JSONField: which app to choose ?

[Michael Palumbo]

Hi,

I have found several implementations of a Django JSON Field.

Have you ever tried one ? Which one do you recommend ?

Thanks.

https://github.com/bradjasper/django-jsonfield  

https://github.com/derek-schaefer/django-json-field  

https://bitbucket.org/schinckel/django-jsonfield/overview  

https://github.com/django-extensions/django-extensions/blob/master/django_extensions/db/fields/json.py   

http://djangosnippets.org/snippets/1478/  

http://djangosnippets.org/snippets/377/  

[Reinout van Rees]

On 09-07-12 20:52, Michael Palumbo wrote:
> Hi,
>
> I have found several implementations of a Django JSON Field.
> Have you ever tried one ? Which one do you recommend ?

I'm using the 'django-jsonfield' on pypi:
http://pypi.python.org/pypi/django-jsonfield/

It is https://bitbucket.org/schinckel/django-jsonfield/ on bitbucket.
I looked at it with a colleague and it seemed to have a bit more
validation than some others. Little things.


Reinout

--
Reinout van Rees http://reinout.vanrees.org/
rei...@vanrees.org http://www.nelen-schuurmans.nl/
"If you're not sure what to do, make something. -- Paul Graham"

[Michael Palumbo]

Can you get it work in the admin ?

I don't understand why I get a ValidationError  "[u"'' is not a valid JSON string."] as soon as I try to reach the Add admin page of my Model...

import jsonfield

class Mapping(models.Model):

    data_map4 = jsonfield.JSONField()

-----

class MappingAdmin(admin.ModelAdmin):

    fields = ['data_map4']

    list_display = ('data_map4',)

Thanks.

[Matt Schinckel]

Hi Michael.

It should 'just work' in the admin: I'm using it fairly extensively, and most of our access is through the admin (or a JSON api).

If we can get a minimal failing test, then I'll make sure it gets fixed.

(And thanks, Reinout, for the referral/comment)

Matt.

[Matt Schinckel]

Michael,

I've been able to reproduce it: I'm not quite sure of the best way to deal with it.

One solution is to set either null=True, or blank=True on the field, or set a default.

The trick is, an empty string isn't valid JSON. I guess I've always been using a default (usually of {} or [], depending upon context).

Happy for you to suggest improvements, though.

I believe it's actually related to https://bitbucket.org/schinckel/django-jsonfield/issue/13/integrityerrors-when-using-empty-string

Matt.

[Michael Palumbo]

Hi Matt,

Correct, using either null=True or blank=True on the field works.

However, I don't get it since I didn't click on "save", I just wanted to display the add page containing it. Why does it attempt to validate the field at this time and not wait for the form to be sent ? Maybe this is how Django works ?

Whatever, I think you can set a default value in the JSONField to avoid the error, what do you think ? I think it's handy.

improvement:

    def __init__(self, *args, **kwargs):

        kwargs['default'] = kwargs.get('default', '{}')

        super(JSONField, self).__init__(*args, **kwargs)

It works for me.

Another point: it does not like "extra" comma right ?

{

  "nodes": { "title": "title", }

}

But I guess this is wanted because JSON does not allow it ?

Michael