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Data Classes

Dependency + Dataclasses

You can use the built-in dataclasses with Dependency without a problem. Just ensure all fields are optional (ie: they all have default values), so they are not required when creating/init'ing the object.

You can also provide a __post_init__ method on your Dependency subclass to help you initialize the values into a good default state (a standard feature of dataclasses).

The purpose to enable lazily creation of the Dependency object the very first time it's asked for.

Example:

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from xinject import Dependency
from dataclasses import dataclass


@dataclass
class DataResource(Dependency):
    # Making all fields optional, so DataResource can be created lazily:
    my_optional_field: str = None
    another_optional_field: str = "hello!"


# Get current DataResource dependency, print it's another_optional_field;
# will print out `hello!`:
print(DataResource.grab().another_optional_field)

DataResource.grab()

DataResource.grab()

DataResource.grab()
Last update: 2023-04-15