Sanitize Filename (Oli)

Sanitize Filename (Oli) takes a string - a prompt, a title, a generated tag - and turns it into something Windows, macOS, and your save node will all accept. It's the boring-but-necessary node you reach for the first time a generated file fails to write because the filename contained a /, a :, or a control character that made the OS (or your importer) throw up.

How it works

It's a whitelist filter, not a "remove the bad characters I know about" filter. Anything that isn't explicitly allowed gets replaced:

• ASCII letters and digits always survive.
• Hyphens survive.
• Spaces survive if allow_spaces is on (default).
• Forward slashes survive if allow_slash is on (default) - treated as path separators, so a "folder/file" input builds a real subpath.
• Unicode survives only if allow_unicode is on. Off (the default), diacritics are transliterated via NFKD: à→a, é→e, ü→u, ñ→n. Characters with no ASCII decomposition get dropped.

Everything else becomes replacement (default _; must be a single non-alphanumeric ASCII character - invalid values fall back to _). Runs of two or more separators collapse to the highest-priority one (/ > - > space > replacement), so a messy name doesn't become a run of underscores. It also normalizes backslashes to forward slashes, trims junk from the edges, and truncates to a byte limit.

Inputs that matter

• filename - the name to sanitize (may include / separators).
• folder - an optional prefix path; slashes are always allowed here.
• extension - with or without the leading dot; it's stripped and re-added cleanly.
• max_length - caps the filename component at N UTF-8 bytes (default 240). The default deliberately leaves room for the counter and extension that save nodes append - the OS limit is 255 bytes. Note it's bytes, not characters, so accented letters (2 bytes each) count double.
• replacement - the substitution character.

Outputs

Three strings, so you can feed whichever a save node wants: prefix (folder/filename without the extension - the thing Save Image-style nodes take), path (folder/filename.ext), and filename (just filename.ext, no folder).

Install & gotchas

cd ComfyUI/custom_nodes
git clone https://github.com/magicoli/comfyui-oli-prompt-tools

…or ComfyUI Manager → Oli Prompt Tools, then restart. No dependencies.

It's one of the pack's newer nodes, so it's missing from the README's node table - it loads fine, the docs just lag the code. And a friendly warning: because allow_unicode defaults to off, a filename full of non-Latin script loses most of its characters. If your prompts are in Japanese or Arabic, turn allow_unicode on or you'll end up with a pile of underscores.