路径验证器

Most ComfyUI errors are path errors wearing a different costume. A folder that moved, a filename typo, a directory that was supposed to be created by a previous run - they all fail somewhere downstream in a way that takes ten minutes to trace. Path Validator is the pack's pre-flight check: you give it a path, it tells you whether it exists, optionally creates missing folders for you, and counts the files inside. It turns "this will crash in the encode step" into a boolean you can gate on.

The node auto-detects whether a path is a file or a folder - using the filesystem when the path exists, and a heuristic (trailing slash or extension) when it doesn't - then reports three outputs:

• exists - BOOLEAN. The one you wire into a conditional/switch.
• path_out - the resolved full path (with any path_prefix applied) when it exists, empty when it doesn't.
• file_count - how many files are in a folder (respecting extension_filter), or -1 for files/non-directories/unreadable folders.

What you set

• path - file or folder path, absolute or relative.
• path_prefix - a directory prepended to relative paths. Handy when your paths are rooted at a common folder you don't want to repeat everywhere.
• create_if_missing - if the path is a folder and it doesn't exist, create it (default off). This is the "make sure the output dir is there before you write frames" trick.
• extension_filter - comma-separated extensions (png,jpg) for the count; empty counts everything.

When you'd reach for it

• Before a save node, verifying the output folder exists (and creating it if not).
• Before a loader, checking an input path is actually present so you can branch instead of crash.
• Confirming a folder has the expected number of frames before a video encode - the file_count output catches "wait, only 40 frames?" before it becomes a short silent video.

Install

Part of user2318/ComfyUI-CustomNodeKit. ComfyUI Manager: search "CustomNodeKit". Or:

cd ComfyUI/custom_nodes
git clone https://github.com/user2318/ComfyUI-CustomNodeKit.git
cd ComfyUI-CustomNodeKit
pip install -r requirements.txt

then restart. No models, no heavy deps - standard library os plus the pack base.

The gotcha

create_if_missing only works for directories. Point it at a missing file and it won't create anything (files need content, after all) - it just reports false. And the file/folder guess matters when the path doesn't exist yet: a path with no extension is treated as a folder, so a file you forgot to type the extension for will look like a missing directory, and file_count will be -1 rather than a helpful number. It's a validator, not a psychic - give it the path the way you'd actually use it, and it'll tell you the truth.