Stephane,
I am not sure I understand uploading a document and leading with the metadata. The URL mentioned is not something I have tried. The resource I use to upload documents directly to a file cabinet is:
/DocuWare/Platform/FileCabinets/{cab guid}/Documents
I POST to that resource including a request header "Content-Type" with the MIME type of the document. The POST data then is simply a binary stream of the document's file contents, as that handles text or binary data.
After the POST, the returned XML contains the new document ID. I then use that document ID to post the index data via a routine we have for that which uses resource:
/DocuWare/Platform/FileCabinets/{cab guid}/Documents/{doc guid}/Fields
and POSTs XML that looks like something like this:
http://dev.docuware.com/schema/public/services" xmlns="">http://dev.docuware.com/schema/public/services/platform">
teststring
2018-07-03
2018-07-03T19:57:26Z
This has been working fine for us (on-premise 6.11) since September 2017.
(Sorry, I could never get JSON to work, so stuck with XML in all of my REST API calls...)
Thanks,
Joe Kaufman