import django.db.models.manipulators import django.db.models.manager from django.core import validators from django.core.exceptions import ObjectDoesNotExist from django.db.models.fields import AutoField, ImageField, FieldDoesNotExist from django.db.models.fields.related import OneToOneRel, ManyToOneRel from django.db.models.query import delete_objects from django.db.models.options import Options, AdminOptions from django.db import connection, backend, transaction from django.db.models import signals from django.db.models.loading import register_models, get_model from django.dispatch import dispatcher from django.utils.datastructures import SortedDict from django.utils.functional import curry from django.conf import settings import types import sys import os class ModelBase(type): "Metaclass for all models" def __new__(cls, name, bases, attrs): # If this isn't a subclass of Model, don't do anything special. if not bases or bases == (object,): return type.__new__(cls, name, bases, attrs) # Create the class. new_class = type.__new__(cls, name, bases, {'__module__': attrs.pop('__module__')}) new_class.add_to_class('_meta', Options(attrs.pop('Meta', None))) new_class.add_to_class('DoesNotExist', types.ClassType('DoesNotExist', (ObjectDoesNotExist,), {})) # Build complete list of parents for base in bases: # TODO: Checking for the presence of '_meta' is hackish. if '_meta' in dir(base): new_class._meta.parents.append(base) new_class._meta.parents.extend(base._meta.parents) model_module = sys.modules[new_class.__module__] if getattr(new_class._meta, 'app_label', None) is None: # Figure out the app_label by looking one level up. # For 'django.contrib.sites.models', this would be 'sites'. new_class._meta.app_label = model_module.__name__.split('.')[-2] # Bail out early if we have already created this class. m = get_model(new_class._meta.app_label, name, False) if m is not None: return m # Add all attributes to the class. for obj_name, obj in attrs.items(): new_class.add_to_class(obj_name, obj) # Add Fields inherited from parents for parent in new_class._meta.parents: for field in parent._meta.fields: # Only add parent fields if they aren't defined for this class. try: new_class._meta.get_field(field.name) except FieldDoesNotExist: field.contribute_to_class(new_class, field.name) new_class._prepare() register_models(new_class._meta.app_label, new_class) # Because of the way imports happen (recursively), we may or may not be # the first class for this model to register with the framework. There # should only be one class for each model, so we must always return the # registered version. return get_model(new_class._meta.app_label, name, False) class Model(object): __metaclass__ = ModelBase def _get_pk_val(self): return getattr(self, self._meta.pk.attname) def __repr__(self): return '<%s: %s>' % (self.__class__.__name__, self) def __str__(self): return '%s object' % self.__class__.__name__ def __eq__(self, other): return isinstance(other, self.__class__) and self._get_pk_val() == other._get_pk_val() def __ne__(self, other): return not self.__eq__(other) def __init__(self, *args, **kwargs): dispatcher.send(signal=signals.pre_init, sender=self.__class__, args=args, kwargs=kwargs) for f in self._meta.fields: if isinstance(f.rel, ManyToOneRel): try: # Assume object instance was passed in. rel_obj = kwargs.pop(f.name) except KeyError: try: # Object instance wasn't passed in -- must be an ID. val = kwargs.pop(f.attname) except KeyError: val = f.get_default() else: # Object instance was passed in. # Special case: You can pass in "None" for related objects if it's allowed. if rel_obj is None and f.null: val = None else: try: val = getattr(rel_obj, f.rel.get_related_field().attname) except AttributeError: raise TypeError, "Invalid value: %r should be a %s instance, not a %s" % (f.name, f.rel.to, type(rel_obj)) setattr(self, f.attname, val) else: val = kwargs.pop(f.attname, f.get_default()) setattr(self, f.attname, val) for prop in kwargs.keys(): try: if isinstance(getattr(self.__class__, prop), property): setattr(self, prop, kwargs.pop(prop)) except AttributeError: pass if kwargs: raise TypeError, "'%s' is an invalid keyword argument for this function" % kwargs.keys()[0] for i, arg in enumerate(args): setattr(self, self._meta.fields[i].attname, arg) dispatcher.send(signal=signals.post_init, sender=self.__class__, instance=self) def add_to_class(cls, name, value): if name == 'Admin': assert type(value) == types.ClassType, "%r attribute of %s model must be a class, not a %s object" % (name, cls.__name__, type(value)) value = AdminOptions(**dict([(k, v) for k, v in value.__dict__.items() if not k.startswith('_')])) if hasattr(value, 'contribute_to_class'): value.contribute_to_class(cls, name) else: setattr(cls, name, value) add_to_class = classmethod(add_to_class) def _prepare(cls): # Creates some methods once self._meta has been populated. opts = cls._meta opts._prepare(cls) if opts.order_with_respect_to: cls.get_next_in_order = curry(cls._get_next_or_previous_in_order, is_next=True) cls.get_previous_in_order = curry(cls._get_next_or_previous_in_order, is_next=False) setattr(opts.order_with_respect_to.rel.to, 'get_%s_order' % cls.__name__.lower(), curry(method_get_order, cls)) setattr(opts.order_with_respect_to.rel.to, 'set_%s_order' % cls.__name__.lower(), curry(method_set_order, cls)) # Give the class a docstring -- its definition. if cls.__doc__ is None: cls.__doc__ = "%s(%s)" % (cls.__name__, ", ".join([f.attname for f in opts.fields])) if hasattr(cls, 'get_absolute_url'): cls.get_absolute_url = curry(get_absolute_url, opts, cls.get_absolute_url) dispatcher.send(signal=signals.class_prepared, sender=cls) _prepare = classmethod(_prepare) def save(self): dispatcher.send(signal=signals.pre_save, sender=self.__class__, instance=self) non_pks = [f for f in self._meta.fields if not f.primary_key] cursor = connection.cursor() # First, try an UPDATE. If that doesn't update anything, do an INSERT. pk_val = self._get_pk_val() pk_set = bool(pk_val) record_exists = True if pk_set: # Determine whether a record with the primary key already exists. cursor.execute("SELECT 1 FROM %s WHERE %s=%%s LIMIT 1" % \ (backend.quote_name(self._meta.db_table), backend.quote_name(self._meta.pk.column)), [pk_val]) # If it does already exist, do an UPDATE. if cursor.fetchone(): db_values = [f.get_db_prep_save(f.pre_save(self, False)) for f in non_pks] if db_values: cursor.execute("UPDATE %s SET %s WHERE %s=%%s" % \ (backend.quote_name(self._meta.db_table), ','.join(['%s=%%s' % backend.quote_name(f.column) for f in non_pks]), backend.quote_name(self._meta.pk.column)), db_values + [pk_val]) else: record_exists = False if not pk_set or not record_exists: field_names = [backend.quote_name(f.column) for f in self._meta.fields if not isinstance(f, AutoField)] db_values = [f.get_db_prep_save(f.pre_save(self, True)) for f in self._meta.fields if not isinstance(f, AutoField)] # If the PK has been manually set, respect that. if pk_set: field_names += [f.column for f in self._meta.fields if isinstance(f, AutoField)] db_values += [f.get_db_prep_save(f.pre_save(self, True)) for f in self._meta.fields if isinstance(f, AutoField)] placeholders = ['%s'] * len(field_names) if self._meta.order_with_respect_to: field_names.append(backend.quote_name('_order')) # TODO: This assumes the database supports subqueries. placeholders.append('(SELECT COUNT(*) FROM %s WHERE %s = %%s)' % \ (backend.quote_name(self._meta.db_table), backend.quote_name(self._meta.order_with_respect_to.column))) db_values.append(getattr(self, self._meta.order_with_respect_to.attname)) if db_values: cursor.execute("INSERT INTO %s (%s) VALUES (%s)" % \ (backend.quote_name(self._meta.db_table), ','.join(field_names), ','.join(placeholders)), db_values) else: # Create a new record with defaults for everything. cursor.execute("INSERT INTO %s (%s) VALUES (%s)" % (backend.quote_name(self._meta.db_table), backend.quote_name(self._meta.pk.column), backend.get_pk_default_value())) if self._meta.has_auto_field and not pk_set: setattr(self, self._meta.pk.attname, backend.get_last_insert_id(cursor, self._meta.db_table, self._meta.pk.column)) transaction.commit_unless_managed() # Run any post-save hooks. dispatcher.send(signal=signals.post_save, sender=self.__class__, instance=self) save.alters_data = True def validate(self): """ First coerces all fields on this instance to their proper Python types. Then runs validation on every field. Returns a dictionary of field_name -> error_list. """ error_dict = {} invalid_python = {} for f in self._meta.fields: try: setattr(self, f.attname, f.to_python(getattr(self, f.attname, f.get_default()))) except validators.ValidationError, e: error_dict[f.name] = e.messages invalid_python[f.name] = 1 for f in self._meta.fields: if f.name in invalid_python: continue errors = f.validate_full(getattr(self, f.attname, f.get_default()), self.__dict__) if errors: error_dict[f.name] = errors return error_dict def _collect_sub_objects(self, seen_objs): """ Recursively populates seen_objs with all objects related to this object. When done, seen_objs will be in the format: {model_class: {pk_val: obj, pk_val: obj, ...}, model_class: {pk_val: obj, pk_val: obj, ...}, ...} """ pk_val = self._get_pk_val() if pk_val in seen_objs.setdefault(self.__class__, {}): return seen_objs.setdefault(self.__class__, {})[pk_val] = self for related in self._meta.get_all_related_objects(): rel_opts_name = related.get_accessor_name() if isinstance(related.field.rel, OneToOneRel): try: sub_obj = getattr(self, rel_opts_name) except ObjectDoesNotExist: pass else: sub_obj._collect_sub_objects(seen_objs) else: for sub_obj in getattr(self, rel_opts_name).all(): sub_obj._collect_sub_objects(seen_objs) def delete(self): assert self._get_pk_val() is not None, "%s object can't be deleted because its %s attribute is set to None." % (self._meta.object_name, self._meta.pk.attname) # Find all the objects than need to be deleted seen_objs = SortedDict() self._collect_sub_objects(seen_objs) # Actually delete the objects delete_objects(seen_objs) delete.alters_data = True def _get_FIELD_display(self, field): value = getattr(self, field.attname) return dict(field.choices).get(value, value) def _get_next_or_previous_by_FIELD(self, field, is_next, **kwargs): op = is_next and '>' or '<' where = '(%s %s %%s OR (%s = %%s AND %s.%s %s %%s))' % \ (backend.quote_name(field.column), op, backend.quote_name(field.column), backend.quote_name(self._meta.db_table), backend.quote_name(self._meta.pk.column), op) param = str(getattr(self, field.attname)) q = self.__class__._default_manager.filter(**kwargs).order_by((not is_next and '-' or '') + field.name, (not is_next and '-' or '') + self._meta.pk.name) q._where.append(where) q._params.extend([param, param, getattr(self, self._meta.pk.attname)]) try: return q[0] except IndexError: raise self.DoesNotExist, "%s matching query does not exist." % self.__class__._meta.object_name def _get_next_or_previous_in_order(self, is_next): cachename = "__%s_order_cache" % is_next if not hasattr(self, cachename): op = is_next and '>' or '<' order_field = self._meta.order_with_respect_to where = ['%s %s (SELECT %s FROM %s WHERE %s=%%s)' % \ (backend.quote_name('_order'), op, backend.quote_name('_order'), backend.quote_name(self._meta.db_table), backend.quote_name(self._meta.pk.column)), '%s=%%s' % backend.quote_name(order_field.column)] params = [self._get_pk_val(), getattr(self, order_field.attname)] obj = self._default_manager.order_by('_order').extra(where=where, params=params)[:1].get() setattr(self, cachename, obj) return getattr(self, cachename) def _get_FIELD_filename(self, field): if getattr(self, field.attname): # value is not blank return os.path.join(settings.MEDIA_ROOT, getattr(self, field.attname)) return '' def _get_FIELD_url(self, field): if getattr(self, field.attname): # value is not blank import urlparse return urlparse.urljoin(settings.MEDIA_URL, getattr(self, field.attname)).replace('\\', '/') return '' def _get_FIELD_size(self, field): return os.path.getsize(self._get_FIELD_filename(field)) def _save_FIELD_file(self, field, filename, raw_contents): directory = field.get_directory_name() try: # Create the date-based directory if it doesn't exist. os.makedirs(os.path.join(settings.MEDIA_ROOT, directory)) except OSError: # Directory probably already exists. pass filename = field.get_filename(filename) # If the filename already exists, keep adding an underscore to the name of # the file until the filename doesn't exist. while os.path.exists(os.path.join(settings.MEDIA_ROOT, filename)): try: dot_index = filename.rindex('.') except ValueError: # filename has no dot filename += '_' else: filename = filename[:dot_index] + '_' + filename[dot_index:] # Write the file to disk. setattr(self, field.attname, filename) full_filename = self._get_FIELD_filename(field) fp = open(full_filename, 'wb') fp.write(raw_contents) fp.close() # Save the width and/or height, if applicable. if isinstance(field, ImageField) and (field.width_field or field.height_field): from django.utils.images import get_image_dimensions width, height = get_image_dimensions(full_filename) if field.width_field: setattr(self, field.width_field, width) if field.height_field: setattr(self, field.height_field, height) # Save the object, because it has changed. self.save() _save_FIELD_file.alters_data = True def _get_FIELD_width(self, field): return self._get_image_dimensions(field)[0] def _get_FIELD_height(self, field): return self._get_image_dimensions(field)[1] def _get_image_dimensions(self, field): cachename = "__%s_dimensions_cache" % field.name if not hasattr(self, cachename): from django.utils.images import get_image_dimensions filename = self._get_FIELD_filename(field) setattr(self, cachename, get_image_dimensions(filename)) return getattr(self, cachename) ############################################ # HELPER FUNCTIONS (CURRIED MODEL METHODS) # ############################################ # ORDERING METHODS ######################### def method_set_order(ordered_obj, self, id_list): cursor = connection.cursor() # Example: "UPDATE poll_choices SET _order = %s WHERE poll_id = %s AND id = %s" sql = "UPDATE %s SET %s = %%s WHERE %s = %%s AND %s = %%s" % \ (backend.quote_name(ordered_obj._meta.db_table), backend.quote_name('_order'), backend.quote_name(ordered_obj._meta.order_with_respect_to.column), backend.quote_name(ordered_obj._meta.pk.column)) rel_val = getattr(self, ordered_obj._meta.order_with_respect_to.rel.field_name) cursor.executemany(sql, [(i, rel_val, j) for i, j in enumerate(id_list)]) transaction.commit_unless_managed() def method_get_order(ordered_obj, self): cursor = connection.cursor() # Example: "SELECT id FROM poll_choices WHERE poll_id = %s ORDER BY _order" sql = "SELECT %s FROM %s WHERE %s = %%s ORDER BY %s" % \ (backend.quote_name(ordered_obj._meta.pk.column), backend.quote_name(ordered_obj._meta.db_table), backend.quote_name(ordered_obj._meta.order_with_respect_to.column), backend.quote_name('_order')) rel_val = getattr(self, ordered_obj._meta.order_with_respect_to.rel.field_name) cursor.execute(sql, [rel_val]) return [r[0] for r in cursor.fetchall()] ############################################## # HELPER FUNCTIONS (CURRIED MODEL FUNCTIONS) # ############################################## def get_absolute_url(opts, func, self): return settings.ABSOLUTE_URL_OVERRIDES.get('%s.%s' % (opts.app_label, opts.module_name), func)(self)