Resource Meta options

Meta options are flags that can be applied to a resource to affect it’s behaviour or how it is dealt with via Odin tools.

Give your resource metadata by using an inner class Meta, eg:

class Book(odin.Resource):
    class Meta:
        name_space = "library"
        verbose_name_plural = "Books"

    title = odin.StringField()

Resource metadata is “anything that’s not a field”, module_name and human-readable plural names (verbose_name and verbose_name_plural). None are required, and adding class Meta to a resource is completely optional.

Meta Options

name

Override the name of a resource. This is the codecs when serialising/de-serialising as a name to represent the resource. The default name is the name of the class used to define the resource.

name_space

The name space is an optional string value that is used to group a set of common resources. Typically a namespace should be in the form of dot-atoms eg: university.library or org.poweredbypenguins. The default is no namespace.

verbose_name

A long version of the name for used when displaying a resource or in generated documentation. The default verbose_name is a name attribute that has been converted to lower case and spaces put before each upper case character eg: LibraryBook -> “library book”

verbose_name_plural

A pluralised version of the verbose_name. The default is to use the verbose name and append an ‘s’ character. In the case of many words this does not work correctly so this attribute allows for the default behaviour to be overridden.

abstract

Marks the current resource as an abstract resource. See the section Abstract base classes for more detail of the abstract attribute. The default value for abstract is False.

doc_group

A grouping for documentation purposes. This is purely optional but is useful for grouping common elements together. The default value for doc_group is None.

type_field

The field used to identify the object type during serialisation/de-serialisation. This defaults to the $ character.

key_field_name

Used by external libraries like baldr for identifying what field is used as the key field to uniquely identify a resource instance (a good example would be an ID field).

key_field_names

Similar to the key_field_name but for defining multi-part keys.

field_name_format

Provide a function that can be used to format field names. Field names are used to identify values when a resource serialised/deserialised.

For example to use camelCase names specify the following option:

from odin.utils import snake_to_camel

class MyResource(Resource):
    class Meta:
        field_name_format = snake_to_camel

field_sorting

Used to customise how fields are sorted (primarily affects the order fields will be exported during serialisation) during inheritance. The default behaviour is to sort fields in the child resource before appending the fields from the parent resource(s).

Setting this option to True will cause field sorting to happen after all of the fields have been attached using the default sort method. The default method sorts the fields by the order they are defined.

Supplying a callable allows for customisation of the field sorting eg sort by name:

def sort_by_name(fields):
    return sorted(fields, key=lambda f: f.name)

class MyResource(Resource):
    class Meta:
        field_sorting = sort_by_name

user_data

Additional data that can be added to metadata. This can be used to provide additional parameters beyond those supported by odin for a custom application use-case.

For example:

class MyResource(Resource):
    class Meta:
        user_data = {
            "custom": "my-custom-value",
        }

allow_field_shadowing

Allow fields to be shadow fields with the same name in a parent resource.

Setting this option to True will allow fields to be shadowed without an exception being raised. The default behaviour is to raise an exception if a field is shadowed.