json turns to a double quoted string - python django

Question

I have a rather weird question:

So, I have a simple dictionary in python, looking like so:

data={'Acoustics': {'Product Type': 'Acoustic Pod', 'Width [cm]': '1000', 'Noise Reduction Coefficient': '29 dB', 'Standards, Certification, and Documentation': 'PN EN-ISO 717-1:1999 ;  EN 13501 B, s1, d0', 'Material': 'MDF ;  Glass ;  Acoustic composite', 'Color': 'NCS ;  RAL', 'Installation Method': 'Own assembly ;  Installation by the manufacturer', 'Facing Material': 'MDF ;  Certified Paint', 'Type': 'Adjustable Ventilation ;  Motion Sensor ;  LED 6000K 2W ;  230V ;  RJ45 or USB Charger ;  Integrated seat and shelf'}}

and I try to save this via django onto my pgSQL database (with jsonb column), and I somehow end up with (notice the double quote at the start and end):

"{'Acoustics': {'Product Type': 'Acoustic Pod', 'Width [cm]': '1000', 'Noise Reduction Coefficient': '29 dB', 'Standards, Certification, and Documentation': 'PN EN-ISO 717-1:1999 ;  EN 13501 B, s1, d0', 'Material': 'MDF ;  Glass ;  Acoustic composite', 'Color': 'NCS ;  RAL', 'Installation Method': 'Own assembly ;  Installation by the manufacturer', 'Facing Material': 'MDF ;  Certified Paint', 'Type': 'Adjustable Ventilation ;  Motion Sensor ;  LED 6000K 2W ;  230V ;  RJ45 or USB Charger ;  Integrated seat and shelf'}}"

To add to my DB, I use django forms like so:

form_data={"cvar": data}
form = myform(form_data)
if form.is_valid():
    form.save()

So, now, I have two questions: [1] How do I avoid the above scenario? Why is it getting quoted ? I simply pass a form data to save and it somehow ends up as a string rather than json. [2] If I have such quoted json (which unfortunately I do now), how do I unquote and access this as a json (at the moment it is a damn string!).

Thank you.

Answer 1

It isn't easy to figure out without MCVE showing the relevant code .

It looks like you wrote to the database a dictionary converted to string and then converted to JSON, instead of converting the dictionary to json directly.

Like:

>>> import json
>>> a={'Acoustics': {'Product Type': 'Acoustic Pod', 'Width [cm]': '1000', 'Noise Reduction Coefficient': '29 dB', 'Standards, Certification, and Documentation': 'PN EN-ISO 717-1:1999 ;  EN 13501 B, s1, d0', 'Material': 'MDF ;  Glass ;  Acoustic composite', 'Color': 'NCS ;  RAL', 'Installation Method': 'Own assembly ;  Installation by the manufacturer', 'Facing Material': 'MDF ;  Certified Paint', 'Type': 'Adjustable Ventilation ;  Motion Sensor ;  LED 6000K 2W ;  230V ;  RJ45 or USB Charger ;  Integrated seat and shelf'}}

and then:

>>> print(json.dumps(str(a)))
"{'Acoustics': {'Product Type': 'Acoustic Pod', 'Width [cm]': '1000', 'Noise Reduction Coefficient': '29 dB', 'Standards, Certification, and Documentation': 'PN EN-ISO 717-1:1999 ;  EN 13501 B, s1, d0', 'Material': 'MDF ;  Glass ;  Acoustic composite', 'Color': 'NCS ;  RAL', 'Installation Method': 'Own assembly ;  Installation by the manufacturer', 'Facing Material': 'MDF ;  Certified Paint', 'Type': 'Adjustable Ventilation ;  Motion Sensor ;  LED 6000K 2W ;  230V ;  RJ45 or USB Charger ;  Integrated seat and shelf'}}"

instead of:

>>> print(json.dumps(a))
{"Acoustics": {"Product Type": "Acoustic Pod", "Width [cm]": "1000", "Noise Reduction Coefficient": "29 dB", "Standards, Certification, and Documentation": "PN EN-ISO 717-1:1999 ;  EN 13501 B, s1, d0", "Material": "MDF ;  Glass ;  Acoustic composite", "Color": "NCS ;  RAL", "Installation Method": "Own assembly ;  Installation by the manufacturer", "Facing Material": "MDF ;  Certified Paint", "Type": "Adjustable Ventilation ;  Motion Sensor ;  LED 6000K 2W ;  230V ;  RJ45 or USB Charger ;  Integrated seat and shelf"}}

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If you already have the python dictionary representation as a string from some external data source, then you can use ast.literal_eval() to turn it to a proper dict first :

>>> the_dict=ast.literal_eval(the_data)
>>> the_json=json.dumps(the_dict)

Or, preferably, change the data source (for example a web form) to use JSON format instead of Python dict text representation for exchanging data.