在 Python 中读取 JSON 格式的字符串

Question

I have a simple Websockets server in python, it receives messages from Android app clients, I tried to make the message payload from the client in JSON but I felt. It is only working when it is in String. One solution I found is to keep the message string but with JSON format:

try {
    json.put("name", "Jack");
    json.put("age", "24");
    message = json.toString(2);
} catch (JSONException e) {
    e.printStackTrace();
}

webSocket.send(message);

Inspired by the Javascript JSON.stringify(message)

I printed the message on the server and it seems to be formatted

My question is how can I reverse back it into JSON on the server when it received?

I tried this way in Python:

def on_message(self,message):
    data = json.loads(message)
    self.write_message(data['name'])

but I got this error:

ERROR:tornado.application:Uncaught exception in /
Traceback (most recent call last):
  File "/usr/local/lib/python3.4/dist-packages/tornado/websocket.py", line 494, in _run_callback
    result = callback(*args, **kwargs)
  File "index.py", line 24, in on_message
    data = json.loads(message)
  File "/usr/lib/python3.4/json/__init__.py", line 318, in loads
    return _default_decoder.decode(s)
  File "/usr/lib/python3.4/json/decoder.py", line 343, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib/python3.4/json/decoder.py", line 361, in raw_decode
    raise ValueError(errmsg("Expecting value", s, err.value)) from None
ValueError: Expecting value: line 1 column 1 (char 0)

Answer 1

You should use the json Python package. To have a JSON, you could simply do import json and json.dumps(message) .

Answer 2

Will something like this work for you?

import json

# assume this is the JSON you receive
text = json.dumps(dict(name='Jack', age='24'))

# show the text to be converted
print(text)
# outputs: {"name": "Jack", "age": "24"}

# load a string and convert to Python object
# see `json` module more for details
obj = json.loads(text) 

Answer 3

Use a Json package in python

import json
data = json.loads(your_var)

In data variable you get a json format data

hope this will help you

Answer 4

I tried this way and it worked for me, I converted the message into a dictionary using ast and then used the new message as I wanted:

    formattedMessage = ast.literal_eval(format(message))
    self.write_message(formattedMessage["name"])