python - 遇到 : json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Question

我收到了 json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)当我尝试从我创建的 json 文件访问值时。我运行了下面的runfile，似乎有这个解码器问题，但是，当创建json文件时，我将加密的内容作为字符串添加到json文件的字典中。有人可以帮我找出问题所在吗？

错误是:

{
    "youtube": {
        "key": "D5IPLv06NGXut4kKdScNAP47AieP8wqeUINr6EFLXFs=",
        "content": "gAAAAABclST8_XmHrAAfEbgrX-r6wwrJf7IAtDoLSkahXAraPjvoXeLl3HLkuHbW0uj5XpR4_jmkgk0ICmT8ZKP267-nnjnCpw=="
    },
    "facebook": {
        "key": "YexP5dpgxwKhD8Flr6hbJhMiAB1nmzZXi2IMMO3agXg=",
        "content": "gAAAAABclST8zSRen_0sur79NQk9Pin16PZcg95kEHnFt5vjKENMPckpnK9JQctayouQ8tHHeRNu--s58Jj3IPsPbrLoeOwr-mwdU5KvvaXLY-g6bUwnIp4="
    },
    "instagram": {
        "key": "ew2bl0tKdlgwiWfhB0jjSrOZDb41F88HULCQ_21EDGU=",
        "content": "gAAAAABclST8FKcZqasiXfARRfbGPqb3pdDj4aKuxeJoRvgIPbVIOZEa5s34f0c_H3_itv5iG1O7u8vvlT8lAPTgAp3ez8OBh4T2OfBG-ObljYmIt7exi0Q="
    }
}
Traceback (most recent call last):
  File "C:\Users\YOURNAME\Desktop\randomprojects\content_key_writer.py", line 65, in <module>
    main()
  File "C:\Users\YOURNAME\Desktop\randomprojects\content_key_writer.py", line 60, in main
    data_content = json.load(data_file)
  File "C:\Users\YOURNAME\AppData\Local\Programs\Python\Python37\lib\json\__init__.py", line 296, in load
    parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
  File "C:\Users\YOURNAME\AppData\Local\Programs\Python\Python37\lib\json\__init__.py", line 348, in loads
    return _default_decoder.decode(s)
  File "C:\Users\YOURNAME\AppData\Local\Programs\Python\Python37\lib\json\decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "C:\Users\YOURNAME\AppData\Local\Programs\Python\Python37\lib\json\decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

原来的代码贴在这里，命名为runfile:

import sys
import os
from cryptography.fernet import Fernet
import json
import pathlib
from encipher_decipher import encrypt, decrypt, bytes_to_str, str_to_bytes 

def content_key_writer(path, filename, account, content):
    """Generate key corresponding to an account, save in json"""
    # make the path a Path object
    path = pathlib.Path(path)
    file_path = os.path.join(path, filename)

    # generate a key using Fernet
    key = Fernet.generate_key()
    # json doesn't support bytes, so convert to string
    key = bytes_to_str(key)

    # with file_path, see if the file exists
    if not os.path.exists(file_path):
        # build the dictionary to hold key and content
        data = {}
        data[account] = {}
        data[account]['key'] = key
        data[account]['content'] = encrypt(content, key)


        # if the file doesn't exist, build the new json file
        with open(file_path, 'w') as f:
            json.dump(data, f)
    else:
        # if the file does exist
        with open(file_path, 'r') as f:
            data = json.load(f)
            data[account] = {} # <--- add the account 
            data[account]['key'] = key
            data[account]['content'] = encrypt(content, key)

        os.remove(file_path) # <--- remove the file and rewrite it
        with open(file_path, 'w') as f:
            json.dump(data, f, indent=4)

def main():
    path = "C:/Users/YOURNAME/Desktop/randomprojects"
    name = 'content.json'
    account = 'youtube'
    content = 'youtubepassword'
    account2 = 'facebook'
    content2 = 'facebookpassword'
    account3 = 'instagram'
    content3 = 'instagrampassword'

    content_key_writer(path, name, account, content)
    content_key_writer(path, name, account2, content2)
    content_key_writer(path, name, account3, content3)
    new_path = os.path.join(pathlib.Path(path),name)
    with open(new_path) as data_file:
        data = data_file.read()
        print(data) 
        data_content = json.load(data_file)
    value = data_content['youtube']['content']
    print(value)

if __name__ == '__main__':
    main()

上面代码中引入的模块是encipher_decipher:

"""
Given an information, encrypt and decrypt using the given key
"""

from cryptography.fernet import Fernet
import os

def encrypt(information, key):
    """encrypt information and return as string"""
    f = Fernet(key)
    information_bytes = str_to_bytes(information) 
    encrypted_info = f.encrypt(information_bytes) #<--- returns bytes
    encrypted_info = bytes_to_str(encrypted_info) #<--- to save in json requires str not bytes
    return encrypted_info

def decrypt(information, key):
    """decrypt information and return as string"""
    f = Fernet(key)
    information_bytes = str_to_bytes(information)
    decrypted_info = f.decrypt(information_bytes) #<--- returns bytes
    decrypted_info = bytes_to_str(decrypted_info) #<--- converts to string
    return decrypted_info

def bytes_to_str(byte_stuff):
    """Convert bytes to string"""
    return byte_stuff.decode('utf-8')

def str_to_bytes(str_stuff):
    """Converts string to bytes"""
    return bytes(str_stuff, 'utf-8') # or str_stuff.encode('utf-8')

Answer 1

问题是这段代码:

with open(new_path) as data_file:
  data = data_file.read()
  print(data) 
  data_content = json.load(data_file)

您正在将文件内容读入 data ，打印出来，然后询问 json.load()再次从文件句柄中读取。然而此时，文件指针已经在文件的末尾，所以没有更多的数据，因此 json 错误: Expecting value
改为这样做:

with open(new_path) as data_file:
  data = data_file.read()
  print(data) 
  data_content = json.loads(data)

您已经将数据读入 data ，因此您可以将该字符串输入 json.loads()