Add set extension node

README.md

@@ -158,6 +158,7 @@ These nodes are very lightweight and require no additional dependencies.
     - is_absolute - Checks if a path is absolute (begins at root directory)
     - get_size - Returns the size of a file in bytes
     - get_extension - Extracts the file extension from a path (including the dot)
+    - set_extension - Replaces or adds a file extension to a path
 - Directory operations:
     - list_dir - Lists files and directories in a specified path with filtering options
     - get_cwd - Returns the current working directory

src/basic_data_handling/path_nodes.py

@@ -453,6 +453,37 @@ class PathNormalize(ComfyNodeABC):
         return (os.path.normpath(path),)
 
 
+class PathSetExtension(ComfyNodeABC):
+    """
+    Sets the file extension for a path.
+
+    This node replaces the current extension in a path with a new one.
+    The extension should include the dot (e.g., '.jpg').
+    """
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "path": (IO.STRING, {}),
+                "extension": (IO.STRING, {"default": ".txt"}),
+            }
+        }
+
+    RETURN_TYPES = (IO.STRING,)
+    RETURN_NAMES = ("path",)
+    CATEGORY = "Basic/Path"
+    DESCRIPTION = cleandoc(__doc__ or "")
+    FUNCTION = "set_extension"
+
+    def set_extension(self, path: str, extension: str) -> tuple[str]:
+        # Make sure extension starts with a dot
+        if not extension.startswith('.') and extension:
+            extension = '.' + extension
+
+        root, _ = os.path.splitext(path)
+        return (root + extension,)
+
+
 class PathRelative(ComfyNodeABC):
     """
     Returns a relative path.
@@ -542,6 +573,7 @@ NODE_CLASS_MAPPINGS = {
     "Basic data handling: PathExpandVars": PathExpandVars,
     "Basic data handling: PathGetCwd": PathGetCwd,
     "Basic data handling: PathGetExtension": PathGetExtension,
+    "Basic data handling: PathSetExtension": PathSetExtension,
     "Basic data handling: PathGetSize": PathGetSize,
     "Basic data handling: PathGlob": PathGlob,
     "Basic data handling: PathIsAbsolute": PathIsAbsolute,
@@ -564,6 +596,7 @@ NODE_DISPLAY_NAME_MAPPINGS = {
     "Basic data handling: PathExpandVars": "expand vars",
     "Basic data handling: PathGetCwd": "get current working directory",
     "Basic data handling: PathGetExtension": "get extension",
+    "Basic data handling: PathSetExtension": "set extension",
     "Basic data handling: PathGetSize": "get size",
     "Basic data handling: PathGlob": "glob",
     "Basic data handling: PathIsAbsolute": "is absolute",

tests/test_path_nodes.py

@@ -5,7 +5,7 @@ import platform
 from src.basic_data_handling.path_nodes import (
     PathJoin, PathAbspath, PathExists, PathIsFile, PathIsDir, PathGetSize,
     PathSplit, PathSplitExt, PathBasename, PathDirname, PathGetExtension,
-    PathNormalize, PathRelative, PathGlob, PathExpandVars, PathGetCwd,
+    PathSetExtension, PathNormalize, PathRelative, PathGlob, PathExpandVars, PathGetCwd,
     PathListDir, PathIsAbsolute, PathCommonPrefix,
 )
 
@@ -199,6 +199,24 @@ def test_path_get_extension():
     # Test with empty string
     assert node.get_extension("") == ("",)
 
+def test_path_set_extension():
+    node = PathSetExtension()
+    # Test basic extension replacement
+    assert node.set_extension("file.txt", ".jpg") == ("file.jpg",)
+    # Test adding extension to file without extension
+    assert node.set_extension("file", ".png") == ("file.png",)
+    # Test with extension without dot prefix
+    assert node.set_extension("document.docx", "pdf") == ("document.pdf",)
+    # Test with path containing directory
+    assert node.set_extension("folder/image.jpg", ".png") == ("folder/image.png",)
+    # Test with multiple dots in filename
+    assert node.set_extension("archive.tar.gz", ".zip") == ("archive.tar.zip",)
+    # Test with empty extension (removes extension)
+    assert node.set_extension("config.ini", "") == ("config",)
+    # Test with empty string as path
+    assert node.set_extension("", ".txt") == (".txt",)
+
+
 
 def test_path_normalize():
     node = PathNormalize()