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         if isinstance(self.order_by, (list, tuple)):
  19             return objects.order_by(*self.order_by)
  20         else:
  21             return objects.order_by(self.order_by)
  22
  23 class DummySort(object):
  24     def __init__(self, label, description=''):
  25         self.label = label
  26         self.description = description
  27
  28     def apply(self, objects):
  29         return objects
  30
  31
  32 class PaginatorContext(object):
  33     visible_page_range = 5
  34     outside_page_range = 1
  35
  36     base_path = None
  37
  38     def __init__(self, id, sort_methods=None, default_sort=None, force_sort = None, sticky_sort=False,
  39                  pagesizes=None, default_pagesize=None, prefix=''):
  40         self.id = id
  41         if sort_methods:
  42             self.has_sort = True
  43             self.sort_methods = SortedDict(data=sort_methods)
  44
  45             if not default_sort:
  46                 default_sort = sort_methods[0][0]
  47
  48             self.default_sort = default_sort
  49         else:
  50             self.has_sort = False
  51
  52
  53         if pagesizes:
  54             self.has_pagesize = True
  55             self.pagesizes = pagesizes
  56
  57             if not default_pagesize:
  58                 self.default_pagesize = pagesizes[int(math.ceil(float(len(pagesizes)) / 2)) - 1]
  59             else:
  60                 self.default_pagesize = default_pagesize
  61         else:
  62             self.has_pagesize = False
  63
  64         self.force_sort = force_sort
  65         self.sticky_sort = sticky_sort
  66         self.prefix = prefix
  67
  68     def session_preferences(self, request):
  69         return request.session.get('paginator_%s%s' % (self.prefix, self.id), {})
  70
  71     def pagesize(self, request, session_prefs=None):
  72         if not session_prefs:
  73             session_prefs = self.session_preferences(request)
  74
  75
  76         if self.has_pagesize:
  77             if request.GET.get(self.PAGESIZE, None):
  78                 try:
  79                     pagesize = int(request.GET[self.PAGESIZE])
  80                 except ValueError:
  81                     logging.error('Found invalid page size "%s", loading %s, refered by %s' % (
  82                         request.GET.get(self.PAGESIZE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
  83                     ))
  84                     raise Http404()
  85
  86                 session_prefs[self.PAGESIZE] = pagesize
  87             else:
  88                 pagesize = session_prefs.get(self.PAGESIZE, self.default_pagesize)
  89
  90             if not pagesize in self.pagesizes:
  91                 pagesize = self.default_pagesize
  92         else:
  93             pagesize = 30
  94
  95         return pagesize
  96
  97     def page(self, request):
  98         try:
  99             return int(request.GET.get(self.PAGE, 1))
 100         except ValueError:
 101             logging.error('Found invalid page number "%s", loading %s, refered by %s' % (
 102                 request.GET.get(self.PAGE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
 103             ))
 104             raise Http404()
 105
 106     def sort(self, request, session_prefs=None):
 107         if not session_prefs:
 108             session_prefs = self.session_preferences(request)
 109
 110         sort = None
 111         if self.has_sort:
 112             if request.GET.get(self.SORT, None):
 113                 sort = request.GET[self.SORT]
 114                 if self.sticky_sort or session_prefs.get('sticky_sort', False):
 115                     session_prefs[self.SORT] = sort
 116             else:
 117                 sort = self.force_sort or session_prefs.get(self.SORT, self.default_sort)
 118
 119             if not sort in self.sort_methods:
 120                 sort = self.default_sort
 121
 122         return sort
 123
 124     def sorted(self, objects, request, session_prefs=None):
 125         sort = self.sort(request, session_prefs)
 126
 127         if sort:
 128             objects = self.sort_methods[sort].apply(objects)
 129
 130         return sort, objects
 131
 132     @property
 133     def PAGESIZE(self):
 134         return self.prefix and "%s_%s" % (self.prefix, _('pagesize')) or _('pagesize')
 135
 136     @property
 137     def PAGE(self):
 138         return self.prefix and "%s_%s" % (self.prefix, _('page')) or _('page')
 139
 140     @property
 141     def SORT(self):
 142         return self.prefix and "%s_%s" % (self.prefix, _('sort')) or _('sort')
 143
 144 page_numbers_template = template.loader.get_template('paginator/page_numbers.html')
 145 page_sizes_template = template.loader.get_template('paginator/page_sizes.html')
 146 sort_tabs_template = template.loader.get_template('paginator/sort_tabs.html')
 147
 148 def paginated(request, paginators, tpl_context):
 149     if len(paginators) == 2 and isinstance(paginators[0], basestring):
 150         paginators = (paginators,)
 151
 152     for list_name, context in paginators:
 153         tpl_context[list_name] = _paginated(request, tpl_context[list_name], context)
 154
 155     return tpl_context
 156
 157 def _paginated(request, objects, context):
 158     session_prefs = context.session_preferences(request)
 159
 160     pagesize = context.pagesize(request, session_prefs)
 161     page = context.page(request)
 162     sort, objects = context.sorted(objects, request, session_prefs)
 163
 164     paginator = Paginator(objects, pagesize)
 165
 166     try:
 167         page_obj = paginator.page(page)
 168     except EmptyPage:
 169         logging.error('Found invalid page number "%s", loading %s, refered by %s' % (
 170             request.GET.get(context.PAGE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
 171         ))
 172         raise Http404()
 173
 174     if context.base_path:
 175         base_path = context.base_path
 176     else:
 177         base_path = request.path
 178         get_params = ["%s=%s" % (k, v) for k, v in request.GET.items() if not k in (context.PAGE, context.PAGESIZE, context.SORT)]
 179
 180         if get_params:
 181             base_path += "?" + "&".join(get_params)
 182
 183     url_joiner = "?" in base_path and "&" or "?"
 184
 185
 186     def get_page():
 187         object_list = page_obj.object_list
 188
 189         if hasattr(object_list, 'lazy'):
 190             return object_list.lazy()
 191         return object_list
 192     paginator.page = get_page()
 193
 194     total_pages = paginator.num_pages
 195
 196     if total_pages > 1:
 197         def page_nums():
 198             total_pages = paginator.num_pages
 199
 200             has_previous = page > 1
 201             has_next = page < total_pages
 202
 203             range_start = page - context.visible_page_range / 2
 204             range_end = page + context.visible_page_range / 2
 205
 206             if range_start < 1:
 207                 range_end = context.visible_page_range
 208                 range_start = 1
 209
 210             if range_end > total_pages:
 211                 range_start = total_pages - context.visible_page_range + 1
 212                 range_end = total_pages
 213                 if range_start < 1:
 214                     range_start = 1
 215
 216             page_numbers = []
 217
 218             if sort:
 219                 url_builder = lambda n: mark_safe("%s%s%s=%s&%s=%s" % (base_path, url_joiner, context.SORT, sort, context.PAGE, n))
 220             else:
 221                 url_builder = lambda n: mark_safe("%s%s%s=%s" % (base_path, url_joiner, context.PAGE, n))
 222
 223             if range_start > (context.outside_page_range + 1):
 224                 page_numbers.append([(n, url_builder(n)) for n in range(1, context.outside_page_range + 1)])
 225                 page_numbers.append(None)
 226             elif range_start > 1:
 227                 page_numbers.append([(n, url_builder(n)) for n in range(1, range_start)])
 228
 229             page_numbers.append([(n, url_builder(n)) for n in range(range_start, range_end + 1)])
 230
 231             if range_end < (total_pages - context.outside_page_range):
 232                 page_numbers.append(None)
 233                 page_numbers.append([(n, url_builder(n)) for n in range(total_pages - context.outside_page_range + 1, total_pages + 1)])
 234             elif range_end < total_pages:
 235                 page_numbers.append([(n, url_builder(n)) for n in range(range_end + 1, total_pages + 1)])
 236
 237             return page_numbers_template.render(template.Context({
 238                 'has_previous': has_previous,
 239                 'previous_url': has_previous and url_builder(page - 1) or None,
 240                 'has_next': has_next,
 241                 'next_url': has_next and url_builder(page + 1) or None,
 242                 'current': page,
 243                 'page_numbers': page_numbers
 244             }))
 245         paginator.page_numbers = page_nums
 246     else:
 247         paginator.page_numbers = ''
 248
 249     if pagesize:
 250         def page_sizes():
 251             if sort:
 252                 url_builder = lambda s: mark_safe("%s%s%s=%s&%s=%s" % (base_path, url_joiner, context.SORT, sort, context.PAGESIZE, s))
 253             else:
 254                 url_builder = lambda s: mark_safe("%s%s%s=%s" % (base_path, url_joiner, context.PAGESIZE, s))
 255
 256             sizes = [(s, url_builder(s)) for s in context.pagesizes]
 257
 258             return page_sizes_template.render(template.Context({
 259                 'current': pagesize,
 260                 'sizes': sizes
 261             }))
 262
 263         paginator.page_sizes = page_sizes
 264     else:
 265         paginator.page_sizes = ''
 266
 267     if sort:
 268         def sort_tabs():
 269             url_builder = lambda s: mark_safe("%s%s%s=%s" % (base_path, url_joiner, context.SORT, s))
 270             sorts = [(n, s.label, url_builder(n), s.description) for n, s in context.sort_methods.items()]
 271
 272             return sort_tabs_template.render(template.Context({
 273                 'current': sort,
 274                 'sorts': sorts,
 275                 'sticky': session_prefs.get('sticky_sort', False)
 276             }))
 277         paginator.sort_tabs = sort_tabs()
 278     else:
 279         paginator.sort_tabs = ''
 280
 281     request.session['paginator_%s' % context.id] = session_prefs
 282     objects.paginator = paginator
 283     return objects