python で画像を base64 エンコード

python で画像を base64 エンコードする方法のメモ。

プログラム

import sys
import io
import base64
import json


def read_image_file(image_file):
    with open(image_file, 'rb') as inst:
        image = inst.read()
        return image

    return None


def main():
    for i in range(1, len(sys.argv)):
        image_file = sys.argv[i]
        image = read_image_file(image_file)
        image_bytes = io.BytesIO(image).read()
        image_base64 = base64.b64encode(image_bytes).decode('utf-8')
        obj = {
            'id': i,
            'image_base64': image_base64,
        }
        print(json.dumps(obj, ensure_ascii=False))

    return 0

if __name__ == '__main__':
    res = main()
    exit(res)

実行結果

$ python image_base64.py img1.jpg img2.jpg

{"id": 1, "file_name": "img1.jpg", "image_base64": "/9j/4AA..."}
{"id": 2, "file_name": "img2.jpg", "image_base64": "/9j/4AA..."}