/
manager.py
1254 lines (1073 loc) · 51.3 KB
/
manager.py
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from collections import defaultdict
import django
from django.conf import settings
from django.core.exceptions import FieldError
from django.db import connections, models, transaction, IntegrityError
if django.VERSION >= (1, 9):
from django.db.models.query import QuerySet
elif django.VERSION >= (1, 8):
from django.db.models.query import QuerySet, ValuesQuerySet
else:
from django.db.models.query import QuerySet, ValuesQuerySet, DateQuerySet, DateTimeQuerySet
if django.VERSION >= (1, 8):
from django.db.models.sql.datastructures import Join, LOUTER
from django.db.models.sql.constants import GET_ITERATOR_CHUNK_SIZE as CHUNK_SIZE
from django.db.models import F, Q
from django.utils.translation import get_language
from hvad.compat import string_types
from hvad.query import (query_terms, q_children, expression_nodes, where_node_children,
add_alias_constraints)
from hvad.utils import combine, minimumDjangoVersion, settings_updater
from copy import deepcopy
import logging
import sys
import warnings
#===============================================================================
# Logging-related globals
_logger = logging.getLogger(__name__)
# Global settings, wrapped so they react to SettingsOverride
@settings_updater
def update_settings(*args, **kwargs):
global FALLBACK_LANGUAGES, LEGACY_FALLBACKS
FALLBACK_LANGUAGES = tuple(code for code, name in settings.LANGUAGES)
LEGACY_FALLBACKS = bool(getattr(settings, 'HVAD_LEGACY_FALLBACKS', False))
#===============================================================================
class FieldTranslator(object):
"""
Translates *shared* field names from '<shared_field>' to
'master__<shared_field>' and caches those names.
"""
def __init__(self, manager):
self._manager = manager
if django.VERSION >= (1, 8):
fields = set()
for field in manager.shared_model._meta.get_fields():
fields.add(field.name)
if hasattr(field, 'attname'):
fields.add(field.attname)
fields.add('pk')
self._shared_fields = tuple(fields)
else:
self._shared_fields = tuple(manager.shared_model._meta.get_all_field_names()) + ('pk',)
self._cache = dict()
super(FieldTranslator, self).__init__()
def __call__(self, key):
try:
ret = self._cache[key]
except KeyError:
ret = self._build(key)
self._cache[key] = ret
return ret
def _build(self, key):
"""
Checks if the selected field is a shared field
and in that case, prefixes it with master___
It also handles - and ? in case its called by
order_by()
"""
if key == "?":
return key
if key.startswith("-"):
prefix, key = "-", key[1:]
else:
prefix = ""
if key.startswith(self._shared_fields):
return '%smaster__%s' % (prefix, key)
else:
return '%s%s' % (prefix, key)
#===============================================================================
if django.VERSION >= (1, 9):
from django.db.models.query import ValuesIterable, ValuesListIterable, FlatValuesListIterable
class TranslatedValuesIterable(ValuesIterable):
def __iter__(self):
queryset = self.queryset
for row in super(TranslatedValuesIterable, self).__iter__():
yield queryset._reverse_translate_fieldnames_dict(row)
iterable_overrides = {
ValuesIterable: TranslatedValuesIterable,
ValuesListIterable: ValuesListIterable,
FlatValuesListIterable: FlatValuesListIterable,
}
else:
class ValuesMixin(object):
_skip_master_select = True
def iterator(self):
qs = self._clone()._add_language_filter()
for row in super(ValuesMixin, qs).iterator():
if isinstance(row, dict):
yield qs._reverse_translate_fieldnames_dict(row)
else:
yield row
class SkipMasterSelectMixin(object):
_skip_master_select = True
#===============================================================================
class ForcedUniqueFields(object):
""" Context manager that forces a set of fields to be unique while active """
def __init__(self, fields):
self.fields = fields
def __enter__(self):
for field in self.fields:
field._unique = True
def __exit__(self, *args):
for field in self.fields:
field._unique = False
#===============================================================================
# Field for language joins
#===============================================================================
class RawConstraint(object):
def __init__(self, sql, aliases):
self.sql = sql
self.aliases = aliases
def as_sql(self, compiler, connection):
aliases = tuple(compiler.quote_name_unless_alias(alias) for alias in self.aliases)
return (self.sql % aliases, [])
class BetterTranslationsField(object):
def __init__(self, translation_fallbacks, master):
# Filter out duplicates, while preserving order
self._fallbacks = []
self._master = master
seen = set()
for lang in translation_fallbacks:
if lang not in seen:
seen.add(lang)
self._fallbacks.append(lang)
def get_extra_restriction(self, where_class, alias, related_alias):
langcase = ('(CASE %s.language_code ' +
' '.join('WHEN \'%s\' THEN %d' % (lang, i)
for i, lang in enumerate(self._fallbacks)) +
' ELSE %d END)' % len(self._fallbacks))
return RawConstraint(
sql=' '.join((langcase, '<', langcase, 'OR ('
'%s.language_code = %s.language_code AND '
'%s.id < %s.id)')),
aliases=(alias, related_alias,
alias, related_alias,
alias, related_alias)
)
@minimumDjangoVersion(1, 8)
def get_joining_columns(self):
return ((self._master, self._master), )
#===============================================================================
# TranslationQueryset
#===============================================================================
class TranslationQueryset(QuerySet):
"""
This is where things happen.
To fully understand this project, you have to understand this class.
Go through each method individually, maybe start with 'get', 'create' and
'iterator'.
IMPORTANT: the `model` attribute on this class is the *translated* Model,
despite this being used as the queryset for the *shared* Model!
"""
override_classes = {}
if django.VERSION < (1, 9):
override_classes[ValuesQuerySet] = ValuesMixin
if django.VERSION < (1, 8):
override_classes[DateQuerySet] = SkipMasterSelectMixin
override_classes[DateTimeQuerySet] = SkipMasterSelectMixin
_skip_master_select = False
def __init__(self, *args, **kwargs):
# model can be either first positional, or a named arg
if len(args) >= 1:
model, args = args[0], args[1:]
else:
model = kwargs.pop('model', None)
if model is not None: # check the given model is correct
if hasattr(model._meta, 'translations_model'):
# normal creation gets a shared model that we must flip around
model, self.shared_model = model._meta.translations_model, model
elif not hasattr(model._meta, 'shared_model'):
raise TypeError('TranslationQueryset only works on translatable models')
self._local_field_names = None
self._field_translator = None
self._language_code = None
self._language_fallbacks = None
self._raw_select_related = []
self._forced_unique_fields = [] # Used for select_related
self._language_filter_tag = False
self._hvad_switch_fields = ()
super(TranslationQueryset, self).__init__(model, *args, **kwargs)
#===========================================================================
# Helpers and properties (INTERNAL!)
#===========================================================================
def _clone(self, klass=None, setup=False, **kwargs):
""" Creates a clone of this queryset - Django equivalent of copy()
This method keeps all defining attributes and drops data caches
"""
kwargs.update({
'shared_model': self.shared_model,
'_local_field_names': self._local_field_names,
'_field_translator': self._field_translator,
'_language_code': self._language_code,
'_language_fallbacks': self._language_fallbacks,
'_raw_select_related': self._raw_select_related,
'_forced_unique_fields': list(self._forced_unique_fields),
'_language_filter_tag': getattr(self, '_language_filter_tag', False),
'_hvad_switch_fields': self._hvad_switch_fields,
})
if django.VERSION < (1, 9):
kwargs.update({
'klass': None if klass is None else self._get_class(klass),
'setup': setup,
})
return super(TranslationQueryset, self)._clone(**kwargs)
@property
def field_translator(self):
if self._field_translator is None:
self._field_translator = FieldTranslator(self)
return self._field_translator
@property
def shared_local_field_names(self):
if self._local_field_names is None:
if django.VERSION >= (1, 8):
fields = set()
for field in self.shared_model._meta.get_fields():
fields.add(field.name)
if hasattr(field, 'attname'):
fields.add(field.attname)
self._local_field_names = tuple(fields)
else:
self._local_field_names = self.shared_model._meta.get_all_field_names()
return self._local_field_names
def _translate_args_kwargs(self, *args, **kwargs):
# Translate args (Q objects) from '<shared_field>' to
# 'master__<shared_field>' where necessary.
newargs = deepcopy(args)
for q in newargs:
for child, children, index in q_children(q):
children[index] = (self.field_translator(child[0]), child[1])
# Translated kwargs from '<shared_field>' to 'master__<shared_field>'
# where necessary.
newkwargs = dict((self.field_translator(key), value)
for key, value in kwargs.items())
return newargs, newkwargs
def _translate_expression(self, expr):
if isinstance(expr, string_types):
return self.field_translator(expr)
for node in expression_nodes(expr):
if isinstance(node, F):
node.name = self.field_translator(node.name)
elif hasattr(node, 'lookup'):
node.lookup = self.field_translator(node.lookup)
return expr
def _translate_fieldnames(self, fieldnames):
annotations = (self.query.annotations if django.VERSION >= (1, 8)
else self.query.aggregates)
return [name if name in annotations
else self.field_translator(name)
for name in fieldnames]
def _reverse_translate_fieldnames_dict(self, fieldname_dict):
"""
Helper function to make sure the user doesnt get "bothered"
with the construction of shared/translated model
Translates e.g.
{'master__number_avg': 10} to {'number__avg': 10}
"""
prefix = 'master__'
return dict(
(key[len(prefix):] if key.startswith(prefix) else key, value)
for key, value in fieldname_dict.items()
)
def _split_kwargs(self, **kwargs):
"""
Split kwargs into shared and translated fields
"""
shared = {}
translated = {}
for key, value in kwargs.items():
if key in self.shared_local_field_names:
shared[key] = value
else:
translated[key] = value
return shared, translated
def _get_class(self, klass):
for key, value in self.override_classes.items():
if issubclass(klass, key):
return type(value.__name__, (value, klass, TranslationQueryset,), {})
else: # pragma: no cover
return klass
def _get_shared_queryset(self):
qs = super(TranslationQueryset, self)._clone()
qs.__class__ = QuerySet
accessor = self.shared_model._meta.translations_accessor
# update using the real manager
return QuerySet(self.shared_model, using=self.db).filter(**{'%s__in' % accessor: qs})
def _add_select_related(self, language_code):
fields = self._raw_select_related
related_queries = []
language_filters = []
force_unique_fields = []
if not self._skip_master_select and getattr(self, '_fields', None) is None:
related_queries.append('master')
for query_key in fields:
newbits = []
for term in query_terms(self.shared_model, query_key):
# Translate term
if term.depth == 0 and not term.translated:
# on initial depth we must key to shared model
newbits.append('master__%s' % term.term)
elif term.depth > 0 and term.translated:
# on deeper levels we must key to translations model
# this will work because translations will be seen as _unique
# at query time
newbits.append('%s__%s' % (term.model._meta.translations_accessor, term.term))
else:
newbits.append(term.term)
# Some helpful messages for common mistakes
if term.many:
raise FieldError('Cannot select_related: %s can be multiple objects. '
'Use prefetch_related instead.' % query_key)
if term.target is None:
raise FieldError('Cannot select_related: %s is a regular field' % query_key)
if hasattr(term.field.rel, 'through'):
raise FieldError('Cannot select_related: %s can be multiple objects. '
'Use prefetch_related instead.' % query_key)
# If target is a translated model, select its translations
target_translations = getattr(term.target._meta, 'translations_accessor', None)
if target_translations is not None:
# Add the model
target_query = '__'.join(newbits)
related_queries.append('%s__%s' % (target_query, target_translations))
# Add a language filter for the translation
language_filters.append('%s__%s__language_code' % (
target_query,
target_translations,
))
# Remember to mark the field unique so JOIN is generated
# and row decoder gets cached items
if django.VERSION >= (1, 9):
target_transfield = getattr(term.target, target_translations).field
else:
target_transfield = getattr(term.target, target_translations).related.field
force_unique_fields.append(target_transfield)
related_queries.append('__'.join(newbits))
# Apply results to query
self.query.add_select_related(related_queries)
for language_filter in language_filters:
self.query.add_q(Q(**{language_filter: language_code}) |
Q(**{language_filter: None}))
self._forced_unique_fields = force_unique_fields
def _add_language_filter(self):
if self._language_filter_tag: # pragma: no cover
raise RuntimeError('Queryset is already tagged. This is a bug in hvad')
self._language_filter_tag = True
if self._language_code == 'all':
self._add_select_related(F('language_code'))
elif self._language_fallbacks:
if self._raw_select_related:
raise NotImplementedError('Using select_related along with '
'fallbacks() is not supported')
languages = tuple(get_language() if lang is None else lang
for lang in (self._language_code,) + self._language_fallbacks)
if django.VERSION >= (1, 8):
masteratt = self.model._meta.get_field('master').attname
alias = self.query.join(Join(
self.model._meta.db_table,
self.query.get_initial_alias(),
None,
LOUTER,
BetterTranslationsField(languages, master=masteratt),
True
))
else:
masteratt = self.model._meta.get_field('master').attname
nullable = {'nullable': True}
alias = self.query.join((self.query.get_initial_alias(), self.model._meta.db_table,
((masteratt, masteratt),)),
join_field=BetterTranslationsField(languages, master=masteratt),
**nullable)
add_alias_constraints(self, (self.model, alias), id__isnull=True)
self.query.add_filter(('%s__isnull' % masteratt, False))
if not self._skip_master_select and getattr(self, '_fields', None) is None:
self.query.add_select_related(('master',))
else:
language_code = self._language_code or get_language()
self.query.add_filter(('language_code', language_code))
self._add_select_related(language_code)
# if queryset is about to use the model's default ordering, we
# override that now with a translated version of the model's ordering
if self.query.default_ordering and not self.query.order_by:
ordering = self.shared_model._meta.ordering
self.query.order_by = self._translate_fieldnames(ordering or [])
return self
def _use_related_translations(self, obj, relations_dict, depth=0):
"""
Ensure that we use cached translations brought in via select_related if
available. Necessary since the database select_related query caches the
related translation models in a different place than hvad expects it.
"""
# First, set translation for current object,
accessor = getattr(obj._meta, 'translations_accessor', None)
if accessor is not None:
if django.VERSION >= (1, 9):
cache = getattr(obj.__class__, accessor).rel.get_cache_name()
else:
cache = getattr(obj.__class__, accessor).related.get_cache_name()
try:
translation = getattr(obj, cache)
except AttributeError:
pass
else:
delattr(obj, cache)
setattr(obj, obj._meta.translations_cache, translation)
# Then recurse in the relation dict
for field, sub_dict in relations_dict.items():
target = translation if field == accessor else getattr(obj, field)
if target is not None:
self._use_related_translations(target, sub_dict, depth+1)
#===========================================================================
# Queryset/Manager API
#===========================================================================
def language(self, language_code=None):
self._language_code = language_code
return self
def fallbacks(self, *fallbacks):
if not fallbacks:
self._language_fallbacks = FALLBACK_LANGUAGES
elif fallbacks == (None,):
self._language_fallbacks = None
else:
self._language_fallbacks = fallbacks
return self
#===========================================================================
# Queryset/Manager API that do database queries
#===========================================================================
def iterator(self):
"""
If this queryset is not filtered by a language code yet, it should be
filtered first by calling self.language.
If someone doesn't want a queryset filtered by language, they should use
Model.objects.untranslated()
"""
qs = self._clone()._add_language_filter()
qs._known_related_objects = {} # super's iterator will attempt to set them
if django.VERSION >= (1, 9) and qs._iterable_class in iterable_overrides:
qs._iterable_class = iterable_overrides[qs._iterable_class]
for obj in super(TranslationQueryset, qs).iterator():
yield obj
return
if qs._forced_unique_fields:
# HACK: In order for select_related to properly load data from
# translated models, we have to force django to treat
# certain fields as one-to-one relations
# before this queryset calls get_cached_row()
# We change it back so that things get reset to normal
# before execution returns to user code.
# It would be more direct and robust if we could wrap
# django.db.models.query.get_cached_row() instead, but that's not a class
# method, sadly, so we cannot override it just for this query
with ForcedUniqueFields(qs._forced_unique_fields):
# Pre-fetch all objects:
objects = list(super(TranslationQueryset, qs).iterator())
if type(qs.query.select_related) == dict:
for obj in objects:
qs._use_related_translations(obj, qs.query.select_related)
else:
objects = super(TranslationQueryset, qs).iterator()
for obj in objects:
for name in self._hvad_switch_fields:
try:
setattr(obj.master, name, getattr(obj, name))
except AttributeError: # pragma: no cover
pass
else:
delattr(obj, name)
obj = combine(obj, qs.shared_model)
# use known objects from self, not qs as we cleared it earlier
for field, rel_objs in self._known_related_objects.items():
if hasattr(obj, field.get_cache_name()):
# should not happen, but we conform to Django behavior
continue #pragma: no cover
pk = getattr(obj, field.get_attname())
try:
rel_obj = rel_objs[pk]
except KeyError: #pragma: no cover
pass
else:
setattr(obj, field.name, rel_obj)
yield obj
def create(self, **kwargs):
if 'language_code' not in kwargs:
kwargs['language_code'] = self._language_code or get_language()
elif self._language_code is not None:
raise ValueError('Overriding language_code in create() is not allowed. '
'Please set the language with language() instead.')
if kwargs['language_code'] == 'all':
raise ValueError('Cannot create an object with language \'all\'')
obj = self.shared_model(**kwargs)
self._for_write = True
obj.save(force_insert=True, using=self.db)
return obj
def count(self):
if self._result_cache is None:
qs = self._clone()._add_language_filter()
return super(TranslationQueryset, qs).count()
else:
return len(self._result_cache)
def exists(self):
if self._result_cache is None:
qs = self._clone()._add_language_filter()
return super(TranslationQueryset, qs).exists()
else:
return bool(self._result_cache)
def get_or_create(self, **kwargs):
"""
Looks up an object with the given kwargs, creating one if necessary.
Returns a tuple of (object, created), where created is a boolean
specifying whether an object was created.
"""
assert kwargs, \
'get_or_create() must be passed at least one keyword argument'
defaults = kwargs.pop('defaults', {})
lookup = kwargs.copy()
for f in self.model._meta.fields:
if f.attname in lookup:
lookup[f.name] = lookup.pop(f.attname)
try:
self._for_write = True
return self.get(**lookup), False
except self.model.DoesNotExist:
pass
params = dict([(k, v) for k, v in kwargs.items() if '__' not in k])
params.update(defaults)
if 'language_code' not in params:
params['language_code'] = self._language_code or get_language()
elif self._language_code is not None:
raise ValueError('Overriding language_code in get_or_create() is not allowed. '
'Please set the language with language() instead.')
if params['language_code'] == 'all':
raise ValueError('Cannot create an object with language \'all\'')
obj = self.shared_model(**params)
try:
with transaction.atomic(using=self.db):
obj.save(force_insert=True, using=self.db)
return obj, True
except IntegrityError:
exc_info = sys.exc_info()
try:
return self.get(**lookup), False
except self.model.DoesNotExist:
raise exc_info[1]
def update_or_create(self, defaults=None, **kwargs):
raise NotImplementedError()
def bulk_create(self, objs, batch_size=None):
raise NotImplementedError()
def aggregate(self, *args, **kwargs):
"""
Loops over all the passed aggregates and translates the fieldnames
"""
qs = self._clone()._add_language_filter()
newargs = tuple(qs._translate_expression(item) for item in args)
newkwargs = dict(
(k, qs._translate_expression(v)) for k, v in kwargs.items()
)
response = super(TranslationQueryset, qs).aggregate(*newargs, **newkwargs)
return qs._reverse_translate_fieldnames_dict(response)
def latest(self, field_name=None):
field_name = self.field_translator(field_name or self.shared_model._meta.get_latest_by)
return super(TranslationQueryset, self).latest(field_name)
def earliest(self, field_name=None):
field_name = self.field_translator(field_name or self.shared_model._meta.get_latest_by)
return super(TranslationQueryset, self).earliest(field_name)
def in_bulk(self, id_list):
if not id_list:
return {}
if self._language_code == 'all':
raise ValueError('Cannot use in_bulk along with language(\'all\').')
qs = self.filter(pk__in=id_list)
qs.query.clear_ordering(force_empty=True)
return dict((obj._get_pk_val(), obj) for obj in qs.iterator())
def delete(self):
qs = self._get_shared_queryset()
qs.delete()
delete.alters_data = True
delete.queryset_only = True
def delete_translations(self):
if connections[self._db].features.update_can_self_select:
qs = self._clone()._add_language_filter()
super(TranslationQueryset, qs).delete()
else:
with transaction.atomic(using=self._db, savepoint=False):
pks = list(super(TranslationQueryset, self).values_list('pk', flat=True))
self.model._base_manager.filter(pk__in=pks).delete()
delete_translations.alters_data = True
def update(self, **kwargs):
qs = self._clone()._add_language_filter()
shared, translated = qs._split_kwargs(**kwargs)
count = 0
if translated:
count += super(TranslationQueryset, qs).update(**translated)
if shared:
shared_qs = qs._get_shared_queryset()
count += shared_qs.update(**shared)
return count
update.alters_data = True
#===========================================================================
# Queryset/Manager API that return another queryset
#===========================================================================
def filter(self, *args, **kwargs):
if 'language_code' in kwargs and kwargs['language_code'] == 'all':
raise ValueError('Value "all" is invalid for language_code')
newargs, newkwargs = self._translate_args_kwargs(*args, **kwargs)
return super(TranslationQueryset, self).filter(*newargs, **newkwargs)
def exclude(self, *args, **kwargs):
if 'language_code' in kwargs and kwargs['language_code'] == 'all':
raise ValueError('Value "all" is invalid for language_code')
newargs, newkwargs = self._translate_args_kwargs(*args, **kwargs)
return super(TranslationQueryset, self).exclude(*newargs, **newkwargs)
def extra(self, select=None, where=None, params=None, tables=None,
order_by=None, select_params=None):
qs = super(TranslationQueryset, self).extra(select, where, params, tables,
order_by, select_params)
if select:
switch_fields = set(self._hvad_switch_fields)
switch_fields.update(select.keys())
qs._hvad_switch_fields = tuple(switch_fields)
return qs
def values(self, *fields):
fields = self._translate_fieldnames(fields)
return super(TranslationQueryset, self).values(*fields)
def values_list(self, *fields, **kwargs):
fields = self._translate_fieldnames(fields)
return super(TranslationQueryset, self).values_list(*fields, **kwargs)
def dates(self, field_name, kind=None, order='ASC'):
if django.VERSION < (1, 8):
field_name = self.field_translator(field_name)
return super(TranslationQueryset, self).dates(field_name, kind=kind, order=order)
def datetimes(self, field, *args, **kwargs):
if django.VERSION < (1, 8):
field = self.field_translator(field)
return super(TranslationQueryset, self).datetimes(field, *args, **kwargs)
def select_related(self, *fields):
if not fields:
raise NotImplementedError('To use select_related on a translated model, '
'you must provide a list of fields.')
if fields == (None,):
self._raw_select_related = []
else:
self._raw_select_related.extend(fields)
return self
def complex_filter(self, filter_obj):
# Don't know how to handle Q object yet, but it is probably doable...
# An unknown type object that supports 'add_to_query' is a different story :)
if isinstance(filter_obj, models.Q) or hasattr(filter_obj, 'add_to_query'):
raise NotImplementedError()
newargs, newkwargs = self._translate_args_kwargs(**filter_obj)
return super(TranslationQueryset, self)._filter_or_exclude(None, *newargs, **newkwargs)
def annotate(self, *args, **kwargs):
newkwargs = dict((k, self._translate_expression(v)) for k, v in kwargs.items())
for arg in args:
arg = self._translate_expression(arg)
try:
alias = arg.default_alias
except (AttributeError, TypeError):
raise TypeError("Complex annotations require an alias")
if alias.startswith('master__'):
alias = alias[8:]
if alias in kwargs:
raise ValueError("The named annotation '%s' conflicts with the "
"default name for another annotation." % alias)
newkwargs[alias] = arg
qs = super(TranslationQueryset, self).annotate(**newkwargs)
switch_fields = set(qs._hvad_switch_fields)
switch_fields.update(newkwargs)
qs._hvad_switch_fields = tuple(switch_fields)
return qs
def order_by(self, *field_names):
"""
Returns a new QuerySet instance with the ordering changed.
"""
fieldnames = self._translate_fieldnames(field_names)
return super(TranslationQueryset, self).order_by(*fieldnames)
def reverse(self):
return super(TranslationQueryset, self).reverse()
def defer(self, *field_names):
if field_names == (None,):
fieldnames = field_names
else:
fieldnames = self._translate_fieldnames(field_names)
return super(TranslationQueryset, self).defer(*fieldnames)
def only(self, *field_names):
fieldnames = self._translate_fieldnames(field_names)
fieldnames += ('master__%s' % self.shared_model._meta.pk.name, 'master_id', 'language_code')
return super(TranslationQueryset, self).only(*fieldnames)
#===============================================================================
# Fallbacks
#===============================================================================
class _SharedFallbackQueryset(QuerySet):
translation_fallbacks = None
def use_fallbacks(self, *fallbacks):
if django.VERSION >= (1, 9):
raise AssertionError(
'TranslationManager.untranslated().use_fallbacks() is not supported on Django 1.9, '
'and is deprecated on previous versions as well. Please use the fallbacks() method '
'on queryset instead, eg: MyModel.objects.language().fallbacks()')
warnings.warn('TranslationManager.untranslated().use_fallbacks() is deprecated. '
'Please use the fallbacks() method on queryset instead, eg: '
'MyModel.objects.language().fallbacks()', DeprecationWarning, stacklevel=2)
self.translation_fallbacks = fallbacks or (None,)+FALLBACK_LANGUAGES
return self
def _clone(self, klass=None, setup=False, **kwargs):
kwargs.update({
'translation_fallbacks': self.translation_fallbacks,
})
if django.VERSION < (1, 9):
kwargs.update({'klass': klass, 'setup': setup})
return super(_SharedFallbackQueryset, self)._clone(**kwargs)
def aggregate(self, *args, **kwargs):
raise NotImplementedError()
def annotate(self, *args, **kwargs):
raise NotImplementedError()
def defer(self, *args, **kwargs):
raise NotImplementedError()
def only(self, *args, **kwargs):
raise NotImplementedError()
class LegacyFallbackQueryset(_SharedFallbackQueryset): #pragma: no cover
'''
Queryset that tries to load a translated version using fallbacks on a per
instance basis.
BEWARE: creates a lot of queries!
'''
def _get_real_instances(self, base_results):
"""
The logic for this method was taken from django-polymorphic by Bert
Constantin (https://github.com/bconstantin/django_polymorphic) and was
slightly altered to fit the needs of django-hvad.
"""
# get the primary keys of the shared model results
base_ids = [obj.pk for obj in base_results]
fallbacks = [get_language() if lang is None else lang
for lang in self.translation_fallbacks]
# get all translations for the fallbacks chosen for those shared models,
# note that this query is *BIG* and might return a lot of data, but it's
# arguably faster than running one query for each result or even worse
# one query per result per language until we find something
translations_manager = self.model._meta.translations_model.objects
baseqs = translations_manager.select_related('master')
translations = baseqs.filter(language_code__in=fallbacks,
master__pk__in=base_ids)
fallback_objects = defaultdict(dict)
# turn the results into a dict of dicts with shared model primary key as
# keys for the first dict and language codes for the second dict
for obj in translations:
fallback_objects[obj.master.pk][obj.language_code] = obj
# iterate over the share dmodel results
for instance in base_results:
translation = None
# find the translation
for fallback in fallbacks:
translation = fallback_objects[instance.pk].get(fallback, None)
if translation is not None:
break
# if we found a translation, yield the combined result
if translation:
yield combine(translation, self.model)
else:
# otherwise yield the shared instance only
_logger.error("no translation for %s.%s (pk=%s)" %
(instance._meta.app_label,
instance.__class__.__name__,
str(instance.pk)))
yield instance
def iterator(self):
"""
The logic for this method was taken from django-polymorphic by Bert
Constantin (https://github.com/bconstantin/django_polymorphic) and was
slightly altered to fit the needs of django-hvad.
"""
base_iter = super(LegacyFallbackQueryset, self).iterator()
# only do special stuff when we actually want fallbacks
if self.translation_fallbacks:
while True:
base_result_objects = []
reached_end = False
# get the next "chunk" of results
for i in range(CHUNK_SIZE):
try:
instance = next(base_iter)
base_result_objects.append(instance)
except StopIteration:
reached_end = True
break
# "combine" the results with their fallbacks
real_results = self._get_real_instances(base_result_objects)
# yield em!
for instance in real_results:
yield instance
# get out of the while loop if we're at the end, since this is
# an iterator, we need to raise StopIteration, not "return".
if reached_end:
raise StopIteration
else:
# just iterate over it
for instance in base_iter:
yield instance
class SelfJoinFallbackQueryset(_SharedFallbackQueryset):
def iterator(self):
# only do special stuff when we actually want fallbacks
if self.translation_fallbacks:
fallbacks = [get_language() if lang is None else lang
for lang in self.translation_fallbacks]
tmodel = self.model._meta.translations_model
taccessor = self.model._meta.translations_accessor
taccessorcache = (
getattr(self.model, taccessor).rel.get_cache_name() if django.VERSION >= (1, 9) else
getattr(self.model, taccessor).related.get_cache_name()
)
tcache = self.model._meta.translations_cache
masteratt = tmodel._meta.get_field('master').attname
field = BetterTranslationsField(fallbacks, master=masteratt)
qs = self._clone()
qs.query.add_select_related((taccessor,))
# This join will be reused by the select_related. We must provide it
# anyway because the order matters and add_select_related does not
# populate joins right away.
if django.VERSION >= (1, 8):
alias1 = qs.query.join(Join(
tmodel._meta.db_table,
qs.query.get_initial_alias(),
None,
LOUTER,
getattr(qs.model, taccessor).field.rel if django.VERSION >= (1, 9) else
getattr(qs.model, taccessor).related.field.rel,
True
))
alias2 = qs.query.join(Join(
tmodel._meta.db_table,
alias1,
None,
LOUTER,
field,
True
))
else:
nullable = {'nullable': True}
alias1 = qs.query.join((qs.query.get_initial_alias(), tmodel._meta.db_table,
((qs.model._meta.pk.attname, masteratt),)),
join_field=getattr(qs.model, taccessor).related.field.rel,
**nullable)
alias2 = qs.query.join((tmodel._meta.db_table, tmodel._meta.db_table,
((masteratt, masteratt),)),
join_field=field, **nullable)
add_alias_constraints(qs, (tmodel, alias2), id__isnull=True)
# We must force the _unique field so get_cached_row populates the cache
# Unfortunately, this means we must load everything in one go
related_field = (getattr(qs.model, taccessor).field if django.VERSION >= (1, 9) else
getattr(qs.model, taccessor).related.field)
with ForcedUniqueFields([related_field]):
objects = []
for instance in super(SelfJoinFallbackQueryset, qs).iterator():
try:
translation = getattr(instance, taccessorcache)
except AttributeError: #pragma: no cover
_logger.error("no translation for %s.%s (pk=%s)",
instance._meta.app_label,
instance.__class__.__name__,
str(instance.pk))
else:
setattr(instance, tcache, translation)