Serializer fields for dictionaries and lists

[thedrow]

I don't see an option in the API to serialize dictionaries or lists although they are representable by non-model objects.
I also don't see a way to implement a custom field serializer through the current API.
It should be in the core anyway in my opinion.

[boxy-robot]

I'm stumbling through this as well. How would I create a field that just holds a list of strings? I have a m2m relationship in my models, but I just want to expose a list of strings through the API to make things simpler for my client app.

[kurtismullins]

+1

Django Models is not my use case. I am using Django-Rest-Framework to act as an API Endpoint for a lot of data stored in a NoSQL DBMS. This would make development significantly easier and less "hackish".

[timc3]

We are also using it for non-django data.

[dulacp]

I think that this SerializerMethodField can solve your issue @thedrow.

[donspaulding]

Can I ask what the ideal API for this would be? As @dulaccc mentioned, the SerializerMethodField can already return arbitrary python objects. What are the problems with that approach that you might expect this issue to address?

[rouge8]

As @dulaccc mentioned, the SerializerMethodField can already return arbitrary python objects. What are the problems with that approach that you might expect this issue to address?

SerializerMethodField is read-only, so I imagine they're looking for a read-write field.

[tomchristie]

Wrt to API I'd suggest something like ListField(contains=IntegerField). 'contains' could be optional.

On 6 Sep 2013, at 18:35, Don Spaulding notifications@github.com wrote:

Can I ask what the ideal API for this would be? As @dulaccc mentioned, the SerializerMethodField can already return arbitrary python objects. What are the problems with that approach that you might expect this issue to address?

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Reply to this email directly or view it on GitHub.

[gkappel]

I have been handling lists/arrays as follows which seems to work ok

class PGArrayField(serializers.WritableField):
    def to_native(self, obj):
        return json.dumps(obj)
    def from_native(self, obj):
        return json.loads(obj)

class PGHstoreField(serializers.WritableField):
    def to_native(self, obj):
        return json.dumps(obj)
    def from_native(self, obj):
        return json.loads(obj)

class SomeModel(models.model):
    attributes = DictionaryField(blank=True)
    aliases = ArrayField(dbtype="text",blank=True)

class SomeModelSerializer(serializers.ModelSerializer):
    attributes = PGHstoreField(required=False)
    aliases = PGArrayField(required=False)

    class Meta:
        model = SomeModel
        fields = ('id', 'attributes',  'aliases',)

[estebistec]

@gkappel how/where are you DictionaryField & ArrayField defined?

[gkappel]

from djorm_hstore.fields import DictionaryField
from djorm_pgarray.fields import ArrayField

See
https://github.com/niwibe/djorm-ext-hstore
https://github.com/niwibe/djorm-ext-pgarray

[tomchristie]

@estebistec: You may already have figured this, but note that those are model fields, not serializer fields.

[estebistec]

@tomchristie Doh! No I missed that detail. Thanks.

[estebistec]

BTW, long-term, my goal would be to generate serializers from schematics models to provide the convenience of model serializers but the flexibility needed for non-RDBMS data sources. I don't expect that to land here, it'll be a separate github project. But container types here could/would support it.

https://github.com/j2labs/schematics

[estebistec]

I'm thinking of something as simple as this for this issue: https://gist.github.com/estebistec/7775918 Is that more or less what others had in mind?

[tomchristie]

I'm thinking of something as simple as this for this issue: https://gist.github.com/estebistec/7775918 Is that more or less what others had in mind?

That's the idea, yup

[estebistec]

Actually, it appears BaseSerializer changes the signature of from_native to include a files parameter. So I'll have to do some finagling there before I submit a pull request.

[estebistec]

Created pull #1285 to implement this.

[tomchristie]

Closing pending update on third party package from @estebistec.