After trying out in my PDI, I am able to achieve this partially so far:

Using Business rules, this is what can be done:

• Check the contents of the main zip file (no nesting of zips - zip files within zip file)
• unable to save the files from the ZipEntry into sys_attachment (therefore only I cant check further than 1 level of zip nesting)
• Check file extensions without saving any of the file contents in sys_attachment
• Unable to validate the MIME of the file contents - can't find any external MIME library that will work in a Business rule/script include
• Check folders and nested folders in the zip file

If using flow designer's "Zip step" action, it should be possible to unzip more than 1 level of zip files, as I can save the zip contents into sys_attachment records for further processing, and the file extensions are checked against glide.attachment.extensions before saving.

One limitation I found is that unzipping the zip file using flow designer does not do any MIME-check when saving the file contents into sys_attachment, so files saved in this way will bypass SN's MIME-check, meaning MIME validation of zip file contents is still not possible so far from what I have tried.

Also, this Zip step will require IntegrationHub Professional, which I do not have.

If anyone is able to validate MIME-type of zip file contents and/or also save the contents in sys_attachment via business rules, I will appreciate greatly if you can share your experience in doing so.

Regards,

Wei