forum/utils/pagination.py

   1 import math
   2 from django.utils.datastructures import SortedDict
   3 from django import template
   4 from django.core.paginator import Paginator, EmptyPage
   5 from django.utils.translation import ugettext as _
   6 from django.http import Http404
   7 from django.utils.safestring import mark_safe
   8 from django.utils.http import urlquote
   9 import logging
  10
  11 class SimpleSort(object):
  12     def __init__(self, label, order_by, description=''):
  13         self.label = label
  14         self.description = description
  15         self.order_by = order_by
  16
  17     def apply(self, objects):
  18         return objects.order_by(self.order_by)
  19
  20
  21 class PaginatorContext(object):
  22     visible_page_range = 5
  23     outside_page_range = 1
  24
  25     base_path = None
  26
  27     def __init__(self, id, sort_methods=None, default_sort=None, pagesizes=None, default_pagesize=None):
  28         self.id = id
  29         if sort_methods:
  30             self.has_sort = True
  31             self.sort_methods = SortedDict(data=sort_methods)
  32
  33             if not default_sort:
  34                 default_sort = sort_methods[0][0]
  35
  36             self.default_sort = default_sort
  37         else:
  38             self.has_sort = False
  39
  40
  41         if pagesizes:
  42             self.has_pagesize = True
  43             self.pagesizes = pagesizes
  44
  45             if not default_pagesize:
  46                 self.default_pagesize = pagesizes[int(math.ceil(float(len(pagesizes)) / 2)) - 1]
  47             else:
  48                 self.default_pagesize = default_pagesize
  49         else:
  50             self.has_pagesize = False
  51
  52
  53
  54 class labels(object):
  55     PAGESIZE = _('pagesize')
  56     PAGE = _('page')
  57     SORT = _('sort')
  58
  59 page_numbers_template = template.loader.get_template('paginator/page_numbers.html')
  60 page_sizes_template = template.loader.get_template('paginator/page_sizes.html')
  61 sort_tabs_template = template.loader.get_template('paginator/sort_tabs.html')
  62
  63 def paginated(request, list_name, context, tpl_context):
  64     session_prefs = request.session.get('paginator_%s' % context.id, {})
  65     objects = tpl_context[list_name]
  66
  67     if context.has_pagesize:
  68         if request.GET.get(labels.PAGESIZE, None):
  69             try:
  70                 pagesize = int(request.GET[labels.PAGESIZE])
  71             except ValueError:
  72                 logging.error('Found invalid page size "%s", loading %s, refered by %s' % (
  73                     request.GET.get(labels.PAGESIZE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
  74                 ))
  75                 raise Http404()
  76
  77             session_prefs[labels.PAGESIZE] = pagesize
  78         else:
  79             pagesize = session_prefs.get(labels.PAGESIZE, context.default_pagesize)
  80
  81         if not pagesize in context.pagesizes:
  82             pagesize = context.default_pagesize
  83     else:
  84         pagesize = 30
  85
  86
  87
  88
  89
  90     try:
  91         page = int(request.GET.get(labels.PAGE, 1))
  92     except ValueError:
  93         logging.error('Found invalid page number "%s", loading %s, refered by %s' % (
  94             request.GET.get(labels.PAGE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
  95         ))
  96         raise Http404()
  97
  98     sort = None
  99     if context.has_sort:
 100         if request.GET.get(labels.SORT, None):
 101             sort = request.GET[labels.SORT]
 102             if session_prefs.get('sticky_sort', False):
 103                 session_prefs[labels.SORT] = sort
 104         else:
 105             sort = session_prefs.get(labels.SORT, context.default_sort)
 106
 107         if not sort in context.sort_methods:
 108             sort = context.default_sort
 109
 110         objects = context.sort_methods[sort].apply(objects)
 111
 112     paginator = Paginator(objects, pagesize)
 113
 114     try:
 115         page_obj = paginator.page(page)
 116     except EmptyPage:
 117         logging.error('Found invalid page number "%s", loading %s, refered by %s' % (
 118             request.GET.get(labels.PAGE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
 119         ))
 120         raise Http404()
 121
 122     if context.base_path:
 123         base_path = context.base_path
 124     else:
 125         base_path = request.path
 126         get_params = ["%s=%s" % (k, v) for k, v in request.GET.items() if not k in (labels.PAGE, labels.PAGESIZE, labels.SORT)]
 127
 128         if get_params:
 129             base_path += "?" + "&".join(get_params)
 130
 131     url_joiner = "?" in base_path and "&" or "?"
 132
 133
 134     def get_page():
 135         object_list = page_obj.object_list
 136
 137         if hasattr(object_list, 'lazy'):
 138             return object_list.lazy()
 139         return page_obj.object_list
 140     objects.page = get_page
 141
 142     total_pages = paginator.num_pages
 143
 144     if total_pages > 1:
 145         def page_nums():
 146             total_pages = paginator.num_pages
 147
 148             has_previous = page > 1
 149             has_next = page < total_pages
 150
 151             range_start = page - context.visible_page_range / 2
 152             range_end = page + context.visible_page_range / 2
 153
 154             if range_start < 1:
 155                 range_end = context.visible_page_range
 156                 range_start = 1
 157
 158             if range_end > total_pages:
 159                 range_start = total_pages - context.visible_page_range + 1
 160                 range_end = total_pages
 161                 if range_start < 1:
 162                     range_start = 1
 163
 164             page_numbers = []
 165
 166             if sort:
 167                 url_builder = lambda n: mark_safe("%s%s%s=%s&%s=%s" % (base_path, url_joiner, labels.SORT, sort, labels.PAGE, n))
 168             else:
 169                 url_builder = lambda n: mark_safe("%s%s%s=%s" % (base_path, url_joiner, labels.PAGE, n))
 170
 171             if range_start > (context.outside_page_range + 1):
 172                 page_numbers.append([(n, url_builder(n)) for n in range(1, context.outside_page_range + 1)])
 173                 page_numbers.append(None)
 174             elif range_start > 1:
 175                 page_numbers.append([(n, url_builder(n)) for n in range(1, range_start)])
 176
 177             page_numbers.append([(n, url_builder(n)) for n in range(range_start, range_end + 1)])
 178
 179             if range_end < (total_pages - context.outside_page_range):
 180                 page_numbers.append(None)
 181                 page_numbers.append([(n, url_builder(n)) for n in range(total_pages - context.outside_page_range + 1, total_pages + 1)])
 182             elif range_end < total_pages:
 183                 page_numbers.append([(n, url_builder(n)) for n in range(range_end + 1, total_pages + 1)])
 184
 185             return page_numbers_template.render(template.Context({
 186                 'has_previous': has_previous,
 187                 'previous_url': has_previous and url_builder(page - 1) or None,
 188                 'has_next': has_next,
 189                 'next_url': has_next and url_builder(page + 1) or None,
 190                 'current': page,
 191                 'page_numbers': page_numbers
 192             }))
 193         objects.page_numbers = page_nums
 194     else:
 195         objects.page_numbers = ''
 196
 197     if pagesize:
 198         def page_sizes():
 199             if sort:
 200                 url_builder = lambda s: mark_safe("%s%s%s=%s&%s=%s" % (base_path, url_joiner, labels.SORT, sort, labels.PAGESIZE, s))
 201             else:
 202                 url_builder = lambda s: mark_safe("%s%s%s=%s" % (base_path, url_joiner, labels.PAGESIZE, s))
 203
 204             sizes = [(s, url_builder(s)) for s in context.pagesizes]
 205
 206             return page_sizes_template.render(template.Context({
 207                 'current': pagesize,
 208                 'sizes': sizes
 209             }))
 210
 211         objects.page_sizes = page_sizes
 212     else:
 213         objects.page_sizes = ''
 214
 215     if sort:
 216         def sort_tabs():
 217             url_builder = lambda s: mark_safe("%s%s%s=%s" % (base_path, url_joiner, labels.SORT, s))
 218             sorts = [(n, s.label, url_builder(n), s.description) for n, s in context.sort_methods.items()]
 219
 220             return sort_tabs_template.render(template.Context({
 221                 'current': sort,
 222                 'sorts': sorts,
 223                 'sticky': session_prefs.get('sticky_sort', False)
 224             }))
 225         objects.sort_tabs = sort_tabs()
 226     else:
 227         objects.sort_tabs = ''
 228
 229     request.session['paginator_%s' % context.id] = session_prefs
 230     tpl_context[list_name] = objects
 231     return tpl_context