# Files in and out

- Files come in as base64 (books.attach_receipt, books.file_document), or, for a file already on this computer, with books.import_local_file: an absolute path to a regular file in the server's import folders (by default your downloads folder). Save the file there first; files of the books themselves are never read, and a path that is missing or outside the import folders gets one refusal, whatever is there.
- A W-9 given by path (books.set_w9 w9_file_path) is read the same way.
- Files holding full TINs (books.get_w9, books.vendor_1099 with include_tins, books.export_cpa_package with TINs) are never saved in the import folders. No file with a full TIN goes into the books, however it is filed: the server refuses every file it read or wrote with full TINs (the W-9 books.set_w9 read, and each of those outputs, or a file taken out of a CPA package), and any text file holding one: a TIN the vault keeps, written as nine digits or in the usual groups (3-2-4 with hyphens, spaces or dots; 2-7 with a hyphen or a space), or a number printed as an SSN or EIN is (3-2-4 or 2-7 digits joined by hyphens, not part of a longer number). Other numbers pass, so bank exports (routing and account numbers, long references) go in. It can't recognize an altered copy of a scan, or a TIN the vault doesn't keep written any other way, so never file a W-9 or a TIN worksheet yourself.
- Receipts come back out through books.get_receipt.