marshmallow-always-list-field

This is a small package that will ensure that your marshmallow will alway contain list.

Some times you want to ensure that your marshmallow schema will always return a list, even if the input is a single item. Just to make an API response consistent.

Installation

pip install marshmallow-always-list-field

Usage

from marshmallow_always_list_field import AlwaysListField

class MySchema(Schema):
    my_list = AlwaysListField(fields.String())

If input is:

{
    "my_list": "foo"
}

it will result with:

{
    "my_list": ["foo"]
}

This will work with nested fields as well.

If nested field is:

class NestedSchema(Schema):
    my_list = AlwaysListField(fields.String())

class MySchema(Schema):
    nested = fields.Nested(NestedSchema)

and input is:

{
    "nested": {
        "my_list": "foo"
    }
}

result will be:

{
    "nested": {
        "my_list": ["foo"]
    }
}

Additionally you can do something like this:

class NestedSchema(Schema):
    data = fields.String()

class SampleSchema(Schema):
    nested = AlwaysListField(fields.Nested(NestedSchema))

assert result == {"nested": [{"data": "hello"}]}

and input is:

{
    "nested": {
        "data": "hello"
    }
}

result will be:

{
    "nested": [{"data": "hello"}]
}

Development

pip install -r requirements.txt

Testing

pytest

License

MIT

Author

Dominik Szymanski