forum/models/base.py

   1 import datetime
   2 import re
   3 from urllib import quote_plus, urlencode
   4 from django.db import models, IntegrityError, connection, transaction
   5 from django.utils.http import urlquote  as django_urlquote
   6 from django.utils.html import strip_tags
   7 from django.core.urlresolvers import reverse
   8 from django.contrib.contenttypes import generic
   9 from django.contrib.contenttypes.models import ContentType
  10 from django.core.cache import cache
  11 from django.template.defaultfilters import slugify
  12 from django.db.models.signals import post_delete, post_save, pre_save, pre_delete
  13 from django.utils.translation import ugettext as _
  14 from django.utils.safestring import mark_safe
  15 from django.contrib.sitemaps import ping_google
  16 import django.dispatch
  17 from forum import settings
  18 import logging
  19
  20
  21 class LazyQueryList(object):
  22     def __init__(self, model, items):
  23         self.model = model
  24         self.items = items
  25
  26     def __getitem__(self, k):
  27         return self.model.objects.get(id=self.items[k])
  28
  29     def __iter__(self):
  30         for id in self.items:
  31             yield self.model.objects.get(id=id)
  32
  33     def __len__(self):
  34         return len(self.items)
  35
  36 class CachedQuerySet(models.query.QuerySet):
  37     def lazy(self):
  38         if len(self.query.extra) == 0:
  39             return LazyQueryList(self.model, list(self.values_list('id', flat=True)))
  40         else:
  41             return self
  42
  43     def obj_from_datadict(self, datadict):
  44         obj = self.model()
  45         obj.__dict__.update(datadict)
  46         return obj
  47
  48     def get(self, *args, **kwargs):
  49         key = self.model.infer_cache_key(kwargs)
  50
  51         if key is not None:
  52             obj = cache.get(key)
  53
  54             if obj is None:
  55                 obj = super(CachedQuerySet, self).get(*args, **kwargs)
  56                 obj.cache()
  57             else:
  58                 obj = self.obj_from_datadict(obj)
  59                 obj.reset_original_state()
  60
  61             return obj
  62
  63         return super(CachedQuerySet, self).get(*args, **kwargs)
  64
  65 class CachedManager(models.Manager):
  66     use_for_related_fields = True
  67
  68     def get_query_set(self):
  69         return CachedQuerySet(self.model)
  70
  71     def get_or_create(self, *args, **kwargs):
  72         try:
  73             return self.get(*args, **kwargs)
  74         except:
  75             return super(CachedManager, self).get_or_create(*args, **kwargs)
  76
  77
  78 class DenormalizedField(object):
  79     def __init__(self, manager, *args, **kwargs):
  80         self.manager = manager
  81         self.filter = (args, kwargs)
  82
  83     def setup_class(self, cls, name):
  84         dict_name = '_%s_dencache_' % name
  85
  86         def getter(inst):
  87             val = inst.__dict__.get(dict_name, None)
  88
  89             if val is None:
  90                 val = getattr(inst, self.manager).filter(*self.filter[0], **self.filter[1]).count()
  91                 inst.__dict__[dict_name] = val
  92                 inst.cache()
  93
  94             return val
  95
  96         def reset_cache(inst):
  97             inst.__dict__.pop(dict_name, None)
  98             inst.uncache()
  99
 100         cls.add_to_class(name, property(getter))
 101         cls.add_to_class("reset_%s_cache" % name, reset_cache)
 102
 103
 104 class BaseMetaClass(models.Model.__metaclass__):
 105     to_denormalize = []
 106
 107     def __new__(cls, *args, **kwargs):
 108         new_cls = super(BaseMetaClass, cls).__new__(cls, *args, **kwargs)
 109
 110         BaseMetaClass.to_denormalize.extend(
 111             [(new_cls, name, field) for name, field in new_cls.__dict__.items() if isinstance(field, DenormalizedField)]
 112         )
 113
 114         return new_cls
 115
 116     @classmethod
 117     def setup_denormalizes(cls):
 118         for new_cls, name, field in BaseMetaClass.to_denormalize:
 119             field.setup_class(new_cls, name)
 120
 121
 122 class BaseModel(models.Model):
 123     __metaclass__ = BaseMetaClass
 124
 125     objects = CachedManager()
 126
 127     class Meta:
 128         abstract = True
 129         app_label = 'forum'
 130
 131     def __init__(self, *args, **kwargs):
 132         super(BaseModel, self).__init__(*args, **kwargs)
 133         self.reset_original_state(kwargs.keys())
 134
 135     def reset_original_state(self, reset_fields=None):
 136         self._original_state = self._as_dict()
 137
 138         if reset_fields:
 139             self._original_state.update(dict([(f, None) for f in reset_fields]))
 140
 141     def get_dirty_fields(self):
 142         return [f.name for f in self._meta.fields if self._original_state[f.attname] != self.__dict__[f.attname]]
 143
 144     def _as_dict(self):
 145         return dict([(name, getattr(self, name)) for name in
 146                      ([f.attname for f in self._meta.fields] + [k for k in self.__dict__.keys() if k.endswith('_dencache_')])
 147         ])
 148
 149     def _get_update_kwargs(self):
 150         return dict([
 151             (f.name, getattr(self, f.name)) for f in self._meta.fields if self._original_state[f.attname] != self.__dict__[f.attname]
 152         ])
 153
 154     def save(self, *args, **kwargs):
 155         put_back = [k for k, v in self.__dict__.items() if isinstance(v, models.expressions.ExpressionNode)]
 156
 157         if self.id:
 158             self.__class__.objects.filter(id=self.id).update(**self._get_update_kwargs())
 159         else:
 160             super(BaseModel, self).save()
 161
 162         if put_back:
 163             try:
 164                 self.__dict__.update(
 165                     self.__class__.objects.filter(id=self.id).values(*put_back)[0]
 166                 )
 167             except:
 168                 logging.error("Unable to read %s from %s" % (", ".join(put_back), self.__class__.__name__))
 169                 self.uncache()
 170
 171         self.reset_original_state()
 172         self.cache()
 173
 174     @classmethod
 175     def _generate_cache_key(cls, key, group=None):
 176         if group is None:
 177             group = cls.__name__
 178
 179         return '%s:%s:%s' % (settings.APP_URL, group, key)
 180
 181     def cache_key(self):
 182         return self._generate_cache_key(self.id)
 183
 184     @classmethod
 185     def infer_cache_key(cls, querydict):
 186         try:
 187             pk = [v for (k,v) in querydict.items() if k in ('pk', 'pk__exact', 'id', 'id__exact'
 188                             ) or k.endswith('_ptr__pk') or k.endswith('_ptr__id')][0]
 189
 190             return cls._generate_cache_key(pk)
 191         except:
 192             return None
 193
 194     def cache(self):
 195         cache.set(self.cache_key(), self._as_dict(), 60 * 60)
 196
 197     def uncache(self):
 198         cache.delete(self.cache_key())
 199
 200     def delete(self):
 201         self.uncache()
 202         super(BaseModel, self).delete()
 203
 204
 205 from user import User
 206 from node import Node, NodeRevision, NodeManager
 207 from action import Action
 208
 209
 210
 211
 212