TypeError: Object of type mappingproxy is not JSON serializable

I am having an issue when trying to convert a class object to JSON format. Actually, I have an ECG class object and my expectation is to convert that object to a string in JSON format.

Ex: { “Source”: “MIT”, “FileName”: “100”, “Channel”: 2, “Record”: 11520000, “Time”: 1800, “SampleRate”: 500 }

ECGModel.py

class ECG(object):
@classmethod
def __init__(self, source, fileName, channel, record, time, sampleRate, ecg):
    self.Source = source
    self.FileName = fileName
    self.Channel = channel
    self.Record = record
    self.Time = time
    self.SampleRate = sampleRate
    self.ECG = ecg

# getting the values
@property
def value(self):
    print('Getting value')
    return self.Source, self.FileName, self.Channel, self.Record, self.Time, self.SampleRate, self.ECG

# setting the values
@value.setter
def value(self, source, fileName, channel, record, time, sampleRate, ecg):
    print('Setting value to ' + source)
    self.Source = source
    self.FileName = fileName
    self.Channel = channel
    self.Record = record
    self.Time = time
    self.SampleRate = sampleRate
    self.ECG = ecg

# deleting the values
@value.deleter
def value(self):
    print('Deleting value')
    del self.Source, self.Source, self.FileName, self.Channel, self.Record, self.Time, self.SampleRate, self.ECG

Main.py

import streamlit as st
import Processor as processor
import json

ecgProperty = processor.GetSourceProperty(r"C:Users100.dat")

st.write(type(ecgProperty))
st.write(ecgProperty)
jsonECGPropertyStr = json.dumps(ecgProperty.__dict__)
st.write(jsonECGPropertyStr)

Processor.py

import streamlit as st
import Controllers.ECGModel as ecgModel

def GetSourceProperty(filePath):
    ecg = ecgModel.ECG
    ecg.Source = "MIT"
    ecg.FileName = "100"
    ecg.Channel = 2
    ecg.Record = 11520000
    ecg.Time = 1800
    ecg.SampleRate = 500
    return ecg

Log:

<class 'type'>
<class 'Controllers.ECGModel.ECG'>
File "C:UsersxxxAppDataLocalProgramsPythonPython39libsite-packagesstreamlitscript_runner.py", line 354, in _run_script
    exec(code, module.__dict__)
File "D:SourceCodeBIS2019_MasterThesisECG_EvaluationMain.py", line 27, in <module>
    jsonECGPropertyStr = json.dumps(ecgProperty.__dict__)
File "C:UsersxxxAppDataLocalProgramsPythonPython39libjson__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
File "C:UsersxxxAppDataLocalProgramsPythonPython39libjsonencoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
File "C:UsersxxxAppDataLocalProgramsPythonPython39libjsonencoder.py", line 257, in iterencode
    return _iterencode(o, 0)
File "C:UsersxxxAppDataLocalProgramsPythonPython39libjsonencoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type mappingproxy is not JSON serializable

Answer

I tried to guess what you are trying to achieve. See if the following codes work for you

ECGModel.py

class ECG:
    def __init__(self, source, file_name, channel, record, time, sample_rate):
        self.source = source
        self.file_name = file_name
        self.channel = channel
        self.record = record
        self.time = time
        self.sample_rate = sample_rate

Processor.py

from ECGModel import ECG


def GetSourceProperty():
    return ECG(source="MIT", file_name="100", channel=2, record=11520000, time=1800, sample_rate=500)

Main.py: You may replace print with your st.write

import Processor
import json

ecg = Processor.GetSourceProperty()

print(type(ecg))
print(ecg)
print(json.dumps(ecg.__dict__))

Output

<class 'ECGModel.ECG'>
<ECGModel.ECG object at 0x000002ED4E82B670>
{"source": "MIT", "file_name": "100", "channel": 2, "record": 11520000, "time": 1800, "sample_rate": 500}