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.http import urlquote
   8 from django.utils.safestring import mark_safe
   9 from django.utils.html import strip_tags
  10
  11 import logging
  12
  13 def generate_uri(querydict, exclude=None):
  14     all = []
  15
  16     for k, l in querydict.iterlists():
  17         if (not exclude) or (not k in exclude):
  18             all += ["%s=%s" % (k, urlquote(v)) for v in l]
  19
  20     return "&".join(all)
  21
  22 class SortBase(object):
  23     def __init__(self, label, description=''):
  24         self.label = label
  25         self.description = description
  26
  27 class SimpleSort(SortBase):
  28     def __init__(self, label, order_by, description=''):
  29         super(SimpleSort, self) .__init__(label, description)
  30         self.order_by = order_by
  31
  32     def _get_order_by(self):
  33         return isinstance(self.order_by, (list, tuple)) and self.order_by or [self.order_by]
  34
  35     def apply(self, objects):
  36         return objects.order_by(*self._get_order_by())
  37
  38 class PaginatorContext(object):
  39     visible_page_range = 5
  40     outside_page_range = 1
  41
  42     base_path = None
  43
  44     def __init__(self, id, sort_methods=None, default_sort=None, force_sort = None,
  45                  pagesizes=None, default_pagesize=None, prefix=''):
  46         self.id = id
  47         if sort_methods:
  48             self.has_sort = True
  49             self.sort_methods = SortedDict(data=sort_methods)
  50
  51             if not default_sort:
  52                 default_sort = sort_methods[0][0]
  53
  54             self.default_sort = default_sort
  55         else:
  56             self.has_sort = False
  57
  58
  59         if pagesizes:
  60             self.has_pagesize = True
  61             self.pagesizes = pagesizes
  62
  63             if not default_pagesize:
  64                 self.default_pagesize = pagesizes[int(math.ceil(float(len(pagesizes)) / 2)) - 1]
  65             else:
  66                 self.default_pagesize = default_pagesize
  67         else:
  68             self.has_pagesize = False
  69
  70         self.force_sort = force_sort
  71         self.prefix = prefix
  72
  73     def preferences(self, request):
  74         if request.user.is_authenticated():
  75             if request.user.prop.pagination:
  76                 preferences = request.user.prop.pagination.get(self.id, {})
  77             else:
  78                 preferences = {}
  79         else:
  80             preferences = request.session.get('paginator_%s%s' % (self.prefix, self.id), {})
  81
  82         return preferences
  83
  84     def set_preferences(self, request, preferences):
  85         if request.user.is_authenticated():
  86             all_preferences = request.user.prop.pagination or {}
  87             all_preferences[self.id] = preferences
  88             request.user.prop.pagination = all_preferences
  89         else:
  90             request.session['paginator_%s%s' % (self.prefix, self.id)] = preferences
  91
  92     def pagesize(self, request, session_prefs=None):
  93         if not session_prefs:
  94             session_prefs = self.preferences(request)
  95
  96
  97         if self.has_pagesize:
  98             if request.GET.get(self.PAGESIZE, None):
  99                 try:
 100                     pagesize = int(request.GET[self.PAGESIZE])
 101                 except ValueError:
 102                     logging.error('Found invalid page size "%s", loading %s, refered by %s' % (
 103                         request.GET.get(self.PAGESIZE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
 104                     ))
 105                     raise Http404()
 106
 107                 session_prefs[self.PAGESIZE] = pagesize
 108             else:
 109                 pagesize = session_prefs.get(self.PAGESIZE, self.default_pagesize)
 110
 111             if not pagesize in self.pagesizes:
 112                 pagesize = self.default_pagesize
 113         else:
 114             pagesize = 30
 115
 116         return pagesize
 117
 118     def page(self, request):
 119         try:
 120             return int(request.GET.get(self.PAGE, "1").strip())
 121         except ValueError:
 122             logging.error('Found invalid page number "%s", loading %s, refered by %s' % (
 123                 request.GET.get(self.PAGE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
 124             ))
 125             raise Http404()
 126
 127     def sort(self, request, session_prefs=None):
 128         if not session_prefs:
 129             session_prefs = self.preferences(request)
 130
 131         sort = None
 132         sticky = request.user.is_authenticated() and request.user.prop.preferences and request.user.prop.preferences.get('sticky_sorts', False)
 133
 134         if self.has_sort:
 135             if request.GET.get(self.SORT, None):
 136                 sort = request.GET[self.SORT]
 137
 138                 if sticky:
 139                     session_prefs[self.SORT] = sort
 140             else:
 141                 sort = self.force_sort or (sticky and session_prefs.get(self.SORT, None)) or self.default_sort
 142
 143             if not sort in self.sort_methods:
 144                 sort = self.default_sort
 145
 146         return sort
 147
 148     def sorted(self, objects, request, session_prefs=None):
 149         sort = self.sort(request, session_prefs)
 150
 151         if sort:
 152             objects = self.sort_methods[sort].apply(objects)
 153
 154         return sort, objects
 155
 156     @property
 157     def PAGESIZE(self):
 158         return self.prefix and "%s_%s" % (self.prefix, _('pagesize')) or _('pagesize')
 159
 160     @property
 161     def PAGE(self):
 162         return self.prefix and "%s_%s" % (self.prefix, _('page')) or _('page')
 163
 164     @property
 165     def SORT(self):
 166         return self.prefix and "%s_%s" % (self.prefix, _('sort')) or _('sort')
 167
 168 page_numbers_template = template.loader.get_template('paginator/page_numbers.html')
 169 page_sizes_template = template.loader.get_template('paginator/page_sizes.html')
 170 sort_tabs_template = template.loader.get_template('paginator/sort_tabs.html')
 171
 172 def paginated(request, paginators, tpl_context):
 173     if len(paginators) == 2 and isinstance(paginators[0], basestring):
 174         paginators = (paginators,)
 175
 176     for list_name, context in paginators:
 177         tpl_context[list_name] = _paginated(request, tpl_context[list_name], context)
 178
 179     return tpl_context
 180
 181 def _paginated(request, objects, context):
 182     session_prefs = context.preferences(request)
 183
 184     pagesize = context.pagesize(request, session_prefs)
 185     page = context.page(request)
 186     sort, objects = context.sorted(objects, request, session_prefs)
 187
 188     paginator = Paginator(objects, pagesize)
 189
 190     try:
 191         page_obj = paginator.page(page)
 192     except EmptyPage:
 193         logging.error('Found invalid page number "%s", loading %s, refered by %s' % (
 194             request.GET.get(context.PAGE, ''), request.path, request.META.get('HTTP_REFERER', 'UNKNOWN')
 195         ))
 196         raise Http404()
 197
 198     if context.base_path:
 199         base_path = context.base_path
 200     else:
 201         base_path = request.path
 202         get_params = generate_uri(request.GET, (context.PAGE, context.PAGESIZE, context.SORT))
 203
 204         if get_params:
 205             base_path += "?" + get_params
 206
 207     url_joiner = "?" in base_path and "&" or "?"
 208
 209
 210     def get_page():
 211         object_list = page_obj.object_list
 212
 213         if hasattr(object_list, 'lazy'):
 214             return object_list.lazy()
 215         return object_list
 216     paginator.page = get_page()
 217
 218     total_pages = paginator.num_pages
 219
 220     if total_pages > 1:
 221         def page_nums():
 222             total_pages = paginator.num_pages
 223
 224             has_previous = page > 1
 225             has_next = page < total_pages
 226
 227             range_start = page - context.visible_page_range / 2
 228             range_end = page + context.visible_page_range / 2
 229
 230             if range_start < 1:
 231                 range_end = context.visible_page_range
 232                 range_start = 1
 233
 234             if range_end > total_pages:
 235                 range_start = total_pages - context.visible_page_range + 1
 236                 range_end = total_pages
 237                 if range_start < 1:
 238                     range_start = 1
 239
 240             page_numbers = []
 241
 242             if sort:
 243                 url_builder = lambda n: mark_safe("%s%s%s=%s&%s=%s" % (base_path, url_joiner, context.SORT, sort, context.PAGE, n))
 244             else:
 245                 url_builder = lambda n: mark_safe("%s%s%s=%s" % (base_path, url_joiner, context.PAGE, n))
 246
 247             if range_start > (context.outside_page_range + 1):
 248                 page_numbers.append([(n, url_builder(n)) for n in range(1, context.outside_page_range + 1)])
 249                 page_numbers.append(None)
 250             elif range_start > 1:
 251                 page_numbers.append([(n, url_builder(n)) for n in range(1, range_start)])
 252
 253             page_numbers.append([(n, url_builder(n)) for n in range(range_start, range_end + 1)])
 254
 255             if range_end < (total_pages - context.outside_page_range):
 256                 page_numbers.append(None)
 257                 page_numbers.append([(n, url_builder(n)) for n in range(total_pages - context.outside_page_range + 1, total_pages + 1)])
 258             elif range_end < total_pages:
 259                 page_numbers.append([(n, url_builder(n)) for n in range(range_end + 1, total_pages + 1)])
 260
 261             return page_numbers_template.render(template.Context({
 262                 'has_previous': has_previous,
 263                 'previous_url': has_previous and url_builder(page - 1) or None,
 264                 'has_next': has_next,
 265                 'next_url': has_next and url_builder(page + 1) or None,
 266                 'current': page,
 267                 'page_numbers': page_numbers
 268             }))
 269         paginator.page_numbers = page_nums
 270     else:
 271         paginator.page_numbers = ''
 272
 273     if pagesize:
 274         def page_sizes():
 275             if sort:
 276                 url_builder = lambda s: mark_safe("%s%s%s=%s&%s=%s" % (base_path, url_joiner, context.SORT, sort, context.PAGESIZE, s))
 277             else:
 278                 url_builder = lambda s: mark_safe("%s%s%s=%s" % (base_path, url_joiner, context.PAGESIZE, s))
 279
 280             sizes = [(s, url_builder(s)) for s in context.pagesizes]
 281
 282             return page_sizes_template.render(template.Context({
 283                 'current': pagesize,
 284                 'sizes': sizes
 285             }))
 286
 287         paginator.page_sizes = page_sizes
 288     else:
 289         paginator.page_sizes = ''
 290
 291     if sort:
 292         def sort_tabs():
 293             url_builder = lambda s: mark_safe("%s%s%s=%s" % (base_path, url_joiner, context.SORT, s))
 294             sorts = [(n, s.label, url_builder(n), strip_tags(s.description)) for n, s in context.sort_methods.items()]
 295
 296             for name, label, url, descr in sorts:
 297                 paginator.__dict__['%s_sort_link' % name] = url
 298
 299             return sort_tabs_template.render(template.Context({
 300                 'current': sort,
 301                 'sorts': sorts,
 302                 'sticky': session_prefs.get('sticky_sort', False)
 303             }))
 304         paginator.sort_tabs = sort_tabs()
 305         paginator.sort_description = mark_safe(context.sort_methods[sort].description)
 306         paginator.current_sort = sort
 307     else:
 308         paginator.sort_tabs = paginator.sort_description = ''
 309         paginator.current_sort = ''
 310
 311     context.set_preferences(request, session_prefs)
 312     objects.paginator = paginator
 313     return objects