58 lines
1.9 KiB
Python
58 lines
1.9 KiB
Python
from django.db import models
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class MastodonPaginator:
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"""
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Paginates in the Mastodon style (max_id, min_id, etc)
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"""
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def __init__(
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self,
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anchor_model: type[models.Model],
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sort_attribute: str = "created",
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default_limit: int = 20,
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max_limit: int = 40,
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):
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self.anchor_model = anchor_model
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self.sort_attribute = sort_attribute
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self.default_limit = default_limit
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self.max_limit = max_limit
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def paginate(
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self,
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queryset,
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min_id: str | None,
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max_id: str | None,
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since_id: str | None,
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limit: int | None,
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):
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if max_id:
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try:
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anchor = self.anchor_model.objects.get(pk=max_id)
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except self.anchor_model.DoesNotExist:
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return []
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queryset = queryset.filter(
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**{self.sort_attribute + "__lt": getattr(anchor, self.sort_attribute)}
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)
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if since_id:
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try:
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anchor = self.anchor_model.objects.get(pk=since_id)
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except self.anchor_model.DoesNotExist:
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return []
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queryset = queryset.filter(
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**{self.sort_attribute + "__gt": getattr(anchor, self.sort_attribute)}
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)
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if min_id:
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# Min ID requires items _immediately_ newer than specified, so we
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# invert the ordering to accomodate
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try:
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anchor = self.anchor_model.objects.get(pk=min_id)
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except self.anchor_model.DoesNotExist:
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return []
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queryset = queryset.filter(
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**{self.sort_attribute + "__gt": getattr(anchor, self.sort_attribute)}
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).order_by(self.sort_attribute)
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else:
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queryset = queryset.order_by("-" + self.sort_attribute)
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return list(queryset[: min(limit or self.default_limit, self.max_limit)])
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