pre_upload.py

from boto3 import Session
import string
import random

ACCESS_KEY = "your access key"
SECRET_KEY = "your_secret_key"
REGION_NAME = "your bucket's region name"
BUCKET_NAME = "your bucket name"

ses = Session(aws_access_key_id=ACCESS_KEY,
              aws_secret_access_key=SECRET_KEY,
              region_name=REGION_NAME)

key = ''.join(random.choice(string.ascii_uppercase + string.ascii_lowercase + string.digits) for _ in range(10))
s3 = ses.client('s3')
url = s3.generate_presigned_post(Bucket=BUCKET_NAME, Key=key, ExpiresIn=3600)