| from math import ceil |
| |
| class InvalidPage(Exception): |
| pass |
| |
| class PageNotAnInteger(InvalidPage): |
| pass |
| |
| class EmptyPage(InvalidPage): |
| pass |
| |
| class Paginator(object): |
| def __init__(self, object_list, per_page, orphans=0, allow_empty_first_page=True): |
| self.object_list = object_list |
| self.per_page = per_page |
| self.orphans = orphans |
| self.allow_empty_first_page = allow_empty_first_page |
| self._num_pages = self._count = None |
| |
| def validate_number(self, number): |
| "Validates the given 1-based page number." |
| try: |
| number = int(number) |
| except 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 |
| |
| def page(self, number): |
| "Returns 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 Page(self.object_list[bottom:top], number, self) |
| |
| def _get_count(self): |
| "Returns the total number of objects, across all pages." |
| if self._count is None: |
| try: |
| self._count = 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). |
| self._count = len(self.object_list) |
| return self._count |
| count = property(_get_count) |
| |
| def _get_num_pages(self): |
| "Returns the total number of pages." |
| if self._num_pages is None: |
| if self.count == 0 and not self.allow_empty_first_page: |
| self._num_pages = 0 |
| else: |
| hits = max(1, self.count - self.orphans) |
| self._num_pages = int(ceil(hits / float(self.per_page))) |
| return self._num_pages |
| num_pages = property(_get_num_pages) |
| |
| def _get_page_range(self): |
| """ |
| Returns a 1-based range of pages for iterating through within |
| a template for loop. |
| """ |
| return range(1, self.num_pages + 1) |
| page_range = property(_get_page_range) |
| |
| QuerySetPaginator = Paginator # For backwards-compatibility. |
| |
| class Page(object): |
| 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 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.number + 1 |
| |
| def previous_page_number(self): |
| return self.number - 1 |
| |
| def start_index(self): |
| """ |
| Returns 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): |
| """ |
| Returns 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 |