nit

app/frontend_management.py

@@ -31,12 +31,12 @@ def frontend_install_warning_message():
     return f"Please install the updated requirements.txt file by running:\n{sys.executable} {extra}-m pip install -r {req_path}\n\nThis error is happening because the ComfyUI frontend is no longer shipped as part of the main repo but as a pip package instead.\n\nIf you are on the portable package you can run: update\\update_comfyui.bat to solve this problem"
 
 
+def parse_version(version: str) -> tuple[int, int, int]:
+    return tuple(map(int, version.split(".")))
+
+
 def check_frontend_version():
     """Check if the frontend version is up to date."""
-
-    def parse_version(version: str) -> tuple[int, int, int]:
-        return tuple(map(int, version.split(".")))
-
     try:
         frontend_version_str = version("comfyui-frontend-package")
         frontend_version = parse_version(frontend_version_str)
@@ -73,6 +73,11 @@ class FrontEndProvider:
     owner: str
     repo: str
 
+    @property
+    def is_official(self) -> bool:
+        """Check if the provider is the default official one."""
+        return self.owner == "Comfy-Org" and self.repo == "ComfyUI_frontend"
+
     @property
     def folder_name(self) -> str:
         return f"{self.owner}_{self.repo}"
@@ -143,14 +148,24 @@ def download_release_asset_zip(release: Release, destination_path: str) -> None:
             zip_ref.extractall(destination_path)
 
 
+class FrontendInit(TypedDict):
+    web_root: str
+    """ The path to the initialized frontend. """
+    version: tuple[int, int, int] | None
+    """ The version of the initialized frontend. None for unrecognized version."""
+
 class FrontendManager:
     CUSTOM_FRONTENDS_ROOT = str(Path(__file__).parents[1] / "web_custom_versions")
 
     @classmethod
-    def default_frontend_path(cls) -> str:
+    def init_default_frontend(cls) -> FrontendInit:
+        check_frontend_version()
         try:
             import comfyui_frontend_package
-            return str(importlib.resources.files(comfyui_frontend_package) / "static")
+            return FrontendInit(
+                web_root=str(importlib.resources.files(comfyui_frontend_package) / "static"),
+                version=parse_version(version("comfyui-frontend-package")),
+            )
         except ImportError:
             logging.error(f"\n\n********** ERROR ***********\n\ncomfyui-frontend-package is not installed. {frontend_install_warning_message()}\n********** ERROR **********\n")
             sys.exit(-1)
@@ -175,7 +190,7 @@ class FrontendManager:
         return match_result.group(1), match_result.group(2), match_result.group(3)
 
     @classmethod
-    def init_frontend_unsafe(cls, version_string: str, provider: Optional[FrontEndProvider] = None) -> str:
+    def init_frontend_unsafe(cls, version_string: str, provider: Optional[FrontEndProvider] = None) -> FrontendInit:
         """
         Initializes the frontend for the specified version.
 
@@ -191,8 +206,7 @@ class FrontendManager:
             main error source might be request timeout or invalid URL.
         """
         if version_string == DEFAULT_VERSION_STRING:
-            check_frontend_version()
+            return cls.init_default_frontend()
-            return cls.default_frontend_path()
 
         repo_owner, repo_name, version = cls.parse_version_string(version_string)
 
@@ -227,10 +241,13 @@ class FrontendManager:
                 if not os.listdir(web_root):
                     os.rmdir(web_root)
 
-        return web_root
+        return FrontendInit(
+            web_root=web_root,
+            version=parse_version(semantic_version) if provider.is_official else None,
+        )
 
     @classmethod
-    def init_frontend(cls, version_string: str) -> str:
+    def init_frontend(cls, version_string: str) -> FrontendInit:
         """
         Initializes the frontend with the specified version string.
 
@@ -245,5 +262,4 @@ class FrontendManager:
         except Exception as e:
             logging.error("Failed to initialize frontend: %s", e)
             logging.info("Falling back to the default frontend.")
-            check_frontend_version()
+            return cls.init_default_frontend()
-            return cls.default_frontend_path()

comfy/comfy_types/node_typing.py

@@ -220,6 +220,13 @@ class ComfyNodeABC(ABC):
     """Flags a node as experimental, informing users that it may change or not work as expected."""
     DEPRECATED: bool
     """Flags a node as deprecated, indicating to users that they should find alternatives to this node."""
+    REQUIRED_FRONTEND_VERSION: str | None
+    """The minimum version of the ComfyUI frontend required to load this node.
+
+    Usage::
+
+        REQUIRED_FRONTEND_VERSION = "1.9.7"
+    """
 
     @classmethod
     @abstractmethod

server.py

@@ -1,3 +1,4 @@
+from __future__ import annotations
 import os
 import sys
 import asyncio
@@ -24,11 +25,12 @@ import logging
 
 import mimetypes
 from comfy.cli_args import args
+from comfy.comfy_types.node_typing import ComfyNodeABC
 import comfy.utils
 import comfy.model_management
 import node_helpers
 from comfyui_version import __version__
-from app.frontend_management import FrontendManager
+from app.frontend_management import FrontendInit, FrontendManager, parse_version
 from app.user_manager import UserManager
 from app.model_manager import ModelFileManager
 from app.custom_node_manager import CustomNodeManager
@@ -146,6 +148,11 @@ def create_origin_only_middleware():
     return origin_only_middleware
 
 class PromptServer():
+    web_root: str
+    """The path to the initialized frontend assets."""
+    frontend_version: tuple[int, int, int] | None = None
+    """The version of the initialized frontend. None for unrecognized version."""
+
     def __init__(self, loop):
         PromptServer.instance = self
 
@@ -176,12 +183,19 @@ class PromptServer():
         max_upload_size = round(args.max_upload_size * 1024 * 1024)
         self.app = web.Application(client_max_size=max_upload_size, middlewares=middlewares)
         self.sockets = dict()
-        self.web_root = (
+
-            FrontendManager.init_frontend(args.front_end_version)
+        if args.front_end_root:
-            if args.front_end_root is None
+            frontend_init = FrontendInit(
-            else args.front_end_root
+                web_root=args.front_end_root,
-        )
+                version=None,
+            )
+        else:
+            frontend_init = FrontendManager.init_frontend(args.front_end_version)
+
+        self.frontend_version = frontend_init["version"]
+        self.web_root = frontend_init["web_root"]
         logging.info(f"[Prompt Server] web root: {self.web_root}")
+
         routes = web.RouteTableDef()
         self.routes = routes
         self.last_node_id = None
@@ -587,6 +601,9 @@ class PromptServer():
             with folder_paths.cache_helper:
                 out = {}
                 for x in nodes.NODE_CLASS_MAPPINGS:
+                    if not self.node_is_supported(x):
+                        continue
+
                     try:
                         out[x] = node_info(x)
                     except Exception:
@@ -598,7 +615,11 @@ class PromptServer():
         async def get_object_info_node(request):
             node_class = request.match_info.get("node_class", None)
             out = {}
-            if (node_class is not None) and (node_class in nodes.NODE_CLASS_MAPPINGS):
+            if (
+                node_class is not None
+                and node_class in nodes.NODE_CLASS_MAPPINGS
+                and self.node_is_supported(node_class)
+            ):
                 out[node_class] = node_info(node_class)
             return web.json_response(out)
 
@@ -863,3 +884,15 @@ class PromptServer():
                 logging.warning(traceback.format_exc())
 
         return json_data
+
+    def node_is_supported(self, node_class: ComfyNodeABC) -> bool:
+        """Check if the node is supported by the frontend."""
+        # For unrecognized frontend version, we assume the node is supported.
+        if self.frontend_version is None:
+            return True
+
+        # Check if the node is supported by the frontend.
+        if node_class.REQUIRED_FRONTEND_VERSION is None:
+            return True
+
+        return parse_version(node_class.REQUIRED_FRONTEND_VERSION) <= self.frontend_version

tests-unit/app_test/frontend_manager_test.py

@@ -69,8 +69,10 @@ def test_get_release_invalid_version(mock_provider):
 
 def test_init_frontend_default():
     version_string = DEFAULT_VERSION_STRING
-    frontend_path = FrontendManager.init_frontend(version_string)
+    frontend_init = FrontendManager.init_frontend(version_string)
-    assert frontend_path == FrontendManager.default_frontend_path()
+    assert isinstance(frontend_init, dict)
+    assert "web_root" in frontend_init
+    assert "version" in frontend_init
 
 
 def test_init_frontend_invalid_version():
@@ -138,37 +140,47 @@ def test_parse_version_string_invalid():
 def test_init_frontend_default_with_mocks():
     # Arrange
     version_string = DEFAULT_VERSION_STRING
+    mock_path = "/mocked/path"
+    mock_version = (1, 0, 0)
 
     # Act
     with (
         patch("app.frontend_management.check_frontend_version") as mock_check,
         patch.object(
-            FrontendManager, "default_frontend_path", return_value="/mocked/path"
+            FrontendManager,
+            "init_default_frontend",
+            return_value={"web_root": mock_path, "version": mock_version},
         ),
     ):
-        frontend_path = FrontendManager.init_frontend(version_string)
+        frontend_init = FrontendManager.init_frontend(version_string)
 
     # Assert
-    assert frontend_path == "/mocked/path"
+    assert frontend_init["web_root"] == mock_path
-    mock_check.assert_called_once()
+    assert frontend_init["version"] == mock_version
+    mock_check.assert_not_called()  # check_frontend_version is now called inside init_default_frontend
 
 
 def test_init_frontend_fallback_on_error():
     # Arrange
     version_string = "test-owner/test-repo@1.0.0"
+    mock_path = "/default/path"
+    mock_version = (1, 0, 0)
 
     # Act
     with (
         patch.object(
-            FrontendManager, "init_frontend_unsafe", side_effect=Exception("Test error")
+            FrontendManager,
+            "init_frontend_unsafe",
+            side_effect=Exception("Test error")
         ),
-        patch("app.frontend_management.check_frontend_version") as mock_check,
         patch.object(
-            FrontendManager, "default_frontend_path", return_value="/default/path"
+            FrontendManager,
+            "init_default_frontend",
+            return_value={"web_root": mock_path, "version": mock_version},
         ),
     ):
-        frontend_path = FrontendManager.init_frontend(version_string)
+        frontend_init = FrontendManager.init_frontend(version_string)
 
     # Assert
-    assert frontend_path == "/default/path"
+    assert frontend_init["web_root"] == mock_path
-    mock_check.assert_called_once()
+    assert frontend_init["version"] == mock_version