如何将 PDF 从 base64 字符串转换为文件？

Question

I have a PDF as a base64 string and I need to write it to file using Python. I tried this:

import base64

base64String = "data:application/pdf;base64,JVBERi0xLjQKJeHp69MKMSAwIG9iago8PC9Qcm9kdWNlciAoU2tpYS9..."

with open('temp.pdf', 'wb') as theFile:
  theFile.write(base64.b64decode(base64String))

But it didn't create a valid PDF file. What am I missing?

Answer 1

From my understanding base64decode only takes in a base64 string and looks like you have some headers on your string that are not encoded.

I would remove "data:application/pdf;base64,"

check out the doc here: https://docs.python.org/2/library/base64.html

When I've used it in the past, I have only used the encoded string.

Answer 2

Does writing it by using the codecs.decode function work? also as Mark stated, you can try to remove the data:application/pdf;base64, portion of the string as this section of the string is not to be decoded.:

import codecs
base64String = "JVBERi0xLjQKJeHp69MKMSAwIG9iago8PC9Qcm9kdWNlciAoU2tpYS9..."


with open("test.pdf", "wb") as f:
    f.write(codecs.decode(base64string, "base64"))

Answer 3

This is not just base64 encoded data, but data-uri encoded:

https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URIs

There is another post on stack overflow asking how to parse such strings in Python:

How to parse data-uri in python?

The gist of it is to remove the header (everything up to and including the first comma):

theFile.write(base64.b64decode(base64String.split(",")[1:2]))

NOTE: I use [1:2] instead of [1] because it won't throw an exception if there is only 1 element in the list because nothing follows the comma (empty data).

Answer 4

Extending @Jebby 's answer using Base64 (had the same issue as @SmartManoj )

import base64
base64String = "JVBERi0xLjQKJeHp69MKMSAwIG9iago8PC9Qcm9kdWNlciAoU2tpYS9..."


with open("test.pdf", "wb") as f:
    f.write(base64.b64decode(base64string))