NotImplementedError(msg)

        if (
            value.get("lc") == 1
            and value.get("type") == "constructor"
            and value.get("id") is not None
        ):
            [*namespace, name] = value["id"]
            mapping_key = tuple(value["id"])

            if (
                self.allowed_class_paths is not None
                and mapping_key not in self.allowed_class_paths
            ):
                msg = (
                    f"Deserialization of {mapping_key!r} is not allowed. "
                    "The default (allowed_objects='core') only permits core "
                    "langchain-core classes. To allow trusted partner integrations, "
                    "use allowed_objects='all'. Alternatively, pass an explicit list "
                    "of allowed classes via allowed_objects=[...]. "
                    "See langchain_core.load.mapping for the full allowlist."
                )
                raise ValueError(msg)

            if (
                namespace[0] not in self.valid_namespaces
                # The root namespace ["langchain"] is not a valid identifier.
                or namespace == ["langchain"]
            ):
                msg = f"Invalid namespace: {value}"
                raise ValueError(msg)
            # Determine explicit import path
            if mapping_key in self.import_mappings:
                import_path = self.import_mappings[mapping_key]
                # Split into module and name
                import_dir, name = import_path[:-1], import_path[-1]
            elif namespace[0] in DISALLOW_LOAD_FROM_PATH:
                msg = (
                    "Trying to deserialize something that cannot "
                    "be deserialized in current version of langchain-core: "
                    f"{mapping_key}."
                )