[Python] Upload a file to Salesforce using multipart-form

I am trying to upload a text file (also tried PDF, etc) to Salesforce. Text file contains 'hello world'.

Here is the code I am using

def putFile(sf, libname, filen):
file_name=os.path.basename(filen)
libId=libraryExists(sf, libname)
contentDocumentId = getContentDocumentId(sf, libname, file_name)
if not libId:
print(f"Provided library '{libname}' does not exists")
return

with open(filen, "rb") as f:
bodyEncoded = base64.b64encode(f.read())

boundary = '----------------------------741e90d31eff'
headers = {
'Content-Type' : 'multipart/form-data; boundary=' + boundary
}

nonBinaryPart = '--'+boundary+'\nContent-Disposition: form-data; name="entity_content";\n'
nonBinaryPart += 'Content-Type: application/json;\r\n\r\n'
nonBinaryPart += json.dumps({
"ContentDocumentId" : contentDocumentId,
"ReasonForChange" : "Large file upload",
"PathOnClient" : file_name
})
nonBinaryPart += '\r\n\r\n'

header = '--'+boundary+'\nContent-Disposition: form-data; name="VersionData"; filename="'+file_name+'";\nContent-Type: application/octet-stream\r\n\r\n'
footer = '--'+boundary+'--'
headerEncoded = header
last4Bytes = bodyEncoded[len(bodyEncoded)-4:len(bodyEncoded)]
print(type(last4Bytes))
print(last4Bytes)
if last4Bytes.endswith(b'=='):
last4Bytes = last4Bytes[0:2] + b'0K'
bodyEncoded = bodyEncoded[0:len(bodyEncoded)-4] + last4Bytes
footerEncoded = footer
reqBody = headerEncoded+str(bodyEncoded)+footerEncoded
elif last4Bytes.endswith(b'='):
print('Ends with =')
last4Bytes = last4Bytes[0:3] + b'N'
bodyEncoded = bodyEncoded[0:len(bodyEncoded)-4] + last4Bytes
footer = '\n' + footer;
footerEncoded = footer
reqBody = headerEncoded+str(bodyEncoded)+footerEncoded
else:
footer = '\r\n' + footer
footerEncoded = footer
reqBody = headerEncoded+str(bodyEncoded)+footerEncoded

reqBody = nonBinaryPart + reqBody

print('==================================================')
print(reqBody)
print('==================================================')

res = sf.contentVersion.create(reqBody, headers)

print(res)

print('Now downloading it...')
os.system('rm -f ' + filen + '_downloaded')
getFile(sf, contentDocumentId, filen + '_downloaded', './' )
print('Downloaded.')


os.system('md5sum ' + filen)
os.system('md5sum ' + filen + '_downloaded')


This results in following request body which seems is according to Salesforce guidelines: https://developer.salesforce.com/do.../api_rest/dome_sobject_insert_update_blob.htm

Headers:

Content-Type: multipart/form-data; boundary="----------------------------741e90d31eff" Accept: application/json

Request body:

------------------------------741e90d31eff Content-Disposition: form-data; name="entity_content"; Content-Type: application/json;

{"ContentDocumentId": "0699E000000lKbLQAU", "ReasonForChange": "Large file upload", "PathOnClient": "hello_world.txt"}

------------------------------741e90d31eff Content-Disposition: form-data; name="VersionData"; filename="hello_world.txt"; Content-Type: application/octet-stream

b'aGVsbG8gd29ybGQK' ------------------------------741e90d31eff--

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