458 lines
21 KiB
Python
458 lines
21 KiB
Python
import django.db.models.manipulators
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import django.db.models.manager
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from django.core import validators
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from django.core.exceptions import ObjectDoesNotExist
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from django.db.models.fields import AutoField, ImageField, FieldDoesNotExist
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from django.db.models.fields.related import OneToOneRel, ManyToOneRel
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from django.db.models.query import delete_objects
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from django.db.models.options import Options, AdminOptions
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from django.db import connection, backend, transaction
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from django.db.models import signals
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from django.db.models.loading import register_models, get_model
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from django.dispatch import dispatcher
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from django.utils.datastructures import SortedDict
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from django.utils.functional import curry
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from django.utils.encoding import smart_str, force_unicode
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from django.conf import settings
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from itertools import izip
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import types
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import sys
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import os
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class ModelBase(type):
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"Metaclass for all models"
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def __new__(cls, name, bases, attrs):
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# If this isn't a subclass of Model, don't do anything special.
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try:
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if not filter(lambda b: issubclass(b, Model), bases):
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return super(ModelBase, cls).__new__(cls, name, bases, attrs)
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except NameError:
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# 'Model' isn't defined yet, meaning we're looking at Django's own
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# Model class, defined below.
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return super(ModelBase, cls).__new__(cls, name, bases, attrs)
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# Create the class.
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new_class = type.__new__(cls, name, bases, {'__module__': attrs.pop('__module__')})
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new_class.add_to_class('_meta', Options(attrs.pop('Meta', None)))
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new_class.add_to_class('DoesNotExist', types.ClassType('DoesNotExist', (ObjectDoesNotExist,), {}))
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# Build complete list of parents
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for base in bases:
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# TODO: Checking for the presence of '_meta' is hackish.
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if '_meta' in dir(base):
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new_class._meta.parents.append(base)
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new_class._meta.parents.extend(base._meta.parents)
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if getattr(new_class._meta, 'app_label', None) is None:
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# Figure out the app_label by looking one level up.
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# For 'django.contrib.sites.models', this would be 'sites'.
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model_module = sys.modules[new_class.__module__]
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new_class._meta.app_label = model_module.__name__.split('.')[-2]
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# Bail out early if we have already created this class.
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m = get_model(new_class._meta.app_label, name, False)
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if m is not None:
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return m
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# Add all attributes to the class.
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for obj_name, obj in attrs.items():
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new_class.add_to_class(obj_name, obj)
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# Add Fields inherited from parents
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for parent in new_class._meta.parents:
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for field in parent._meta.fields:
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# Only add parent fields if they aren't defined for this class.
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try:
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new_class._meta.get_field(field.name)
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except FieldDoesNotExist:
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field.contribute_to_class(new_class, field.name)
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new_class._prepare()
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register_models(new_class._meta.app_label, new_class)
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# Because of the way imports happen (recursively), we may or may not be
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# the first class for this model to register with the framework. There
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# should only be one class for each model, so we must always return the
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# registered version.
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return get_model(new_class._meta.app_label, name, False)
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class Model(object):
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__metaclass__ = ModelBase
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def _get_pk_val(self):
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return getattr(self, self._meta.pk.attname)
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def __repr__(self):
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return smart_str(u'<%s: %s>' % (self.__class__.__name__, unicode(self)))
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def __str__(self):
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if hasattr(self, '__unicode__'):
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return force_unicode(self).encode('utf-8')
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return '%s object' % self.__class__.__name__
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def __eq__(self, other):
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return isinstance(other, self.__class__) and self._get_pk_val() == other._get_pk_val()
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def __ne__(self, other):
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return not self.__eq__(other)
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def __init__(self, *args, **kwargs):
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dispatcher.send(signal=signals.pre_init, sender=self.__class__, args=args, kwargs=kwargs)
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# There is a rather weird disparity here; if kwargs, it's set, then args
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# overrides it. It should be one or the other; don't duplicate the work
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# The reason for the kwargs check is that standard iterator passes in by
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# args, and nstantiation for iteration is 33% faster.
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args_len = len(args)
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if args_len > len(self._meta.fields):
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# Daft, but matches old exception sans the err msg.
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raise IndexError("Number of args exceeds number of fields")
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fields_iter = iter(self._meta.fields)
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if not kwargs:
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# The ordering of the izip calls matter - izip throws StopIteration
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# when an iter throws it. So if the first iter throws it, the second
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# is *not* consumed. We rely on this, so don't change the order
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# without changing the logic.
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for val, field in izip(args, fields_iter):
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setattr(self, field.attname, val)
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else:
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# Slower, kwargs-ready version.
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for val, field in izip(args, fields_iter):
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setattr(self, field.attname, val)
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kwargs.pop(field.name, None)
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# Maintain compatibility with existing calls.
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if isinstance(field.rel, ManyToOneRel):
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kwargs.pop(field.attname, None)
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# Now we're left with the unprocessed fields that *must* come from
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# keywords, or default.
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for field in fields_iter:
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if kwargs:
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if isinstance(field.rel, ManyToOneRel):
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try:
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# Assume object instance was passed in.
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rel_obj = kwargs.pop(field.name)
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except KeyError:
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try:
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# Object instance wasn't passed in -- must be an ID.
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val = kwargs.pop(field.attname)
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except KeyError:
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val = field.get_default()
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else:
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# Object instance was passed in. Special case: You can
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# pass in "None" for related objects if it's allowed.
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if rel_obj is None and field.null:
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val = None
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else:
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try:
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val = getattr(rel_obj, field.rel.get_related_field().attname)
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except AttributeError:
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raise TypeError("Invalid value: %r should be a %s instance, not a %s" %
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(field.name, field.rel.to, type(rel_obj)))
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else:
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val = kwargs.pop(field.attname, field.get_default())
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else:
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val = field.get_default()
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setattr(self, field.attname, val)
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if kwargs:
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for prop in kwargs.keys():
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try:
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if isinstance(getattr(self.__class__, prop), property):
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setattr(self, prop, kwargs.pop(prop))
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except AttributeError:
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pass
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if kwargs:
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raise TypeError, "'%s' is an invalid keyword argument for this function" % kwargs.keys()[0]
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dispatcher.send(signal=signals.post_init, sender=self.__class__, instance=self)
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def add_to_class(cls, name, value):
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if name == 'Admin':
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assert type(value) == types.ClassType, "%r attribute of %s model must be a class, not a %s object" % (name, cls.__name__, type(value))
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value = AdminOptions(**dict([(k, v) for k, v in value.__dict__.items() if not k.startswith('_')]))
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if hasattr(value, 'contribute_to_class'):
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value.contribute_to_class(cls, name)
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else:
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setattr(cls, name, value)
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add_to_class = classmethod(add_to_class)
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def _prepare(cls):
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# Creates some methods once self._meta has been populated.
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opts = cls._meta
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opts._prepare(cls)
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if opts.order_with_respect_to:
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cls.get_next_in_order = curry(cls._get_next_or_previous_in_order, is_next=True)
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cls.get_previous_in_order = curry(cls._get_next_or_previous_in_order, is_next=False)
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setattr(opts.order_with_respect_to.rel.to, 'get_%s_order' % cls.__name__.lower(), curry(method_get_order, cls))
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setattr(opts.order_with_respect_to.rel.to, 'set_%s_order' % cls.__name__.lower(), curry(method_set_order, cls))
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# Give the class a docstring -- its definition.
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if cls.__doc__ is None:
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cls.__doc__ = "%s(%s)" % (cls.__name__, ", ".join([f.attname for f in opts.fields]))
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if hasattr(cls, 'get_absolute_url'):
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cls.get_absolute_url = curry(get_absolute_url, opts, cls.get_absolute_url)
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dispatcher.send(signal=signals.class_prepared, sender=cls)
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_prepare = classmethod(_prepare)
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def save(self, raw=False):
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dispatcher.send(signal=signals.pre_save, sender=self.__class__, instance=self)
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non_pks = [f for f in self._meta.fields if not f.primary_key]
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cursor = connection.cursor()
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# First, try an UPDATE. If that doesn't update anything, do an INSERT.
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pk_val = self._get_pk_val()
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pk_set = bool(pk_val)
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record_exists = True
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if pk_set:
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# Determine whether a record with the primary key already exists.
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cursor.execute("SELECT COUNT(*) FROM %s WHERE %s=%%s" % \
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(backend.quote_name(self._meta.db_table), backend.quote_name(self._meta.pk.column)),
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self._meta.pk.get_db_prep_lookup('exact', pk_val))
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# If it does already exist, do an UPDATE.
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if cursor.fetchone()[0] > 0:
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db_values = [f.get_db_prep_save(raw and getattr(self, f.attname) or f.pre_save(self, False)) for f in non_pks]
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if db_values:
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cursor.execute("UPDATE %s SET %s WHERE %s=%%s" % \
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(backend.quote_name(self._meta.db_table),
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','.join(['%s=%%s' % backend.quote_name(f.column) for f in non_pks]),
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backend.quote_name(self._meta.pk.column)),
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db_values + self._meta.pk.get_db_prep_lookup('exact', pk_val))
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else:
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record_exists = False
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if not pk_set or not record_exists:
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field_names = [backend.quote_name(f.column) for f in self._meta.fields if not isinstance(f, AutoField)]
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db_values = [f.get_db_prep_save(raw and getattr(self, f.attname) or f.pre_save(self, True)) for f in self._meta.fields if not isinstance(f, AutoField)]
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# If the PK has been manually set, respect that.
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if pk_set:
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field_names += [f.column for f in self._meta.fields if isinstance(f, AutoField)]
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db_values += [f.get_db_prep_save(raw and getattr(self, f.attname) or f.pre_save(self, True)) for f in self._meta.fields if isinstance(f, AutoField)]
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placeholders = ['%s'] * len(field_names)
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if self._meta.order_with_respect_to:
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field_names.append(backend.quote_name('_order'))
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# TODO: This assumes the database supports subqueries.
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placeholders.append('(SELECT COUNT(*) FROM %s WHERE %s = %%s)' % \
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(backend.quote_name(self._meta.db_table), backend.quote_name(self._meta.order_with_respect_to.column)))
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db_values.append(getattr(self, self._meta.order_with_respect_to.attname))
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if db_values:
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cursor.execute("INSERT INTO %s (%s) VALUES (%s)" % \
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(backend.quote_name(self._meta.db_table), ','.join(field_names),
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','.join(placeholders)), db_values)
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else:
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# Create a new record with defaults for everything.
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cursor.execute("INSERT INTO %s (%s) VALUES (%s)" %
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(backend.quote_name(self._meta.db_table),
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backend.quote_name(self._meta.pk.column),
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backend.get_pk_default_value()))
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if self._meta.has_auto_field and not pk_set:
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setattr(self, self._meta.pk.attname, backend.get_last_insert_id(cursor, self._meta.db_table, self._meta.pk.column))
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transaction.commit_unless_managed()
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# Run any post-save hooks.
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dispatcher.send(signal=signals.post_save, sender=self.__class__, instance=self)
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save.alters_data = True
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def validate(self):
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"""
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First coerces all fields on this instance to their proper Python types.
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Then runs validation on every field. Returns a dictionary of
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field_name -> error_list.
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"""
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error_dict = {}
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invalid_python = {}
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for f in self._meta.fields:
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try:
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setattr(self, f.attname, f.to_python(getattr(self, f.attname, f.get_default())))
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except validators.ValidationError, e:
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error_dict[f.name] = e.messages
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invalid_python[f.name] = 1
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for f in self._meta.fields:
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if f.name in invalid_python:
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continue
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errors = f.validate_full(getattr(self, f.attname, f.get_default()), self.__dict__)
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if errors:
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error_dict[f.name] = errors
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return error_dict
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def _collect_sub_objects(self, seen_objs):
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"""
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Recursively populates seen_objs with all objects related to this object.
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When done, seen_objs will be in the format:
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{model_class: {pk_val: obj, pk_val: obj, ...},
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model_class: {pk_val: obj, pk_val: obj, ...}, ...}
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"""
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pk_val = self._get_pk_val()
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if pk_val in seen_objs.setdefault(self.__class__, {}):
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return
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seen_objs.setdefault(self.__class__, {})[pk_val] = self
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for related in self._meta.get_all_related_objects():
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rel_opts_name = related.get_accessor_name()
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if isinstance(related.field.rel, OneToOneRel):
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try:
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sub_obj = getattr(self, rel_opts_name)
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except ObjectDoesNotExist:
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pass
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else:
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sub_obj._collect_sub_objects(seen_objs)
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else:
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for sub_obj in getattr(self, rel_opts_name).all():
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sub_obj._collect_sub_objects(seen_objs)
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def delete(self):
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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)
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# Find all the objects than need to be deleted
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seen_objs = SortedDict()
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self._collect_sub_objects(seen_objs)
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# Actually delete the objects
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delete_objects(seen_objs)
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delete.alters_data = True
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def _get_FIELD_display(self, field):
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value = getattr(self, field.attname)
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return force_unicode(dict(field.choices).get(value, value), strings_only=True)
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def _get_next_or_previous_by_FIELD(self, field, is_next, **kwargs):
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op = is_next and '>' or '<'
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where = '(%s %s %%s OR (%s = %%s AND %s.%s %s %%s))' % \
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(backend.quote_name(field.column), op, backend.quote_name(field.column),
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backend.quote_name(self._meta.db_table), backend.quote_name(self._meta.pk.column), op)
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param = smart_str(getattr(self, field.attname))
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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)
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q._where.append(where)
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q._params.extend([param, param, getattr(self, self._meta.pk.attname)])
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try:
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return q[0]
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except IndexError:
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raise self.DoesNotExist, "%s matching query does not exist." % self.__class__._meta.object_name
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def _get_next_or_previous_in_order(self, is_next):
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cachename = "__%s_order_cache" % is_next
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if not hasattr(self, cachename):
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op = is_next and '>' or '<'
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order_field = self._meta.order_with_respect_to
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where = ['%s %s (SELECT %s FROM %s WHERE %s=%%s)' % \
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(backend.quote_name('_order'), op, backend.quote_name('_order'),
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backend.quote_name(self._meta.db_table), backend.quote_name(self._meta.pk.column)),
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'%s=%%s' % backend.quote_name(order_field.column)]
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params = [self._get_pk_val(), getattr(self, order_field.attname)]
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obj = self._default_manager.order_by('_order').extra(where=where, params=params)[:1].get()
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setattr(self, cachename, obj)
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return getattr(self, cachename)
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def _get_FIELD_filename(self, field):
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if getattr(self, field.attname): # value is not blank
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return os.path.join(settings.MEDIA_ROOT, getattr(self, field.attname))
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return ''
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def _get_FIELD_url(self, field):
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if getattr(self, field.attname): # value is not blank
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import urlparse
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return urlparse.urljoin(settings.MEDIA_URL, getattr(self, field.attname)).replace('\\', '/')
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return ''
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def _get_FIELD_size(self, field):
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return os.path.getsize(self._get_FIELD_filename(field))
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def _save_FIELD_file(self, field, filename, raw_contents, save=True):
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directory = field.get_directory_name()
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try: # Create the date-based directory if it doesn't exist.
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os.makedirs(os.path.join(settings.MEDIA_ROOT, directory))
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except OSError: # Directory probably already exists.
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pass
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filename = field.get_filename(filename)
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# If the filename already exists, keep adding an underscore to the name of
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# the file until the filename doesn't exist.
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while os.path.exists(os.path.join(settings.MEDIA_ROOT, filename)):
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try:
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dot_index = filename.rindex('.')
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except ValueError: # filename has no dot
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filename += '_'
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else:
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filename = filename[:dot_index] + '_' + filename[dot_index:]
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# Write the file to disk.
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setattr(self, field.attname, filename)
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full_filename = self._get_FIELD_filename(field)
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fp = open(full_filename, 'wb')
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fp.write(raw_contents)
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fp.close()
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# Save the width and/or height, if applicable.
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if isinstance(field, ImageField) and (field.width_field or field.height_field):
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from django.utils.images import get_image_dimensions
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width, height = get_image_dimensions(full_filename)
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if field.width_field:
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setattr(self, field.width_field, width)
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if field.height_field:
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setattr(self, field.height_field, height)
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# Save the object because it has changed unless save is False
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if save:
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self.save()
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_save_FIELD_file.alters_data = True
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def _get_FIELD_width(self, field):
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return self._get_image_dimensions(field)[0]
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def _get_FIELD_height(self, field):
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return self._get_image_dimensions(field)[1]
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def _get_image_dimensions(self, field):
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cachename = "__%s_dimensions_cache" % field.name
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if not hasattr(self, cachename):
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from django.utils.images import get_image_dimensions
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filename = self._get_FIELD_filename(field)
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setattr(self, cachename, get_image_dimensions(filename))
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return getattr(self, cachename)
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############################################
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# HELPER FUNCTIONS (CURRIED MODEL METHODS) #
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############################################
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# ORDERING METHODS #########################
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def method_set_order(ordered_obj, self, id_list):
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cursor = connection.cursor()
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# Example: "UPDATE poll_choices SET _order = %s WHERE poll_id = %s AND id = %s"
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sql = "UPDATE %s SET %s = %%s WHERE %s = %%s AND %s = %%s" % \
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(backend.quote_name(ordered_obj._meta.db_table), backend.quote_name('_order'),
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backend.quote_name(ordered_obj._meta.order_with_respect_to.column),
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backend.quote_name(ordered_obj._meta.pk.column))
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rel_val = getattr(self, ordered_obj._meta.order_with_respect_to.rel.field_name)
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cursor.executemany(sql, [(i, rel_val, j) for i, j in enumerate(id_list)])
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transaction.commit_unless_managed()
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def method_get_order(ordered_obj, self):
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cursor = connection.cursor()
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# Example: "SELECT id FROM poll_choices WHERE poll_id = %s ORDER BY _order"
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sql = "SELECT %s FROM %s WHERE %s = %%s ORDER BY %s" % \
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(backend.quote_name(ordered_obj._meta.pk.column),
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backend.quote_name(ordered_obj._meta.db_table),
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backend.quote_name(ordered_obj._meta.order_with_respect_to.column),
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backend.quote_name('_order'))
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rel_val = getattr(self, ordered_obj._meta.order_with_respect_to.rel.field_name)
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cursor.execute(sql, [rel_val])
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return [r[0] for r in cursor.fetchall()]
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##############################################
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# HELPER FUNCTIONS (CURRIED MODEL FUNCTIONS) #
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##############################################
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def get_absolute_url(opts, func, self):
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return settings.ABSOLUTE_URL_OVERRIDES.get('%s.%s' % (opts.app_label, opts.module_name), func)(self)
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