Token expire before file was uploaded - python-2.7

Question

I'm using requests session with oauth2 authentication.
Everything works perfectly when I upload small files, but for 4GB file I get token expired error, it looks like the file was uploaded but at the closing session part token was once more validated.
Is there any chance to handle this situation?
Upload large file with token refreshed before the session was closed or something?
a sample of the code is below, Thank You very much for any help. Cheers!
import requests
from io import StringIO
from requests_toolbelt.multipart.encoder import MultipartEncoder
TOKEN_PAYLOAD = {
'grant_type': 'password',
'client_id': '###',
'client_secret': '###',
'username': '###',
'password': '####'
}
def get_token():
response = requests.post(
'https://oauth/token',
params=TOKEN_PAYLOAD)
response_data = response.json()
token = response_data.get('access_token')
return token
# Create test file
MB = 1024 ** 2
GB = MB * 1024
encoded_string = 'x' * 4 * GB
file_test = StringIO()
file_test.write(encoded_string)
# Get token
token = get_token()
# Create form
multipart_data = MultipartEncoder(
fields={
'--': ('4GB_test.txt', file_test, 'text/plain'),
'id': '2217',
'fileFieldDefId': '4258',
}
)
# Create headers
headers = {
"Authorization": "Bearer {}".format(token),
'Content-Type': multipart_data.content_type
}
session = requests.Session()
response = session.post(
'https://oauth2/rest/external/item/multipartUpdate/byId',
headers=headers,
data=multipart_data,
)
print(response)
# <Response [401]>
print(response.content)
# b'{"error":"invalid_token","error_description":"Access token expired: 0f7f6bd9-4e21-407f-4a78347711a9"}'
# response.close() ? with refreshed token
# session.close() ? with refreshed token

Answer 1

If you want to have valid access tokens for more time you can also request for refresh tokens and use them to generate new access tokens whenever the old one expires. Generally access tokens are valid for 1 hour, you can maintain a timer and generate a new access token every time your timer reaches 60 minutes. That way you can have a valid access token for longer sessions.
You have to use grant_type=refresh_token https://www.rfc-editor.org/rfc/rfc6749#section-6