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,
  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.prefix = prefix
  66
  67     def preferences(self, request):
  68         if request.user.is_authenticated():
  69             if request.user.prop.pagination:
  70                 preferences = request.user.prop.pagination.get(self.id, {})
  71             else:
  72                 preferences = {}
  73         else:
  74             preferences = request.session.get('paginator_%s%s' % (self.prefix, self.id), {})
  75
  76         return preferences
  77
  78     def set_preferences(self, request, preferences):
  79         if request.user.is_authenticated():
  80             all_preferences = request.user.prop.pagination or {}
  81             all_preferences[self.id] = preferences
  82             request.user.prop.pagination = all_preferences
  83         else:
  84             request.session['paginator_%s%s' % (self.prefix, self.id)] = preferences
  85
  86     def pagesize(self, request, session_prefs=None):
  87         if not session_prefs:
  88             session_prefs = self.preferences(request)
  89
  90
  91         if self.has_pagesize:
  92             if request.GET.get(self.PAGESIZE, None):
  93                 try:
  94                     pagesize = int(request.GET[self.PAGESIZE])
  95                 except ValueError:
  96                     logging.error('Found invalid page size "%s", loading %s, refered by %s' % (
  97                         request.GET.get(self.PAGESIZE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
  98                     ))
  99                     raise Http404()
 100
 101                 session_prefs[self.PAGESIZE] = pagesize
 102             else:
 103                 pagesize = session_prefs.get(self.PAGESIZE, self.default_pagesize)
 104
 105             if not pagesize in self.pagesizes:
 106                 pagesize = self.default_pagesize
 107         else:
 108             pagesize = 30
 109
 110         return pagesize
 111
 112     def page(self, request):
 113         try:
 114             return int(request.GET.get(self.PAGE, 1))
 115         except ValueError:
 116             logging.error('Found invalid page number "%s", loading %s, refered by %s' % (
 117                 request.GET.get(self.PAGE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
 118             ))
 119             raise Http404()
 120
 121     def sort(self, request, session_prefs=None):
 122         if not session_prefs:
 123             session_prefs = self.preferences(request)
 124
 125         sort = None
 126         sticky = request.user.is_authenticated() and request.user.prop.preferences and request.user.prop.preferences.get('sticky_sorts', False)
 127
 128         if self.has_sort:
 129             if request.GET.get(self.SORT, None):
 130                 sort = request.GET[self.SORT]
 131
 132                 if sticky:
 133                     session_prefs[self.SORT] = sort
 134             else:
 135                 sort = self.force_sort or (sticky and session_prefs.get(self.SORT, None)) or self.default_sort
 136
 137             if not sort in self.sort_methods:
 138                 sort = self.default_sort
 139
 140         return sort
 141
 142     def sorted(self, objects, request, session_prefs=None):
 143         sort = self.sort(request, session_prefs)
 144
 145         if sort:
 146             objects = self.sort_methods[sort].apply(objects)
 147
 148         return sort, objects
 149
 150     @property
 151     def PAGESIZE(self):
 152         return self.prefix and "%s_%s" % (self.prefix, _('pagesize')) or _('pagesize')
 153
 154     @property
 155     def PAGE(self):
 156         return self.prefix and "%s_%s" % (self.prefix, _('page')) or _('page')
 157
 158     @property
 159     def SORT(self):
 160         return self.prefix and "%s_%s" % (self.prefix, _('sort')) or _('sort')
 161
 162 page_numbers_template = template.loader.get_template('paginator/page_numbers.html')
 163 page_sizes_template = template.loader.get_template('paginator/page_sizes.html')
 164 sort_tabs_template = template.loader.get_template('paginator/sort_tabs.html')
 165
 166 def paginated(request, paginators, tpl_context):
 167     if len(paginators) == 2 and isinstance(paginators[0], basestring):
 168         paginators = (paginators,)
 169
 170     for list_name, context in paginators:
 171         tpl_context[list_name] = _paginated(request, tpl_context[list_name], context)
 172
 173     return tpl_context
 174
 175 def _paginated(request, objects, context):
 176     session_prefs = context.preferences(request)
 177
 178     pagesize = context.pagesize(request, session_prefs)
 179     page = context.page(request)
 180     sort, objects = context.sorted(objects, request, session_prefs)
 181
 182     paginator = Paginator(objects, pagesize)
 183
 184     try:
 185         page_obj = paginator.page(page)
 186     except EmptyPage:
 187         logging.error('Found invalid page number "%s", loading %s, refered by %s' % (
 188             request.GET.get(context.PAGE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
 189         ))
 190         raise Http404()
 191
 192     if context.base_path:
 193         base_path = context.base_path
 194     else:
 195         base_path = request.path
 196         get_params = ["%s=%s" % (k, v) for k, v in request.GET.items() if not k in (context.PAGE, context.PAGESIZE, context.SORT)]
 197
 198         if get_params:
 199             base_path += "?" + "&".join(get_params)
 200
 201     url_joiner = "?" in base_path and "&" or "?"
 202
 203
 204     def get_page():
 205         object_list = page_obj.object_list
 206
 207         if hasattr(object_list, 'lazy'):
 208             return object_list.lazy()
 209         return object_list
 210     paginator.page = get_page()
 211
 212     total_pages = paginator.num_pages
 213
 214     if total_pages > 1:
 215         def page_nums():
 216             total_pages = paginator.num_pages
 217
 218             has_previous = page > 1
 219             has_next = page < total_pages
 220
 221             range_start = page - context.visible_page_range / 2
 222             range_end = page + context.visible_page_range / 2
 223
 224             if range_start < 1:
 225                 range_end = context.visible_page_range
 226                 range_start = 1
 227
 228             if range_end > total_pages:
 229                 range_start = total_pages - context.visible_page_range + 1
 230                 range_end = total_pages
 231                 if range_start < 1:
 232                     range_start = 1
 233
 234             page_numbers = []
 235
 236             if sort:
 237                 url_builder = lambda n: mark_safe("%s%s%s=%s&%s=%s" % (base_path, url_joiner, context.SORT, sort, context.PAGE, n))
 238             else:
 239                 url_builder = lambda n: mark_safe("%s%s%s=%s" % (base_path, url_joiner, context.PAGE, n))
 240
 241             if range_start > (context.outside_page_range + 1):
 242                 page_numbers.append([(n, url_builder(n)) for n in range(1, context.outside_page_range + 1)])
 243                 page_numbers.append(None)
 244             elif range_start > 1:
 245                 page_numbers.append([(n, url_builder(n)) for n in range(1, range_start)])
 246
 247             page_numbers.append([(n, url_builder(n)) for n in range(range_start, range_end + 1)])
 248
 249             if range_end < (total_pages - context.outside_page_range):
 250                 page_numbers.append(None)
 251                 page_numbers.append([(n, url_builder(n)) for n in range(total_pages - context.outside_page_range + 1, total_pages + 1)])
 252             elif range_end < total_pages:
 253                 page_numbers.append([(n, url_builder(n)) for n in range(range_end + 1, total_pages + 1)])
 254
 255             return page_numbers_template.render(template.Context({
 256                 'has_previous': has_previous,
 257                 'previous_url': has_previous and url_builder(page - 1) or None,
 258                 'has_next': has_next,
 259                 'next_url': has_next and url_builder(page + 1) or None,
 260                 'current': page,
 261                 'page_numbers': page_numbers
 262             }))
 263         paginator.page_numbers = page_nums
 264     else:
 265         paginator.page_numbers = ''
 266
 267     if pagesize:
 268         def page_sizes():
 269             if sort:
 270                 url_builder = lambda s: mark_safe("%s%s%s=%s&%s=%s" % (base_path, url_joiner, context.SORT, sort, context.PAGESIZE, s))
 271             else:
 272                 url_builder = lambda s: mark_safe("%s%s%s=%s" % (base_path, url_joiner, context.PAGESIZE, s))
 273
 274             sizes = [(s, url_builder(s)) for s in context.pagesizes]
 275
 276             return page_sizes_template.render(template.Context({
 277                 'current': pagesize,
 278                 'sizes': sizes
 279             }))
 280
 281         paginator.page_sizes = page_sizes
 282     else:
 283         paginator.page_sizes = ''
 284
 285     if sort:
 286         def sort_tabs():
 287             url_builder = lambda s: mark_safe("%s%s%s=%s" % (base_path, url_joiner, context.SORT, s))
 288             sorts = [(n, s.label, url_builder(n), s.description) for n, s in context.sort_methods.items()]
 289
 290             return sort_tabs_template.render(template.Context({
 291                 'current': sort,
 292                 'sorts': sorts,
 293                 'sticky': session_prefs.get('sticky_sort', False)
 294             }))
 295         paginator.sort_tabs = sort_tabs()
 296     else:
 297         paginator.sort_tabs = ''
 298
 299     context.set_preferences(request, session_prefs)
 300     objects.paginator = paginator
 301     return objects