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120 lines
3.9 KiB
120 lines
3.9 KiB
from math import ceil |
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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 Paginator(object): |
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def __init__(self, object_list, per_page, orphans=0, allow_empty_first_page=True): |
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self.object_list = object_list |
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self.per_page = per_page |
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self.orphans = orphans |
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self.allow_empty_first_page = allow_empty_first_page |
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self._num_pages = self._count = None |
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def validate_number(self, number): |
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"Validates the given 1-based page number." |
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try: |
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number = int(number) |
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except ValueError: |
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raise PageNotAnInteger('That page number is not an integer') |
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if number < 1: |
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raise EmptyPage('That page number is less than 1') |
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if number > self.num_pages: |
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if number == 1 and self.allow_empty_first_page: |
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pass |
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else: |
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raise EmptyPage('That page contains no results') |
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return number |
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def page(self, number): |
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"Returns 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 Page(self.object_list[bottom:top], number, self) |
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def _get_count(self): |
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"Returns the total number of objects, across all pages." |
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if self._count is None: |
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try: |
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self._count = self.object_list.count() |
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except (AttributeError, TypeError): |
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# AttributeError if object_list has no count() method. |
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# TypeError if object_list.count() requires arguments |
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# (i.e. is of type list). |
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self._count = len(self.object_list) |
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return self._count |
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count = property(_get_count) |
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def _get_num_pages(self): |
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"Returns the total number of pages." |
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if self._num_pages is None: |
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if self.count == 0 and not self.allow_empty_first_page: |
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self._num_pages = 0 |
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else: |
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hits = max(1, self.count - self.orphans) |
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self._num_pages = int(ceil(hits / float(self.per_page))) |
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return self._num_pages |
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num_pages = property(_get_num_pages) |
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def _get_page_range(self): |
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""" |
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Returns 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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page_range = property(_get_page_range) |
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QuerySetPaginator = Paginator # For backwards-compatibility. |
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class Page(object): |
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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 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.number + 1 |
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def previous_page_number(self): |
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return self.number - 1 |
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def start_index(self): |
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""" |
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Returns 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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Returns 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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