from __future__ import annotations
from dataclasses import dataclass, field
from uuid import NAMESPACE_URL, UUID, uuid5
from eventsourcing.domain import Aggregate, DomainEvent, event
from examples.contentmanagement.utils import apply_diff, create_diff
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@dataclass
class Page(Aggregate):
title: str
"""The title of the page."""
slug: str
"""The slug of the page - used in URLs."""
body: str
"""The proper content of the page."""
modified_by: UUID | None = field(init=False)
"""The ID of the user who last modified the page."""
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class Event(Aggregate.Event):
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def apply(self, aggregate: Page) -> None:
"""Sets the aggregate's `modified_by` attribute to the
value of the event's metadata `user_id` value.
"""
aggregate.modified_by = self.get_user_id()
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def get_user_id(self) -> UUID:
return UUID(self.metadata["user_id"])
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@event("SlugUpdated")
def update_slug(self, slug: str) -> None:
self.slug = slug
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@event("TitleUpdated")
def update_title(self, title: str) -> None:
self.title = title
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def update_body(self, body: str) -> None:
diff = create_diff(old=self.body, new=body)
self._update_body(diff=diff)
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class Created(Aggregate.Created, Event):
title: str
slug: str
body: str
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class BodyUpdated(Event):
diff: str
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@event(BodyUpdated)
def _update_body(self, diff: str) -> None:
new_body = apply_diff(old=self.body, diff=diff)
self.body = new_body
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@dataclass
class Slug(Aggregate):
name: str
page_id: UUID | None
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class Event(Aggregate.Event):
pass
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@staticmethod
def create_id(name: str) -> UUID:
return uuid5(NAMESPACE_URL, f"/slugs/{name}")
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@event("PageUpdated")
def update_page(self, page_id: UUID | None) -> None:
self.page_id = page_id
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class PageLogged(DomainEvent):
page_id: UUID