[BUG] S3 Directory Loader fails when prefix is a directory (e.g. docs or docs/) – EISDIR error #4688

Describe the bug
When configuring an S3 Directory Loader, Flowise refuses prefixes that end with a trailing slash (e.g. docs/). It only accepts prefixes like docs/1, and then processes only the objects whose keys start with that extra character. Attempting to use a bare folder prefix results in an error:

Failed to preview chunks: Error: documentStoreServices.previewChunksMiddleware - Error: documentStoreServices.previewChunks - Error: documentStoreServices.splitIntoChunks - Failed to load data from bucket my-bucket: Failed to download file docs/ from S3 bucket my-bucket: EISDIR: illegal operation on a directory, open '/tmp/s3fileloader-DlNmPf/docs/'

To Reproduce
Steps to reproduce the behavior:

Go to Data Sources → New Loader → S3 Directory Loader.
Enter any valid bucket name
Set your prefix (docs/ in my case)
Click Preview
See the error above.

Expected behavior
Flowise should traverse the entire folder (docs/) and process every object inside it, without requiring an additional character after the trailing slash.

Setup

• Installation: docker
• Flowise Version: 3.0.1
• OS: Windows 11
• Browser: Google Chrome

Additional context
Flowise should traverse the entire folder (docs/) and process every object inside it, without requiring an additional character after the trailing slash.