126 lines
4.2 KiB
Python
126 lines
4.2 KiB
Python
from django.db import models
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from activities.models import Post, PostInteraction, PostInteractionStates, PostStates
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from users.models import Identity
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class PostService:
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"""
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High-level operations on Posts
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"""
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def __init__(self, post: Post):
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self.post = post
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def interact_as(self, identity: Identity, type: str):
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"""
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Performs an interaction on this Post
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"""
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interaction = PostInteraction.objects.get_or_create(
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type=type,
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identity=identity,
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post=self.post,
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)[0]
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if interaction.state not in PostInteractionStates.group_active():
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interaction.transition_perform(PostInteractionStates.new)
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def uninteract_as(self, identity, type):
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"""
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Undoes an interaction on this Post
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"""
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for interaction in PostInteraction.objects.filter(
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type=type,
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identity=identity,
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post=self.post,
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):
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interaction.transition_perform(PostInteractionStates.undone)
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def like_as(self, identity: Identity):
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self.interact_as(identity, PostInteraction.Types.like)
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def unlike_as(self, identity: Identity):
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self.uninteract_as(identity, PostInteraction.Types.like)
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def boost_as(self, identity: Identity):
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self.interact_as(identity, PostInteraction.Types.boost)
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def unboost_as(self, identity: Identity):
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self.uninteract_as(identity, PostInteraction.Types.boost)
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@classmethod
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def queryset(cls):
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"""
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Returns the base queryset to use for fetching posts efficiently.
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"""
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return (
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Post.objects.not_hidden()
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.prefetch_related(
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"attachments",
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"mentions",
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"emojis",
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)
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.select_related(
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"author",
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"author__domain",
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)
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.annotate(
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like_count=models.Count(
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"interactions",
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filter=models.Q(
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interactions__type=PostInteraction.Types.like,
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interactions__state__in=PostInteractionStates.group_active(),
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),
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),
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boost_count=models.Count(
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"interactions",
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filter=models.Q(
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interactions__type=PostInteraction.Types.boost,
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interactions__state__in=PostInteractionStates.group_active(),
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),
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),
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)
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)
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def context(self, identity: Identity | None) -> tuple[list[Post], list[Post]]:
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"""
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Returns ancestor/descendant information.
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Ancestors are guaranteed to be in order from closest to furthest.
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Descendants are in depth-first order, starting with closest.
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If identity is provided, includes mentions/followers-only posts they
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can see. Otherwise, shows unlisted and above only.
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"""
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num_ancestors = 10
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num_descendants = 50
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# Retrieve ancestors via parent walk
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ancestors: list[Post] = []
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ancestor = self.post
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while ancestor.in_reply_to and len(ancestors) < num_ancestors:
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ancestor = self.queryset().get(object_uri=ancestor.in_reply_to)
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if ancestor is None:
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break
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if ancestor.state in [PostStates.deleted, PostStates.deleted_fanned_out]:
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break
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ancestors.append(ancestor)
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# Retrieve descendants via breadth-first-search
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descendants: list[Post] = []
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queue = [self.post]
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while queue and len(descendants) < num_descendants:
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node = queue.pop()
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child_queryset = (
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self.queryset()
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.filter(in_reply_to=node.object_uri)
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.order_by("published")
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)
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if identity:
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child_queryset = child_queryset.visible_to(
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identity=identity, include_replies=True
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)
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else:
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child_queryset = child_queryset.unlisted(include_replies=True)
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for child in child_queryset:
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descendants.append(child)
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queue.append(child)
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return ancestors, descendants
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