Serialize in JSON a base64 encoded data

Question

I\'m writing a script to automate data generation for a demo and I need to serialize in a JSON some data. Part of this data is an image, so I encoded it in base64, but when

Answer 1

You must be careful about the datatypes.

If you read a binary image, you get bytes. If you encode these bytes in base64, you get ... bytes again! (see documentation on b64encode)

json can't handle raw bytes, that's why you get the error.

I have just written some example, with comments, I hope it helps:

from base64 import b64encode
from json import dumps

ENCODING = 'utf-8'
IMAGE_NAME = 'spam.jpg'
JSON_NAME = 'output.json'

# first: reading the binary stuff
# note the 'rb' flag
# result: bytes
with open(IMAGE_NAME, 'rb') as open_file:
    byte_content = open_file.read()

# second: base64 encode read data
# result: bytes (again)
base64_bytes = b64encode(byte_content)

# third: decode these bytes to text
# result: string (in utf-8)
base64_string = base64_bytes.decode(ENCODING)

# optional: doing stuff with the data
# result here: some dict
raw_data = {IMAGE_NAME: base64_string}

# now: encoding the data to json
# result: string
json_data = dumps(raw_data, indent=2)

# finally: writing the json string to disk
# note the 'w' flag, no 'b' needed as we deal with text here
with open(JSON_NAME, 'w') as another_open_file:
    another_open_file.write(json_data)