python - 如何在 Python 中使用 Base64 解码此字符串时避免 "Incorrect padding"错误

Question

我有以下字符串，我想使用 Python 对其进行 Base64 解码。

eyJqa3UiOiJodHRwczovL2U5N2I4YTlkNjcyZTRjZTQ4NDVlYzY5NDdjZDY2ZWY2LXNiLmJhYXMubmludGVuZG8uY29tLzEuMC4wL2NlcnRpZmljYXRlcyIsImtpZCI6ImZlOWRiYmZmLTQ3MGItNDZjOC04YmFmLTFiNzY5OGRlZTViZSIsImFsZyI6IlJTMjU2In0.eyJpc3MiOiJodHRwczovL2U5N2I4YTlkNjcyZTRjZTQ4NDVlYzY5NDdjZDY2ZWY2LXNiLmJhYXMubmludGVuZG8uY29tIiwiZXhwIjoxNTQ1MTg1NDk2LCJ0eXAiOiJpZF90b2tlbiIsImF1ZCI6IjhkOTc1NTllNjNlY2NkNTYiLCJiczpkaWQiOiI2NjJhZTQwOWYwNTQyYTBjIiwic3ViIjoiOTNkYmYwNDdiYTI3NzQ5NSIsImp0aSI6IjY1NDg4ZjJmLTI1NzAtNDBkYy04ODQ3LTMzODNlZWIxMGJiYiIsIm5pbnRlbmRvIjp7ImFpIjoiMDEwMGY4MDAwMDQ5MjAwMCIsImF2IjoiMDAwMCIsImVkaSI6ImJjNTdiYmM3MTZlMDA1MGFmOWRhN2NkYTIzMWRjZDgyIiwiYXQiOjE1NDUxNzQ2OTZ9LCJpYXQiOjE1NDUxNzQ2OTZ9.ZMUIt3wYrbfhXnnDh4WraGlKrZy0YuL5prluY70sU_-0W5XvWIB-xmTrLz7LJWHEGwTskcWf81_HBq_mSb75rMfTAEBwBmOJ4ITmhdnXksz8w7EDOWuPPSEft5XLMNOMD16ztEOYe5ddU_iqNEbT56L7fcAJEXv0FWy6H_OutxOglYpDaNkcj6CWJ7dpA0JbqerR9dEszaLwyn1ZBDPVD0YeAIm5bEr61imeedzMb0amxlTl4R87mqK6epsFUnRy6p6Klr27_DlTLQ-gej09W7NeNzONCj4thHgCr9szAiaN28krfTc2fobz3qFCoC_eQghiIIZBe_-Lksng3Eg6tw

当我转到这个 https://www.base64decode.org/并将其放入，我可以看到解码字符串的第一部分是可读的纯文本:

但是，当我尝试使用 Python 对其进行解码时，它失败了:

>>> import base64
>>> x = "eyJ......"
>>> base64.b64decode(x)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/base64.py", line 76, in b64decode
    raise TypeError(msg)
TypeError: Incorrect padding

我试过了 this remedy .但它并没有改变由此产生的错误。我该如何解决这个问题？为什么它不像那个网站那样解码？

Answer 1

嗯，看起来消息被 . 分成了三部分。前两部分是 base64 编码的，而最后一部分不是:

import base64

res = "eyJqa3UiOiJodHRwczovL2U5N2I4YTlkNjcyZTRjZTQ4NDVlYzY5NDdjZDY2ZWY2LXNiLmJhYXMubmludGVuZG8uY29tLzEuMC4wL2NlcnRpZmljYXRlcyIsImtpZCI6ImZlOWRiYmZmLTQ3MGItNDZjOC04YmFmLTFiNzY5OGRlZTViZSIsImFsZyI6IlJTMjU2In0.eyJpc3MiOiJodHRwczovL2U5N2I4YTlkNjcyZTRjZTQ4NDVlYzY5NDdjZDY2ZWY2LXNiLmJhYXMubmludGVuZG8uY29tIiwiZXhwIjoxNTQ1MTg1NDk2LCJ0eXAiOiJpZF90b2tlbiIsImF1ZCI6IjhkOTc1NTllNjNlY2NkNTYiLCJiczpkaWQiOiI2NjJhZTQwOWYwNTQyYTBjIiwic3ViIjoiOTNkYmYwNDdiYTI3NzQ5NSIsImp0aSI6IjY1NDg4ZjJmLTI1NzAtNDBkYy04ODQ3LTMzODNlZWIxMGJiYiIsIm5pbnRlbmRvIjp7ImFpIjoiMDEwMGY4MDAwMDQ5MjAwMCIsImF2IjoiMDAwMCIsImVkaSI6ImJjNTdiYmM3MTZlMDA1MGFmOWRhN2NkYTIzMWRjZDgyIiwiYXQiOjE1NDUxNzQ2OTZ9LCJpYXQiOjE1NDUxNzQ2OTZ9.ZMUIt3wYrbfhXnnDh4WraGlKrZy0YuL5prluY70sU_-0W5XvWIB-xmTrLz7LJWHEGwTskcWf81_HBq_mSb75rMfTAEBwBmOJ4ITmhdnXksz8w7EDOWuPPSEft5XLMNOMD16ztEOYe5ddU_iqNEbT56L7fcAJEXv0FWy6H_OutxOglYpDaNkcj6CWJ7dpA0JbqerR9dEszaLwyn1ZBDPVD0YeAIm5bEr61imeedzMb0amxlTl4R87mqK6epsFUnRy6p6Klr27_DlTLQ-gej09W7NeNzONCj4thHgCr9szAiaN28krfTc2fobz3qFCoC_eQghiIIZBe_-Lksng3Eg6tw"

for i in res.split("."):
    print(base64.b64decode(i + '=' * (-len(i) % 4)))

我猜最后一个是签名，用来验证前两部分。你从cookie中得到这个字符串吗？还是来自提交的表单？

编辑

所以对于任何看到这个答案的人来说，给定的字符串是一个 JWT字符串。