serialization

Due to the dynamic nature of Python objects, it’s necessary to provide some attributes on class declarations that flask-transmute uses when serializing to and from a dictionary.

Two attributes are required:

• a dictionary attribute “transmute_schema” that specifies the structure of the object.
• a static method “from_transmute_dict” that receives a dictionary and should return an instance of the class.

The transmute_schema property is very similar to json-schemas, with the exception of using Python type objects instead of strings to define types:

transmute_schema = {
    "properties": {
        "cards": {
          "type": [Card]
        }
        "name": {"type": str}
    },
    "required": ["name"]
}

The following types may be used:

• [Type] (a list type)
• str
• bool
• NoneType
• int
• any class that is also serializable

The following keys are available:

• properties: this should be a dictionary of string keys and type declaration values, of the format {“type”: cls}.
• required: this should be a list of attributes on the object that are required.

Here’s a complete example:

class Card(object):

    def __init__(self, name, description):
        self.name = name
        self.description = description

    transmute_schema = {
        "properties": {
            "name": {"type": str},
            "description": {"type": str}
        },
        "required": ["name", "description"]
    }

    @staticmethod
    def from_transmute_dict(model):
        return Card(model["name"], model["description"])