calamus is a library built on top of marshmallow to allow (de-)Serialization of Python classes to Json-LD

calamus releases and development versions are available from PyPI. You can install it using any tool that knows how to handle PyPI packages.

With pip:

$ pip install calamus

Assuming you have a class like

class Book:
    def __init__(self, _id, name):
        self._id = _id
        self.name = name

You can declare a schema for serialization like

schema = fields.Namespace("http://schema.org/")

class BookSchema(JsonLDSchema):
    _id = fields.Id()
    name = fields.String(schema.name)

    class Meta:
        rdf_type = schema.Book
        model = Book

The fields.Namespace class represents an ontology namespace.

Make sure to set rdf_type to the RDF triple type you want get and model to the python class this schema applies to.

You can now easily serialize python classes to Json-LD

book = Book(_id="http://example.com/books/1", name="Ilias")
jsonld_dict = BookSchema().dump(book)
#{
#    "@id": "http://example.com/books/1",
#    "@type": "http://schema.org/Book",
#    "http://schema.org/name": "Ilias",
#}

jsonld_string = BookSchema().dumps(book)
#'{"@id": "http://example.com/books/1", "http://schema.org/name": "Ilias", "@type": "http://schema.org/Book"}')

You can also easily deserialize Json-LD to python objects

data = {
    "@id": "http://example.com/books/1",
    "@type": "http://schema.org/Book",
    "http://schema.org/name": "Ilias",
}
book = BookSchema().load(data)
#<Book(_id="http://example.com/books/1", name="Ilias")>