• Language: en

Source code for django.core.paginator

import collections
import warnings
from math import ceil

from django.utils.functional import cached_property
from django.utils.translation import gettext_lazy as _

class UnorderedObjectListWarning(RuntimeWarning):

[docs]class InvalidPage(Exception): pass
[docs]class PageNotAnInteger(InvalidPage): pass
[docs]class EmptyPage(InvalidPage): pass
[docs]class Paginator: def __init__(self, object_list, per_page, orphans=0, allow_empty_first_page=True): 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 def validate_number(self, number): """Validate the given 1-based page number.""" try: number = int(number) except (TypeError, ValueError): raise PageNotAnInteger(_('That page number is not an integer')) if number < 1: raise EmptyPage(_('That page number is less than 1')) if number > self.num_pages: if number == 1 and self.allow_empty_first_page: pass else: raise EmptyPage(_('That page contains no results')) return 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)
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) @cached_property def count(self): """Return the total number of objects, across all pages.""" try: return self.object_list.count() except (AttributeError, TypeError): # AttributeError if object_list has no count() method. # TypeError if object_list.count() requires arguments # (i.e. is of type list). 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 int(ceil(hits / float(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) 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 )
QuerySetPaginator = Paginator # For backwards-compatibility.
[docs]class Page(collections.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 # 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]
[docs] def has_next(self): return self.number < self.paginator.num_pages
[docs] def has_previous(self): return self.number > 1
[docs] def has_other_pages(self): return self.has_previous() or self.has_next()
[docs] def next_page_number(self): return self.paginator.validate_number(self.number + 1)
[docs] def previous_page_number(self): return self.paginator.validate_number(self.number - 1)
[docs] 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
[docs] 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
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