[eastbound]

So there are 7 base64 encodings, one with “+ / =“, one with “- _ =“, one with “+,” and no “=“… https://en.wikipedia.org/wiki/Base64#Variants_summary_table

[rendaw]

And decoders typically aren't interoperable, requiring you to use the specific decoder for that combination.

[layer8]

Which is silly, because there’s no good reason to, except for strict validation.

[BiteCode_dev]

TIL.

And Python uses RFC 4648

[masklinn]

Python might say that, but as often it’s not really true: it really mostly works off of 2045

- the “default” encoder (“b64encode”) will pad the output

- although it will not linebreak (“encodebytes”) does that)

- the default decoder will error if the input is not padded

- the default decoder will ignore all non-encoding characters by default

Also both b64encode and encodebytes actually use binascii.b2a_base64, which claims conformance to RFC 3548, which attempts to unify 1421 and 2045. Except RFC 3548 requires rejecting non-encoding data, whereas (again) Python accepts an ignores it by default, in 2045 fashion.