I am using python 3 & I have this code, trying to get base64 out of stream and returnn as json - but not working.

       stream = BytesIO()
       img.save(stream,format='png')
       return base64.b64encode(stream.getvalue())

in my view, I have:

hm =mymap()
    strHM = hm.generate(data)
return HttpResponse(json.dumps({"img": strHM}),content_type="application/json"  )

getting error is not JSON serializable. base64.b64encode(stream.getvalue()) seems giving bytes

In Python 3.x, base64.b64encode accepts a bytes object and returns a bytes object.

>>> base64.b64encode(b'a')
b'YQ=='
>>> base64.b64encode(b'a').decode()
'YQ=='

You need to convert it to str object, using bytes.decode:

return base64.b64encode(stream.getvalue()).decode()