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