Base64 shenanigans in Python

TypeError: a bytes-like object is required, not 'str'

This error occurs when you try to base64 encode or decode a string instead of an appropriate bytes-like object. This is a common issue and originates from when Python changed some of its string mechanics from version 2 to 3. To solve this, make sure you are handling the casting correctly, summarized below.

Encoding a String using Base64 in Python

You can base64 encode a string in Python by first converting it into its appropriate bytes and then using the b64encode method:

import base64

# This is the string you want to encode to base64
my_string = 'Hello World'

# First, encode the string into its respective bytes using the encode method.
# This can be set as ascii, uti-8, utf-16, utf-32
my_bytes = my_string.encode('utf-8')

# Next, use the base64 encode method to encode the bytes to base64
base64_bytes = base64.b64encode(my_bytes)

# Finally, you can convert the bytes to a string again if needed:
base64_string = str(base64_bytes)

print(base64_string)

You can also take this a step further and eliminate the need to encode the string to bytes by prepending the string with a byte indicator like so:

my_bytes = b'Hello World'

base64_string = str(base64.b64encode(my_bytes))

print(base64_string)

Decoding a String using Base64 in Python

Decoding a base64 string works similar to encoding. Just be sure not to mix up strings with byte strings!

import base64

# This is the string you want to decode
my_string = 'SGVsbG8gV29ybGQ='

# First, transform the string into its respective bytes
my_bytes = my_string.encode('utf-8')

# Next, use the base64 decode method to decode the bytes to base64
base64_bytes = base64.b64decode(my_bytes)

# Finally, you can convert the bytes to a string again if needed:
decoded_string = str(base64_bytes)

print(decoded_string)