Code

Ticket #2575: better_paginator.2.patch

File better_paginator.2.patch, 5.1 KB (added by SmileyChris, 8 years ago)

oops, typos

  • django/core/paginator.py

     
    1 from math import ceil 
    2  
    31class InvalidPage(Exception): 
    42    pass 
    53 
    64class ObjectPaginator(object): 
    75    """ 
    8     This class makes pagination easy. Feed it a QuerySet, plus the number of 
    9     objects you want on each page. Then read the hits and pages properties to 
     6    This class makes pagination easy. Feed it a QuerySet or list, plus the number 
     7    of objects you want on each page. Then read the hits and pages properties to 
    108    see how many pages it involves. Call get_page with a page number (starting 
    119    at 0) to get back a list of objects for that page. 
    1210 
    1311    Finally, check if a page number has a next/prev page using 
    1412    has_next_page(page_number) and has_previous_page(page_number). 
     13     
     14    Use orphan to avoid small final pages. For example: 
     15    13 records, num_per_page=10, orphan=2 --> pages==2, len(self.get_page(0))==10 
     16    12 records, num_per_page=10, orphan=2 --> pages==1, len(self.get_page(0))==12 
    1517    """ 
    16     def __init__(self, query_set, num_per_page): 
     18    def __init__(self, query_set, num_per_page, orphan=0): 
    1719        self.query_set = query_set 
    1820        self.num_per_page = num_per_page 
    19         self._hits, self._pages = None, None 
    20         self._has_next = {} # Caches page_number -> has_next_boolean 
     21        self.orphan = orphan 
     22        self._hits = self._pages = None 
    2123 
    22     def get_page(self, page_number): 
     24    def validate_page_number(self, page_number): 
    2325        try: 
    2426            page_number = int(page_number) 
    2527        except ValueError: 
    2628            raise InvalidPage 
    27         if page_number < 0: 
     29        if page_number < 0 or page_number > self.pages - 1: 
    2830            raise InvalidPage 
     31        return page_number 
    2932 
    30         # Retrieve one extra record, and check for the existence of that extra 
    31         # record to determine whether there's a next page. 
    32         limit = self.num_per_page + 1 
    33         offset = page_number * self.num_per_page 
     33    def get_page(self, page_number): 
     34        page_number = self.validate_page_number(page_number) 
     35        bottom = page_number * self.num_per_page 
     36        top = bottom + self.num_per_page 
     37        if top + self.orphan >= self.hits: 
     38            top = self.hits 
     39        return self.query_set[bottom:top] 
    3440 
    35         object_list = list(self.query_set[offset:offset+limit]) 
    36  
    37         if not object_list: 
    38             raise InvalidPage 
    39  
    40         self._has_next[page_number] = (len(object_list) > self.num_per_page) 
    41         return object_list[:self.num_per_page] 
    42  
    4341    def has_next_page(self, page_number): 
    4442        "Does page $page_number have a 'next' page?" 
    45         if not self._has_next.has_key(page_number): 
    46             if self._pages is None: 
    47                 offset = (page_number + 1) * self.num_per_page 
    48                 self._has_next[page_number] = len(self.query_set[offset:offset+1]) > 0 
    49             else: 
    50                 self._has_next[page_number] = page_number < (self.pages - 1) 
    51         return self._has_next[page_number] 
     43        return page_number < self.pages - 1 
    5244 
    5345    def has_previous_page(self, page_number): 
    5446        return page_number > 0 
     
    5850        Returns the 1-based index of the first object on the given page, 
    5951        relative to total objects found (hits). 
    6052        """ 
    61         if page_number == 0: 
    62             return 1 
     53        page_number = self.validate_page_number(page_number) 
    6354        return (self.num_per_page * page_number) + 1 
    6455 
    6556    def last_on_page(self, page_number): 
     
    6758        Returns the 1-based index of the last object on the given page, 
    6859        relative to total objects found (hits). 
    6960        """ 
    70         if page_number == 0 and self.num_per_page >= self._hits: 
    71             return self._hits 
    72         elif page_number == (self._pages - 1) and (page_number + 1) * self.num_per_page > self._hits: 
    73             return self._hits 
    74         return (page_number + 1) * self.num_per_page 
     61        page_number = self.validate_page_number(page_number) 
     62        page_number += 1   # 1-base 
     63        if page_number == self.pages: 
     64            return self.hits 
     65        return page_number * self.num_per_page 
    7566 
    7667    def _get_hits(self): 
    7768        if self._hits is None: 
    78             self._hits = self.query_set.count() 
     69            # Try .count() or fall back to len(). 
     70            try: 
     71                self._hits = int(self.query_set.count()) 
     72            except (AttributeError, TypeError, ValueError): 
     73                # AttributeError if query_set has no object count. 
     74                # TypeError if query_set.count() required arguments. 
     75                # ValueError if int() fails. 
     76                self._hits = len(self.query_set) 
    7977        return self._hits 
    8078 
    8179    def _get_pages(self): 
    8280        if self._pages is None: 
    83             self._pages = int(ceil(self.hits / float(self.num_per_page))) 
     81            hits = (self.hits - 1 - self.orphan) 
     82            if hits < 1: 
     83                hits = 0 
     84            self._pages = hits // self.num_per_page + 1 
    8485        return self._pages 
    8586 
    8687    hits = property(_get_hits)