INVALID_REQUEST_PARAMETER - filename not found in Content-Disposition header of multipart form - docusignapi

Question

I am attempting to add a document by multipart form to an existing draft envelope via the Docusign REST API endpoint: /envelopes/[envelopeId]/documents/[documentId]
The error message I get is:
The request contained at least one invalid parameter. A filename was not
found in the Content-Disposition header ('filename="filename.ext"
As you can see, there is a filename parameter in the Content-Disposition value. I've tried multiple different edits and adjustments of the Content-Disposition header, but each has failed. Here is what appears to be the correct format that throws the error.
Headers:
Authorization "Bearer [token]"
Accept "application/json"
Content-Type "multipart/form-data; boundary=AAAAAA"
--AAAAAA
Content-Disposition: form-data
Content-Type: application/json
{"fileExtension":"pdf","name":"test file name.pdf","documentId":1,"order":1}
--AAAAAA
Content-Disposition: file; filename="test file name.pdf"; documentId=1
Content-Type: application/pdf
[binary output]
--AAAAAA--
Anyone from Docusign or in general able to see what's wrong or give me a hand? Thanks.

Answer 1

multipart/form-data will not work for the updateEnvelopeDocument api
Instead specify the Content-Type and content-disposition in the Headers. Request body should only contain the file stream.
put /envelopes/[envelopeId]/documents/[documentId]
[Headers]
Content-Type: application/pdf
content-disposition: file; filename="test file name.pdf"; fileExtension=pdf; documentId=1
[Body]
[binary output]

Answer 2

The other option is to use the updateListEnvelopeDocuments api which supports multipart/form-data. You can also choose to update multiple documents in a single api call using this api.
PUT /v2/accounts/{accountId}/envelopes/{envelopeId}/documents
Headers:
Authorization "Bearer [token]"
Accept "application/json"
Content-Type "multipart/form-data; boundary=AAAAAA"
--AAAAAA
Content-Type: application/json
Content-Disposition: form-data
{
"documents": [
{
"documentId": 1,
"fileExtension": "pdf",
"name": "test file name.pdf"
}
]
}
--AAAAAA
Content-Type: application/pdf
Content-Disposition: file; filename="test file name.pdf"; fileExtension=pdf; documentId=1
Content-Transfer-Encoding: stream
[Binary output]
--AAAAAA--