import collections.abc
import inspect
import warnings
from math import ceil
from asgiref.sync import iscoroutinefunction, sync_to_async
from django.utils.deprecation import RemovedInDjango70Warning
from django.utils.functional import cached_property
from django.utils.inspect import method_has_no_args
from django.utils.translation import gettext_lazy as _
class UnorderedObjectListWarning(RuntimeWarning):
pass
class InvalidPage(Exception):
pass
class PageNotAnInteger(InvalidPage):
pass
class EmptyPage(InvalidPage):
pass
class BasePaginator:
# Translators: String used to replace omitted page numbers in elided page
# range generated by paginators, e.g. [1, 2, '…', 5, 6, 7, '…', 9, 10].
ELLIPSIS = _("…")
default_error_messages = {
"invalid_page": _("That page number is not an integer"),
"min_page": _("That page number is less than 1"),
"no_results": _("That page contains no results"),
}
def __init__(
self,
object_list,
per_page,
orphans=0,
allow_empty_first_page=True,
error_messages=None,
):
self.object_list = object_list
self._check_object_list_is_ordered()
self.per_page = int(per_page)
self.orphans = int(orphans)
self.allow_empty_first_page = allow_empty_first_page
self.error_messages = (
self.default_error_messages
if error_messages is None
else self.default_error_messages | error_messages
)
if self.per_page <= self.orphans:
# RemovedInDjango70Warning: When the deprecation ends, replace
# with:
# raise ValueError(
# "The orphans argument cannot be larger than or equal to the "
# "per_page argument."
# )
msg = (
"Support for the orphans argument being larger than or equal to the "
"per_page argument is deprecated. This will raise a ValueError in "
"Django 7.0."
)
warnings.warn(msg, category=RemovedInDjango70Warning, stacklevel=2)
def _check_object_list_is_ordered(self):
"""
Warn if self.object_list is unordered (typically a QuerySet).
"""
ordered = getattr(self.object_list, "ordered", None)
if ordered is not None and not ordered:
obj_list_repr = (
"{} {}".format(
self.object_list.model, self.object_list.__class__.__name__
)
if hasattr(self.object_list, "model")
else "{!r}".format(self.object_list)
)
warnings.warn(
"Pagination may yield inconsistent results with an unordered "
"object_list: {}.".format(obj_list_repr),
UnorderedObjectListWarning,
stacklevel=3,
)
def _get_elided_page_range(
self, number, num_pages, page_range, on_each_side=3, on_ends=2
):
"""
Return a 1-based range of pages with some values elided.
If the page range is larger than a given size, the whole range is not
provided and a compact form is returned instead, e.g. for a paginator
with 50 pages, if page 43 were the current page, the output, with the
default arguments, would be:
1, 2, …, 40, 41, 42, 43, 44, 45, 46, …, 49, 50.
"""
if num_pages <= (on_each_side + on_ends) * 2:
for page in page_range:
yield page
return
if number > (1 + on_each_side + on_ends) + 1:
for page in range(1, on_ends + 1):
yield page
yield self.ELLIPSIS
for page in range(number - on_each_side, number + 1):
yield page
else:
for page in range(1, number + 1):
yield page
if number < (num_pages - on_each_side - on_ends) - 1:
for page in range(number + 1, number + on_each_side + 1):
yield page
yield self.ELLIPSIS
for page in range(num_pages - on_ends + 1, num_pages + 1):
yield page
else:
for page in range(number + 1, num_pages + 1):
yield page
def _get_page(self, *args, **kwargs):
"""
Return an instance of a single page.
This hook can be used by subclasses to use an alternative to the
standard :cls:`Page` object.
"""
return Page(*args, **kwargs)
def _validate_number(self, number, num_pages):
"""Validate the given 1-based page number."""
try:
if isinstance(number, float) and not number.is_integer():
raise ValueError
number = int(number)
except (TypeError, ValueError):
raise PageNotAnInteger(self.error_messages["invalid_page"])
if number < 1:
raise EmptyPage(self.error_messages["min_page"])
if number > num_pages:
raise EmptyPage(self.error_messages["no_results"])
return number
[docs]
class Paginator(BasePaginator):
def __iter__(self):
for page_number in self.page_range:
yield self.page(page_number)
[docs]
def validate_number(self, number):
return self._validate_number(number, self.num_pages)
[docs]
def get_page(self, number):
"""
Return a valid page, even if the page argument isn't a number or isn't
in range.
"""
try:
number = self.validate_number(number)
except PageNotAnInteger:
number = 1
except EmptyPage:
number = self.num_pages
return self.page(number)
[docs]
def page(self, number):
"""Return a Page object for the given 1-based page number."""
number = self.validate_number(number)
bottom = (number - 1) * self.per_page
top = bottom + self.per_page
if top + self.orphans >= self.count:
top = self.count
return self._get_page(self.object_list[bottom:top], number, self)
@cached_property
def count(self):
"""Return the total number of objects, across all pages."""
c = getattr(self.object_list, "count", None)
if callable(c) and not inspect.isbuiltin(c) and method_has_no_args(c):
return c()
return len(self.object_list)
@cached_property
def num_pages(self):
"""Return the total number of pages."""
if self.count == 0 and not self.allow_empty_first_page:
return 0
hits = max(1, self.count - self.orphans)
return ceil(hits / self.per_page)
@property
def page_range(self):
"""
Return a 1-based range of pages for iterating through within
a template for loop.
"""
return range(1, self.num_pages + 1)
[docs]
def get_elided_page_range(self, number=1, *, on_each_side=3, on_ends=2):
number = self.validate_number(number)
yield from self._get_elided_page_range(
number, self.num_pages, self.page_range, on_each_side, on_ends
)
class AsyncPaginator(BasePaginator):
def __init__(
self,
object_list,
per_page,
orphans=0,
allow_empty_first_page=True,
error_messages=None,
):
super().__init__(
object_list, per_page, orphans, allow_empty_first_page, error_messages
)
self._cache_acount = None
self._cache_anum_pages = None
async def __aiter__(self):
page_range = await self.apage_range()
for page_number in page_range:
yield await self.apage(page_number)
async def avalidate_number(self, number):
num_pages = await self.anum_pages()
return self._validate_number(number, num_pages)
async def aget_page(self, number):
"""See Paginator.get_page()."""
try:
number = await self.avalidate_number(number)
except PageNotAnInteger:
number = 1
except EmptyPage:
number = await self.anum_pages()
return await self.apage(number)
async def apage(self, number):
"""See Paginator.page()."""
number = await self.avalidate_number(number)
bottom = (number - 1) * self.per_page
top = bottom + self.per_page
count = await self.acount()
if top + self.orphans >= count:
top = count
return self._get_page(self.object_list[bottom:top], number, self)
def _get_page(self, *args, **kwargs):
return AsyncPage(*args, **kwargs)
async def acount(self):
"""See Paginator.count()."""
if self._cache_acount is not None:
return self._cache_acount
c = getattr(self.object_list, "acount", None)
if (
iscoroutinefunction(c)
and not inspect.isbuiltin(c)
and method_has_no_args(c)
):
count = await c()
else:
count = len(self.object_list)
self._cache_acount = count
return count
async def anum_pages(self):
"""See Paginator.num_pages()."""
if self._cache_anum_pages is not None:
return self._cache_anum_pages
count = await self.acount()
if count == 0 and not self.allow_empty_first_page:
self._cache_anum_pages = 0
return self._cache_anum_pages
hits = max(1, count - self.orphans)
num_pages = ceil(hits / self.per_page)
self._cache_anum_pages = num_pages
return num_pages
async def apage_range(self):
"""See Paginator.page_range()"""
num_pages = await self.anum_pages()
return range(1, num_pages + 1)
async def aget_elided_page_range(self, number=1, *, on_each_side=3, on_ends=2):
number = await self.avalidate_number(number)
num_pages = await self.anum_pages()
page_range = await self.apage_range()
for page in self._get_elided_page_range(
number, num_pages, page_range, on_each_side, on_ends
):
yield page
class Page(collections.abc.Sequence):
def __init__(self, object_list, number, paginator):
self.object_list = object_list
self.number = number
self.paginator = paginator
def __repr__(self):
return "<Page %s of %s>" % (self.number, self.paginator.num_pages)
def __len__(self):
return len(self.object_list)
def __getitem__(self, index):
if not isinstance(index, (int, slice)):
raise TypeError(
"Page indices must be integers or slices, not %s."
% type(index).__name__
)
# The object_list is converted to a list so that if it was a QuerySet
# it won't be a database hit per __getitem__.
if not isinstance(self.object_list, list):
self.object_list = list(self.object_list)
return self.object_list[index]
def has_next(self):
return self.number < self.paginator.num_pages
def has_previous(self):
return self.number > 1
def has_other_pages(self):
return self.has_previous() or self.has_next()
def next_page_number(self):
return self.paginator.validate_number(self.number + 1)
def previous_page_number(self):
return self.paginator.validate_number(self.number - 1)
def start_index(self):
"""
Return the 1-based index of the first object on this page,
relative to total objects in the paginator.
"""
# Special case, return zero if no items.
if self.paginator.count == 0:
return 0
return (self.paginator.per_page * (self.number - 1)) + 1
def end_index(self):
"""
Return the 1-based index of the last object on this page,
relative to total objects found (hits).
"""
# Special case for the last page because there can be orphans.
if self.number == self.paginator.num_pages:
return self.paginator.count
return self.number * self.paginator.per_page
class AsyncPage:
def __init__(self, object_list, number, paginator):
self.object_list = object_list
self.number = number
self.paginator = paginator
def __repr__(self):
return "<Async Page %s>" % self.number
async def __aiter__(self):
if hasattr(self.object_list, "__aiter__"):
async for obj in self.object_list:
yield obj
else:
for obj in self.object_list:
yield obj
def __len__(self):
if not isinstance(self.object_list, list):
raise TypeError(
"AsyncPage.aget_object_list() must be awaited before calling len()."
)
return len(self.object_list)
def __reversed__(self):
if not isinstance(self.object_list, list):
raise TypeError(
"AsyncPage.aget_object_list() "
"must be awaited before calling reversed()."
)
return reversed(self.object_list)
def __getitem__(self, index):
if not isinstance(index, (int, slice)):
raise TypeError(
"AsyncPage indices must be integers or slices, not %s."
% type(index).__name__
)
if not isinstance(self.object_list, list):
raise TypeError(
"AsyncPage.aget_object_list() must be awaited before using indexing."
)
return self.object_list[index]
async def aget_object_list(self):
"""
Returns self.object_list as a list.
This method must be awaited before AsyncPage can be
treated as a sequence of self.object_list.
"""
if not isinstance(self.object_list, list):
if hasattr(self.object_list, "__aiter__"):
self.object_list = [obj async for obj in self.object_list]
else:
self.object_list = await sync_to_async(list)(self.object_list)
return self.object_list
async def ahas_next(self):
num_pages = await self.paginator.anum_pages()
return self.number < num_pages
async def ahas_previous(self):
return self.number > 1
async def ahas_other_pages(self):
has_previous = await self.ahas_previous()
has_next = await self.ahas_next()
return has_previous or has_next
async def anext_page_number(self):
return await self.paginator.avalidate_number(self.number + 1)
async def aprevious_page_number(self):
return await self.paginator.avalidate_number(self.number - 1)
async def astart_index(self):
"""See Page.start_index()."""
count = await self.paginator.acount()
if count == 0:
return 0
return (self.paginator.per_page * (self.number - 1)) + 1
async def aend_index(self):
"""See Page.end_index()."""
num_pages = await self.paginator.anum_pages()
if self.number == num_pages:
return await self.paginator.acount()
return self.number * self.paginator.per_page
