feat: add ProjectKey single-output relay node

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

project_loader.py

@@ -231,13 +231,61 @@ class ProjectSource:
         return ()
 
 
+class ProjectKey:
+    """Single-output relay — fetches one key from a ProjectSource."""
+    @classmethod
+    def INPUT_TYPES(s):
+        return {
+            "required": {
+                "source_label": ("STRING", {"default": "", "multiline": False}),
+                "key_name": ("STRING", {"default": "", "multiline": False}),
+                "key_type": ("STRING", {"default": "STRING", "multiline": False}),
+            },
+            "optional": {
+                "manager_url": ("STRING", {"default": "http://localhost:8080", "multiline": False}),
+                "project_name": ("STRING", {"default": "", "multiline": False}),
+                "file_name": ("STRING", {"default": "", "multiline": False}),
+                "sequence_number": ("INT", {"default": 1, "min": 1, "max": 9999}),
+            },
+        }
+
+    RETURN_TYPES = (any_type,)
+    RETURN_NAMES = ("value",)
+    FUNCTION = "fetch_key"
+    CATEGORY = "utils/json/project"
+    OUTPUT_NODE = False
+
+    def fetch_key(self, source_label, key_name, key_type,
+                  manager_url="http://localhost:8080", project_name="",
+                  file_name="", sequence_number=1):
+        data = _fetch_data(manager_url, project_name, file_name, sequence_number)
+        if data.get("error") in ("http_error", "network_error", "parse_error"):
+            msg = data.get("message", "Unknown error")
+            raise RuntimeError(f"Failed to fetch data: {msg}")
+
+        val = data.get(key_name, "")
+
+        if key_type == "INT":
+            return (to_int(val),)
+        elif key_type == "FLOAT":
+            return (to_float(val),)
+        elif isinstance(val, bool):
+            return (str(val).lower(),)
+        elif isinstance(val, (int, float)):
+            return (val,)
+        else:
+            return (str(val),)
+
+
 # --- Mappings ---
 PROJECT_NODE_CLASS_MAPPINGS = {
     "ProjectLoaderDynamic": ProjectLoaderDynamic,
     "ProjectSource": ProjectSource,
+    "ProjectKey": ProjectKey,
 }
 
 PROJECT_NODE_DISPLAY_NAME_MAPPINGS = {
     "ProjectLoaderDynamic": "Project Loader (Dynamic)",
     "ProjectSource": "Project Source",
+    "ProjectKey": "Project Key",
 }

tests/test_project_loader.py

@@ -235,9 +235,108 @@ class TestProjectSource:
         assert ProjectSource.CATEGORY == "utils/json/project"
 
 
+class TestProjectKey:
+    def test_input_types(self):
+        from project_loader import ProjectKey
+        inputs = ProjectKey.INPUT_TYPES()
+        assert "source_label" in inputs["required"]
+        assert "key_name" in inputs["required"]
+        assert "key_type" in inputs["required"]
+
+    def test_single_output(self):
+        from project_loader import ProjectKey
+        assert len(ProjectKey.RETURN_TYPES) == 1
+        assert len(ProjectKey.RETURN_NAMES) == 1
+
+    def test_fetch_key_string(self):
+        from project_loader import ProjectKey
+        node = ProjectKey()
+        data = {"prompt": "hello", "seed": 42}
+        with patch("project_loader._fetch_data", return_value=data):
+            result = node.fetch_key(
+                source_label="my_source",
+                key_name="prompt",
+                key_type="STRING",
+                manager_url="http://localhost:8080",
+                project_name="proj1",
+                file_name="batch_i2v",
+                sequence_number=1,
+            )
+        assert result == ("hello",)
+
+    def test_fetch_key_int_coercion(self):
+        from project_loader import ProjectKey
+        node = ProjectKey()
+        data = {"seed": "42"}
+        with patch("project_loader._fetch_data", return_value=data):
+            result = node.fetch_key(
+                source_label="my_source",
+                key_name="seed",
+                key_type="INT",
+                manager_url="http://localhost:8080",
+                project_name="proj1",
+                file_name="batch_i2v",
+                sequence_number=1,
+            )
+        assert result == (42,)
+
+    def test_fetch_key_float_coercion(self):
+        from project_loader import ProjectKey
+        node = ProjectKey()
+        data = {"cfg": "1.5"}
+        with patch("project_loader._fetch_data", return_value=data):
+            result = node.fetch_key(
+                source_label="my_source",
+                key_name="cfg",
+                key_type="FLOAT",
+                manager_url="http://localhost:8080",
+                project_name="proj1",
+                file_name="batch_i2v",
+                sequence_number=1,
+            )
+        assert result == (1.5,)
+
+    def test_fetch_key_missing_key(self):
+        from project_loader import ProjectKey
+        node = ProjectKey()
+        with patch("project_loader._fetch_data", return_value={}):
+            result = node.fetch_key(
+                source_label="my_source",
+                key_name="nonexistent",
+                key_type="STRING",
+                manager_url="http://localhost:8080",
+                project_name="proj1",
+                file_name="batch_i2v",
+                sequence_number=1,
+            )
+        assert result == ("",)
+
+    def test_fetch_key_network_error(self):
+        from project_loader import ProjectKey
+        node = ProjectKey()
+        error_resp = {"error": "network_error", "message": "Connection refused"}
+        with patch("project_loader._fetch_data", return_value=error_resp):
+            with pytest.raises(RuntimeError, match="Failed to fetch"):
+                node.fetch_key(
+                    source_label="my_source",
+                    key_name="prompt",
+                    key_type="STRING",
+                    manager_url="http://localhost:8080",
+                    project_name="proj1",
+                    file_name="batch_i2v",
+                    sequence_number=1,
+                )
+
+    def test_category(self):
+        from project_loader import ProjectKey
+        assert ProjectKey.CATEGORY == "utils/json/project"
+
+
 class TestNodeMappings:
     def test_mappings_exist(self):
         from project_loader import PROJECT_NODE_CLASS_MAPPINGS, PROJECT_NODE_DISPLAY_NAME_MAPPINGS
         assert "ProjectLoaderDynamic" in PROJECT_NODE_CLASS_MAPPINGS
-        assert len(PROJECT_NODE_CLASS_MAPPINGS) == 1
+        assert "ProjectSource" in PROJECT_NODE_CLASS_MAPPINGS
-        assert len(PROJECT_NODE_DISPLAY_NAME_MAPPINGS) == 1
+        assert "ProjectKey" in PROJECT_NODE_CLASS_MAPPINGS
+        assert len(PROJECT_NODE_CLASS_MAPPINGS) == 3
+        assert len(PROJECT_NODE_DISPLAY_NAME_MAPPINGS) == 3