✨ feat(custom): add custom component interface and base classes

🔧 chore(custom): create a custom component creator class to handle custom component creation and loading

The commit adds two new files: `__init__.py` and `base.py` under the `src/backend/langflow/interface/custom` directory. The `__init__.py` file imports the `CustomComponentCreator` and `CustomComponent` classes from the `base.py` file. The `base.py` file defines the `CustomComponentCreator` class, which is responsible for creating and loading custom components. It also includes necessary imports and a `CustomComponentFrontendNode` class.

The addition of these files is necessary to support custom components in the application. The `CustomComponentCreator` class provides a way to create and load custom components, and the `CustomComponent` class represents a custom component. This allows for the dynamic creation and usage of custom components in the application.

src/backend/langflow/interface/custom/__init__.py

@@ -0,0 +1,4 @@
+from langflow.interface.custom.base import CustomComponentCreator
+from langflow.interface.custom.custom import CustomComponent
+
+__all__ = ["CustomComponentCreator", "CustomComponent"]

src/backend/langflow/interface/custom/base.py

@@ -0,0 +1,43 @@
+from typing import Any, Dict, List, Optional, Type
+
+from langflow.custom.customs import get_custom_nodes
+from langflow.interface.base import LangChainTypeCreator
+from langflow.interface.custom.custom import CustomComponent
+from langflow.template.frontend_node.custom_components import (
+    CustomComponentFrontendNode,
+)
+from langflow.utils.logger import logger
+
+# Assuming necessary imports for Field, Template, and FrontendNode classes
+
+
+class CustomComponentCreator(LangChainTypeCreator):
+    type_name: str = "custom_components"
+
+    @property
+    def frontend_node_class(self) -> Type[CustomComponentFrontendNode]:
+        return CustomComponentFrontendNode
+
+    @property
+    def type_to_loader_dict(self) -> Dict:
+        if self.type_dict is None:
+            self.type_dict: dict[str, Any] = {
+                "CustomComponent": CustomComponent,
+            }
+        return self.type_dict
+
+    def get_signature(self, name: str) -> Optional[Dict]:
+        try:
+            if name in get_custom_nodes(self.type_name).keys():
+                return get_custom_nodes(self.type_name)[name]
+        except ValueError as exc:
+            raise ValueError(f"CustomComponent {name} not found: {exc}") from exc
+        except AttributeError as exc:
+            logger.error(f"CustomComponent {name} not loaded: {exc}")
+            return None
+
+    def to_list(self) -> List[str]:
+        return list(self.type_to_loader_dict.keys())
+
+
+custom_component_creator = CustomComponentCreator()