python图片和字符串的转换

有个业务，需要将图片压缩转化为64位编码上传到服务端。

import json,requests,base64
#网上下载图片素材
r = requests.get("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1552573900887&di=4e80542ac9bbb801c7f1cf60fe355570&imgtype=0&src=http%3A%2F%2Fimg009.hc360.cn%2Fg1%2FM09%2F67%2F82%2FwKhQL1L26KyEFHl5AAAAAN7_Cqw821.jpg")
with open('beng.jpg','wb') as f:
    f.write(r.content)

# 图片的二进制字符串
with open('beng.jpg', 'rb') as f:
    content2 = f.read()
with open("beng2.jpg", 'wb') as f:
    f.write(content2)

#图片的64位字符串
with open('beng.jpg','rb') as f:
    content1 =  base64.b64encode(f.read())
with open('beng1.jpg','wb') as f:
    f.write(base64.b64decode(content1))

然后应用，先将客户端生成的64位字符保存为baseC.txt，再将服务端返回的64位字符串保存为baseS.txt。
1.先对2组64位字符长度进行比较
2.分别保存为图片

import json,base64

#获取客户端的64位字符串
with open('baseC.txt', 'rb') as f:
    byteC = f.read()
    # print(isinstance(byteC,bytes))

#获取服务端的64位字符串
with open('baseS.txt','r') as f:
    #获取服务端的图片编码
    strS = json.loads(f.read())['data']
    #去除b''，先转化为byte
    byte1 = str.encode(strS,"ASCII")
    #使用decode去除b''
    strS = bytes.decode(byte1,"utf-8")
    byteS = str.encode(strS, "ASCII")

with open("baseC.jpg","wb") as f:
    f.write(base64.b64decode(byteC))

with open("baseS.jpg","wb") as f:
    f.write(base64.b64decode(byteS))

经过比对，服务端保存的字符串存储图片失败，客户端保存图片无内容，因此先修复客户端，再进行比对