Using marshmallow schema to restrict update fields.

[marshmallow-code]

Using marshmallow schema to restrict update fields.

[sloria]

Here are a couple different approaches you could take:

Option 1: Field parameter

from marshmallow import Schema, fields, pre_load

class BaseSchema(Schema):
    @pre_load
    def check_update_fields(self, data)
        non_update_fields = set([
            fname, fobj for fname, obj in self.fields
            if fobj.metadata.get('can_update') is False
        ])
        return {
            key: value for key, value in data.items()
            if key not in non_update_fields
        }

class UserSchema(BaseSchema):
    name = fields.Str()
    email = fields.Str(can_update=False)

Option 2: class Meta option

from marshmallow import Schema, SchemaOpts, fields, pre_load
class BaseSchemaOpts(SchemaOpts):
    def __init__(self, meta):
        super().__init__(meta)
        self.update_fields = getattr(meta, 'update_fields', set())

class BaseSchema(Schema):
    OPTIONS_CLASS = BaseSchemaOpts

    email = fields.Str(can_update=False)

    @pre_load
    def check_update_fields(self, data)
        non_update_fields = set(self.fields) - set(self.opts.update_fields)
        return {
            key: value for key, value in data.items()
            if key not in non_update_fields
        }

class UserSchema(BaseSchema):

    name = fields.Str()
    email = fields.Str()

    class Meta:
        update_fields = ('name', )

Will either of these meet your use case?

[EdCampion]

Hi Steven,
Thanks very much, leaning towards the second option.