1.编码去'='

# -*- coding: utf-8 -*-
import base64
def safe_base64_encode(s):
    b64 = base64.b64encode(s)
    if b64[-1:] == b'=':
      while b64[-1:] == b'=':
          b64 = b64[:-1]
      return b64
    else:
      return b64  
# assert b'YWJjZA' == safe_base64_decode(b'abcd'), safe_base64_decode(b'abcd') 

2.解码去'='的base64

# -*- coding: utf-8 -*-
import base64
def safe_base64_decode(s):
    x = len(s)%4
    if x==0:
        return base64.b64decode(s)
    else:
        return base64.b64decode(s + b'='*(4-x))