get oss policy for python3

oss_post_policy.py

import datetime
import time
import base64
import json
import hmac
from hashlib import sha1 as sha

expire_time = 30
upload_dir = settings.ALIYUN_OSS_DIRECTORY_PREFIX


def get_iso_8601(expire):
    gmt = datetime.datetime.fromtimestamp(expire).isoformat()
    gmt += 'Z'
    return gmt


def get_token():
    now = int(time.time())
    expire_syncpoint = now + expire_time
    expire = get_iso_8601(expire_syncpoint)

    policy_dict = {}
    policy_dict['expiration'] = expire
    condition_array = []
    array_item = []
    array_item.append('starts-with')
    array_item.append('$key')
    array_item.append(upload_dir)
    condition_array.append(array_item)
    policy_dict['conditions'] = condition_array
    policy = json.dumps(policy_dict).strip()
    policy_encode = base64.b64encode(policy.encode())
    h = hmac.new(settings.ACCESS_KEY_SECRET.encode(), policy_encode, sha)
    sign_result = base64.b64encode(h.digest()).strip()

    token_dict = {}
    token_dict['accessid'] = settings.ACCESS_KEY_ID
    token_dict['host'] = settings.ALIYUN_OSS_CDN_URL
    token_dict['policy'] = policy_encode.decode("utf-8")
    token_dict['signature'] = sign_result.decode("utf-8")
    token_dict['expire'] = expire_syncpoint
    token_dict['dir'] = upload_dir
    result = json.dumps(token_dict)
    return result