Base64 Encoding in Python 3

Published 2018-05-16 on Matthew's Blog

Recently I’ve been working on a backup script to backup a folder to a Backblaze B2 bucket. If only I had known I was about to spend an hour working on four silly lines of python code…

Backblaze’s documentation has absolutely no mention that this only works with Python 2. I’m not the only one. Pronoy had this exact issue with a Google API. Again, no mention it only works in Python 2. In fact, the moment I stumbled across Pronoy’s post is the same moment I stopped ripping my hair out.

Let’s get into the code. According to Backblaze’s API docs, they require the Account ID and Key to be base64 encoded in the following format: 'accoundId:accountKey'. Seems easy enough.

Try this in a Python 2 shell:

base64.b64encode('A string')

You get an output like:


Try running the same thing in a Python 3 shell and you see something closer to this:

  File "<stdin>", line 1, in <module>
  File "/usr/local/Cellar/python/3.6.5/Frameworks/Python.framework/ Versions/3.6/lib/python3.6/", line 58, in b64encode 
    encoded = binascii.b2a_base64(s, newline=False)
TypeError: a bytes-like object is required, not 'str'

The solution? There’s a few. Pronoy’s works: which is to encode the string in UTF-8. Then, once it’s base64 encoded, you decode that as ASCII.

This works:

base64.b64encode('A string'.encode('UTF-8')).decode('ascii')

After doing some more scouring, I found this Stackoverflow thread.

# The following works, too, and looks a little neater.
base64.b64encode(bytes('A string', 'utf-8')).decode('ascii')

Here’s another Stackoverflow thread explaining why.

Have a comment on one of my posts? Start a discussion in my public inbox by sending an email to ~mjorgensen/ [mailing list etiquette]

Articles from blogs I follow around the net

Shell access for CI

Have you ever found yourself staring at a failed CI build, wondering desperately what happened? Or, have you ever needed a fresh machine on-demand to test out an idea in? Have you been working on Linux, but need to test something on OpenBSD? Starting this we…

via Drew DeVault's Blog August 19, 2019

Living the Slaughterhouse

via gokigen August 14, 2019

Google Alternatives for More Privacy and Less Monopoly

I hope I don’t have to explain why Google is bad, but just to give a few reasons to switch to alternatives: You’ll probably get better privacy because those alternatives collect less data about you, your data won’t get sold to advertisers or government or…

via Posts on jlelse's Blog August 7, 2019

Generated by openring

Recent Posts

Hi there!

I'm a systems administrator, front-end and back-end developer, and an IT guru in Minneapolis, MN. It’s nice to meet you.