NIFI-16000: Allow spaces in FileUtils.getSanitizedFilename

[mcgilman]

Remove the space character from the invalid-character set so interior spaces are preserved, and normalize the result by collapsing whitespace runs to a single space and stripping leading/trailing whitespace and trailing dots. This lets the asset-upload callers accept common valid filenames such as "driver (1).jar" while still rejecting non-canonical names. Add TestFileUtils covering the sanitization contract.

Summary

NIFI-16000

FileUtils.getSanitizedFilename(String) treats the space character (code point 32) as invalid and replaces it with an underscore. The space character is legal on every major file system (NTFS, ext4, APFS, etc.), so this is stricter than necessary.

This matters because of how the method is consumed. Both ConnectorResource and ParameterContextResource use it as a strict validation gate for the asset name supplied in the Filename request header — they sanitize the supplied name and reject the request if the sanitized value differs from the original:

final String sanitizedAssetName = FileUtils.getSanitizedFilename(assetName);
if (!assetName.equals(sanitizedAssetName)) {
    throw new IllegalArgumentException(FILENAME_HEADER + " header contains an invalid file name");
}

Because any name containing a space is rewritten during sanitization, the equality check fails and the upload is rejected. As a result, common valid filenames cannot be uploaded as assets — e.g. a file produced by browser/OS download de-duplication such as driver (1).jar is sanitized to driver_(1).jar and rejected with "... header contains an invalid file name."

Changes

• Removed the space character (32) from the invalid-character set so spaces are preserved rather than replaced.
• Spaces are kept exactly as supplied (leading, trailing, repeated, and interior); no other normalization is performed. All other characters continue to be sanitized as before.
• Added TestFileUtils covering the sanitization contract (null/empty, invalid-character replacement, spaces preserved, dots preserved).

The change is backward compatible: any filename that contained no spaces is sanitized exactly as before. The only behavioral change is that the space character is now preserved instead of replaced, so filenames whose sole issue was a space are now accepted by the asset-upload callers instead of being rejected.

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  • JDK 21

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