[fix] Fixed REST API can creates device configs inadvertently #699

[pandafy]

Fixes #699

[coveralls]

Coverage: 98.907% (+0.9%) from 98.035% when pulling e09895d on issues/699-device-config into 22590a4 on master.

[nemesifier]

this should compare to the default value of the Config.backend field, which if I remember correctly can be modified via OPENWISP_CONTROLLER_DEFAULT_BACKEND.

[nemesifier]

Can you get the default values from the serializer fields and compare each property to the corresponding serializer field default? Such a solution would be more robust to future changes, I doubt anyone changing the default values (if ever needed, but we never know) of the serializer or model will remember to change this.

[pandafy]

The ModelSerializer defers enforcing defaults to the model
encode/django-rest-framework#2683

[pandafy]

The Browsable API is not using the default values defined in serializer fields when rendering form for Device object that does not have a Config:

The context and config field values are set to null instead of {}. When form with such values is saved, then serializer parses the data to

{
    'backend': 'netjsonconfig.OpenWrt',
     'config': None,
     'context': None,
     'templates': []
}

Which is different from the default values defined for the field:

{
    'backend': 'netjsonconfig.OpenWrt',
     'config': {},
     'context': {},
     'templates': []
}

I have enquired about this on DRF's mailing list.

[nemesifier]

no problem let's use the model then