mirror of
https://github.com/django/django.git
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447 lines
14 KiB
Python
447 lines
14 KiB
Python
import collections.abc
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import inspect
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import warnings
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from asyncio import iscoroutinefunction
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from math import ceil
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from asgiref.sync import sync_to_async
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from django.utils.functional import cached_property
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from django.utils.inspect import method_has_no_args
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from django.utils.translation import gettext_lazy as _
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class UnorderedObjectListWarning(RuntimeWarning):
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pass
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class InvalidPage(Exception):
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pass
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class PageNotAnInteger(InvalidPage):
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pass
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class EmptyPage(InvalidPage):
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pass
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class BasePaginator:
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# Translators: String used to replace omitted page numbers in elided page
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# range generated by paginators, e.g. [1, 2, '…', 5, 6, 7, '…', 9, 10].
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ELLIPSIS = _("…")
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default_error_messages = {
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"invalid_page": _("That page number is not an integer"),
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"min_page": _("That page number is less than 1"),
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"no_results": _("That page contains no results"),
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}
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def __init__(
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self,
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object_list,
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per_page,
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orphans=0,
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allow_empty_first_page=True,
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error_messages=None,
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):
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self.object_list = object_list
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self._check_object_list_is_ordered()
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self.per_page = int(per_page)
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self.orphans = int(orphans)
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self.allow_empty_first_page = allow_empty_first_page
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self.error_messages = (
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self.default_error_messages
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if error_messages is None
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else self.default_error_messages | error_messages
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)
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def _check_object_list_is_ordered(self):
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"""
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Warn if self.object_list is unordered (typically a QuerySet).
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"""
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ordered = getattr(self.object_list, "ordered", None)
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if ordered is not None and not ordered:
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obj_list_repr = (
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"{} {}".format(
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self.object_list.model, self.object_list.__class__.__name__
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)
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if hasattr(self.object_list, "model")
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else "{!r}".format(self.object_list)
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)
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warnings.warn(
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"Pagination may yield inconsistent results with an unordered "
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"object_list: {}.".format(obj_list_repr),
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UnorderedObjectListWarning,
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stacklevel=3,
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)
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def _get_elided_page_range(
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self, number, num_pages, page_range, on_each_side=3, on_ends=2
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):
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"""
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Return a 1-based range of pages with some values elided.
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If the page range is larger than a given size, the whole range is not
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provided and a compact form is returned instead, e.g. for a paginator
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with 50 pages, if page 43 were the current page, the output, with the
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default arguments, would be:
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1, 2, …, 40, 41, 42, 43, 44, 45, 46, …, 49, 50.
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"""
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if num_pages <= (on_each_side + on_ends) * 2:
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for page in page_range:
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yield page
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return
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if number > (1 + on_each_side + on_ends) + 1:
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for page in range(1, on_ends + 1):
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yield page
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yield self.ELLIPSIS
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for page in range(number - on_each_side, number + 1):
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yield page
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else:
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for page in range(1, number + 1):
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yield page
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if number < (num_pages - on_each_side - on_ends) - 1:
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for page in range(number + 1, number + on_each_side + 1):
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yield page
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yield self.ELLIPSIS
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for page in range(num_pages - on_ends + 1, num_pages + 1):
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yield page
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else:
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for page in range(number + 1, num_pages + 1):
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yield page
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def _get_page(self, *args, **kwargs):
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"""
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Return an instance of a single page.
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This hook can be used by subclasses to use an alternative to the
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standard :cls:`Page` object.
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"""
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return Page(*args, **kwargs)
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def _validate_number(self, number, num_pages):
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"""Validate the given 1-based page number."""
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try:
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if isinstance(number, float) and not number.is_integer():
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raise ValueError
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number = int(number)
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except (TypeError, ValueError):
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raise PageNotAnInteger(self.error_messages["invalid_page"])
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if number < 1:
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raise EmptyPage(self.error_messages["min_page"])
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if number > num_pages:
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raise EmptyPage(self.error_messages["no_results"])
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return number
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class Paginator(BasePaginator):
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def __iter__(self):
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for page_number in self.page_range:
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yield self.page(page_number)
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def validate_number(self, number):
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return self._validate_number(number, self.num_pages)
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def get_page(self, number):
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"""
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Return a valid page, even if the page argument isn't a number or isn't
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in range.
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"""
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try:
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number = self.validate_number(number)
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except PageNotAnInteger:
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number = 1
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except EmptyPage:
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number = self.num_pages
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return self.page(number)
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def page(self, number):
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"""Return a Page object for the given 1-based page number."""
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number = self.validate_number(number)
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bottom = (number - 1) * self.per_page
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top = bottom + self.per_page
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if top + self.orphans >= self.count:
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top = self.count
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return self._get_page(self.object_list[bottom:top], number, self)
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@cached_property
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def count(self):
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"""Return the total number of objects, across all pages."""
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c = getattr(self.object_list, "count", None)
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if callable(c) and not inspect.isbuiltin(c) and method_has_no_args(c):
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return c()
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return len(self.object_list)
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@cached_property
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def num_pages(self):
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"""Return the total number of pages."""
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if self.count == 0 and not self.allow_empty_first_page:
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return 0
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hits = max(1, self.count - self.orphans)
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return ceil(hits / self.per_page)
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@property
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def page_range(self):
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"""
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Return a 1-based range of pages for iterating through within
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a template for loop.
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"""
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return range(1, self.num_pages + 1)
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def get_elided_page_range(self, number=1, *, on_each_side=3, on_ends=2):
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number = self.validate_number(number)
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yield from self._get_elided_page_range(
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number, self.num_pages, self.page_range, on_each_side, on_ends
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)
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class AsyncPaginator(BasePaginator):
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def __init__(
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self,
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object_list,
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per_page,
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orphans=0,
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allow_empty_first_page=True,
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error_messages=None,
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):
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super().__init__(
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object_list, per_page, orphans, allow_empty_first_page, error_messages
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)
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self._cache_acount = None
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self._cache_anum_pages = None
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async def __aiter__(self):
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page_range = await self.apage_range()
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for page_number in page_range:
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yield await self.apage(page_number)
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async def avalidate_number(self, number):
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num_pages = await self.anum_pages()
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return self._validate_number(number, num_pages)
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async def aget_page(self, number):
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"""See Paginator.get_page()."""
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try:
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number = await self.avalidate_number(number)
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except PageNotAnInteger:
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number = 1
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except EmptyPage:
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number = await self.anum_pages()
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return await self.apage(number)
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async def apage(self, number):
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"""See Paginator.page()."""
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number = await self.avalidate_number(number)
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bottom = (number - 1) * self.per_page
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top = bottom + self.per_page
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count = await self.acount()
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if top + self.orphans >= count:
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top = count
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return self._get_page(self.object_list[bottom:top], number, self)
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def _get_page(self, *args, **kwargs):
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return AsyncPage(*args, **kwargs)
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async def acount(self):
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"""See Paginator.count()."""
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if self._cache_acount is not None:
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return self._cache_acount
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c = getattr(self.object_list, "acount", None)
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if (
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iscoroutinefunction(c)
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and not inspect.isbuiltin(c)
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and method_has_no_args(c)
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):
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count = await c()
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else:
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count = len(self.object_list)
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self._cache_acount = count
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return count
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async def anum_pages(self):
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"""See Paginator.num_pages()."""
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if self._cache_anum_pages is not None:
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return self._cache_anum_pages
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count = await self.acount()
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if count == 0 and not self.allow_empty_first_page:
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self._cache_anum_pages = 0
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return self._cache_anum_pages
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hits = max(1, count - self.orphans)
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num_pages = ceil(hits / self.per_page)
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self._cache_anum_pages = num_pages
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return num_pages
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async def apage_range(self):
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"""See Paginator.page_range()"""
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num_pages = await self.anum_pages()
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return range(1, num_pages + 1)
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async def aget_elided_page_range(self, number=1, *, on_each_side=3, on_ends=2):
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number = await self.avalidate_number(number)
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num_pages = await self.anum_pages()
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page_range = await self.apage_range()
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for page in self._get_elided_page_range(
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number, num_pages, page_range, on_each_side, on_ends
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):
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yield page
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class Page(collections.abc.Sequence):
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def __init__(self, object_list, number, paginator):
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self.object_list = object_list
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self.number = number
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self.paginator = paginator
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def __repr__(self):
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return "<Page %s of %s>" % (self.number, self.paginator.num_pages)
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def __len__(self):
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return len(self.object_list)
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def __getitem__(self, index):
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if not isinstance(index, (int, slice)):
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raise TypeError(
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"Page indices must be integers or slices, not %s."
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% type(index).__name__
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)
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# The object_list is converted to a list so that if it was a QuerySet
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# it won't be a database hit per __getitem__.
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if not isinstance(self.object_list, list):
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self.object_list = list(self.object_list)
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return self.object_list[index]
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def has_next(self):
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return self.number < self.paginator.num_pages
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def has_previous(self):
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return self.number > 1
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def has_other_pages(self):
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return self.has_previous() or self.has_next()
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def next_page_number(self):
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return self.paginator.validate_number(self.number + 1)
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def previous_page_number(self):
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return self.paginator.validate_number(self.number - 1)
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def start_index(self):
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"""
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Return the 1-based index of the first object on this page,
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relative to total objects in the paginator.
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"""
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# Special case, return zero if no items.
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if self.paginator.count == 0:
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return 0
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return (self.paginator.per_page * (self.number - 1)) + 1
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def end_index(self):
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"""
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Return the 1-based index of the last object on this page,
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relative to total objects found (hits).
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"""
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# Special case for the last page because there can be orphans.
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if self.number == self.paginator.num_pages:
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return self.paginator.count
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return self.number * self.paginator.per_page
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class AsyncPage:
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def __init__(self, object_list, number, paginator):
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self.object_list = object_list
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self.number = number
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self.paginator = paginator
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def __repr__(self):
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return "<Async Page %s>" % self.number
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async def __aiter__(self):
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if hasattr(self.object_list, "__aiter__"):
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async for obj in self.object_list:
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yield obj
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else:
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for obj in self.object_list:
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yield obj
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def __len__(self):
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if not isinstance(self.object_list, list):
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raise TypeError(
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"AsyncPage.aget_object_list() must be awaited before calling len()."
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)
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return len(self.object_list)
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def __reversed__(self):
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if not isinstance(self.object_list, list):
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raise TypeError(
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"AsyncPage.aget_object_list() "
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"must be awaited before calling reversed()."
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)
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return reversed(self.object_list)
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def __getitem__(self, index):
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if not isinstance(index, (int, slice)):
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raise TypeError(
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"AsyncPage indices must be integers or slices, not %s."
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% type(index).__name__
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)
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if not isinstance(self.object_list, list):
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raise TypeError(
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"AsyncPage.aget_object_list() must be awaited before using indexing."
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)
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return self.object_list[index]
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async def aget_object_list(self):
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"""
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Returns self.object_list as a list.
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This method must be awaited before AsyncPage can be
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treated as a sequence of self.object_list.
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"""
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if not isinstance(self.object_list, list):
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if hasattr(self.object_list, "__aiter__"):
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self.object_list = [obj async for obj in self.object_list]
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else:
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self.object_list = await sync_to_async(list)(self.object_list)
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return self.object_list
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async def ahas_next(self):
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num_pages = await self.paginator.anum_pages()
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return self.number < num_pages
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async def ahas_previous(self):
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return self.number > 1
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async def ahas_other_pages(self):
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has_previous = await self.ahas_previous()
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has_next = await self.ahas_next()
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return has_previous or has_next
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async def anext_page_number(self):
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return await self.paginator.avalidate_number(self.number + 1)
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async def aprevious_page_number(self):
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return await self.paginator.avalidate_number(self.number - 1)
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async def astart_index(self):
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"""See Page.start_index()."""
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count = await self.paginator.acount()
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if count == 0:
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return 0
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return (self.paginator.per_page * (self.number - 1)) + 1
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async def aend_index(self):
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"""See Page.end_index()."""
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num_pages = await self.paginator.anum_pages()
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if self.number == num_pages:
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return await self.paginator.acount()
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return self.number * self.paginator.per_page
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