django-modeltranslation/modeltranslation/manager.py

356 lines
14 KiB
Python

# -*- coding: utf-8 -*-
"""
The idea of MultilingualManager is taken from
django-linguo by Zach Mathew
https://github.com/zmathew/django-linguo
"""
from django.db import models
from django.db.models import FieldDoesNotExist
from django.db.models.fields.related import RelatedField, RelatedObject
from django.db.models.sql.where import Constraint
from django.utils.tree import Node
try:
from django.db.models.lookups import Lookup
from django.db.models.sql.datastructures import Col
NEW_LOOKUPS = True
except ImportError:
NEW_LOOKUPS = False
from modeltranslation import settings
from modeltranslation.fields import TranslationField
from modeltranslation.utils import (build_localized_fieldname, get_language,
auto_populate)
def get_translatable_fields_for_model(model):
from modeltranslation.translator import NotRegistered, translator
try:
return translator.get_options_for_model(model).get_field_names()
except NotRegistered:
return None
def rewrite_lookup_key(model, lookup_key):
pieces = lookup_key.split('__', 1)
original_key = pieces[0]
translatable_fields = get_translatable_fields_for_model(model)
if translatable_fields is not None:
# If we are doing a lookup on a translatable field,
# we want to rewrite it to the actual field name
# For example, we want to rewrite "name__startswith" to "name_fr__startswith"
if pieces[0] in translatable_fields:
pieces[0] = build_localized_fieldname(pieces[0], get_language())
if len(pieces) > 1:
# Check if we are doing a lookup to a related trans model
fields_to_trans_models = get_fields_to_translatable_models(model)
for field_to_trans, transmodel in fields_to_trans_models:
# Check ``original key``, as pieces[0] may have been already rewritten.
if original_key == field_to_trans:
pieces[1] = rewrite_lookup_key(transmodel, pieces[1])
break
return '__'.join(pieces)
def rewrite_order_lookup_key(model, lookup_key):
if lookup_key.startswith('-'):
return '-' + rewrite_lookup_key(model, lookup_key[1:])
else:
return rewrite_lookup_key(model, lookup_key)
_F2TM_CACHE = {}
def get_fields_to_translatable_models(model):
if model not in _F2TM_CACHE:
results = []
for field_name in model._meta.get_all_field_names():
field_object, modelclass, direct, m2m = model._meta.get_field_by_name(field_name)
# Direct relationship
if direct and isinstance(field_object, RelatedField):
if get_translatable_fields_for_model(field_object.related.parent_model) is not None:
results.append((field_name, field_object.related.parent_model))
# Reverse relationship
if isinstance(field_object, RelatedObject):
if get_translatable_fields_for_model(field_object.model) is not None:
results.append((field_name, field_object.model))
_F2TM_CACHE[model] = results
return _F2TM_CACHE[model]
_C2F_CACHE = {}
def get_field_by_colum_name(model, col):
# First, try field with the column name
try:
field = model._meta.get_field(col)
if field.column == col:
return field
except FieldDoesNotExist:
pass
field = _C2F_CACHE.get((model, col), None)
if field:
return field
# D'oh, need to search through all of them.
for field in model._meta.fields:
if field.column == col:
_C2F_CACHE[(model, col)] = field
return field
assert False, "No field found for column %s" % col
class MultilingualQuerySet(models.query.QuerySet):
def __init__(self, *args, **kwargs):
super(MultilingualQuerySet, self).__init__(*args, **kwargs)
self._post_init()
def _post_init(self):
self._rewrite = True
self._populate = None
if self.model and (not self.query.order_by):
if self.model._meta.ordering:
# If we have default ordering specified on the model, set it now so that
# it can be rewritten. Otherwise sql.compiler will grab it directly from _meta
ordering = []
for key in self.model._meta.ordering:
ordering.append(rewrite_order_lookup_key(self.model, key))
self.query.add_ordering(*ordering)
# This method was not present in django-linguo
def _clone(self, klass=None, *args, **kwargs):
if klass is not None and not issubclass(klass, MultilingualQuerySet):
class NewClass(klass, MultilingualQuerySet):
pass
NewClass.__name__ = 'Multilingual%s' % klass.__name__
klass = NewClass
kwargs.setdefault('_rewrite', self._rewrite)
kwargs.setdefault('_populate', self._populate)
return super(MultilingualQuerySet, self)._clone(klass, *args, **kwargs)
# This method was not present in django-linguo
def rewrite(self, mode=True):
return self._clone(_rewrite=mode)
# This method was not present in django-linguo
def populate(self, mode='all'):
"""
Overrides the translation fields population mode for this query set.
"""
return self._clone(_populate=mode)
def _rewrite_applied_operations(self):
"""
Rewrite fields in already applied filters/ordering.
Useful when converting any QuerySet into MultilingualQuerySet.
"""
self._rewrite_where(self.query.where)
self._rewrite_where(self.query.having)
self._rewrite_order()
# This method was not present in django-linguo
def _rewrite_col(self, col):
"""Django 1.7 column name rewriting"""
if isinstance(col, Col):
new_name = rewrite_lookup_key(self.model, col.target.name)
if col.target.name != new_name:
new_field = self.model._meta.get_field(new_name)
if col.target is col.source:
col.source = new_field
col.target = new_field
elif hasattr(col, 'col'):
self._rewrite_col(col.col)
elif hasattr(col, 'lhs'):
self._rewrite_col(col.lhs)
def _rewrite_where(self, q):
"""
Rewrite field names inside WHERE tree.
"""
if not NEW_LOOKUPS and isinstance(q, tuple) and isinstance(q[0], Constraint):
c = q[0]
if c.field is None:
c.field = get_field_by_colum_name(self.model, c.col)
new_name = rewrite_lookup_key(self.model, c.field.name)
if c.field.name != new_name:
c.field = self.model._meta.get_field(new_name)
c.col = c.field.column
elif NEW_LOOKUPS and isinstance(q, Lookup):
self._rewrite_col(q.lhs)
if isinstance(q, Node):
for child in q.children:
self._rewrite_where(child)
def _rewrite_order(self):
self.query.order_by = [rewrite_order_lookup_key(self.model, field_name)
for field_name in self.query.order_by]
# This method was not present in django-linguo
def _rewrite_q(self, q):
"""Rewrite field names inside Q call."""
if isinstance(q, tuple) and len(q) == 2:
return rewrite_lookup_key(self.model, q[0]), q[1]
if isinstance(q, Node):
q.children = list(map(self._rewrite_q, q.children))
return q
# This method was not present in django-linguo
def _rewrite_f(self, q):
"""
Rewrite field names inside F call.
"""
if isinstance(q, models.F):
q.name = rewrite_lookup_key(self.model, q.name)
return q
if isinstance(q, Node):
q.children = list(map(self._rewrite_f, q.children))
return q
def _filter_or_exclude(self, negate, *args, **kwargs):
if not self._rewrite:
return super(MultilingualQuerySet, self)._filter_or_exclude(negate, *args, **kwargs)
args = map(self._rewrite_q, args)
for key, val in kwargs.items():
new_key = rewrite_lookup_key(self.model, key)
del kwargs[key]
kwargs[new_key] = self._rewrite_f(val)
return super(MultilingualQuerySet, self)._filter_or_exclude(negate, *args, **kwargs)
def _get_original_fields(self):
return [f.attname for f in self.model._meta.fields if not isinstance(f, TranslationField)]
def order_by(self, *field_names):
"""
Change translatable field names in an ``order_by`` argument
to translation fields for the current language.
"""
if not self._rewrite:
return super(MultilingualQuerySet, self).order_by(*field_names)
new_args = []
for key in field_names:
new_args.append(rewrite_order_lookup_key(self.model, key))
return super(MultilingualQuerySet, self).order_by(*new_args)
def update(self, **kwargs):
if not self._rewrite:
return super(MultilingualQuerySet, self).update(**kwargs)
for key, val in kwargs.items():
new_key = rewrite_lookup_key(self.model, key)
del kwargs[key]
kwargs[new_key] = self._rewrite_f(val)
return super(MultilingualQuerySet, self).update(**kwargs)
update.alters_data = True
# This method was not present in django-linguo
@property
def _populate_mode(self):
# Populate can be set using a global setting or a manager method.
if self._populate is None:
return settings.AUTO_POPULATE
return self._populate
# This method was not present in django-linguo
def create(self, **kwargs):
"""
Allows to override population mode with a ``populate`` method.
"""
with auto_populate(self._populate_mode):
return super(MultilingualQuerySet, self).create(**kwargs)
# This method was not present in django-linguo
def get_or_create(self, **kwargs):
"""
Allows to override population mode with a ``populate`` method.
"""
with auto_populate(self._populate_mode):
return super(MultilingualQuerySet, self).get_or_create(**kwargs)
def _append_translated(self, fields):
"If translated field is encountered, add also all its translation fields."
fields = set(fields)
from modeltranslation.translator import translator
opts = translator.get_options_for_model(self.model)
for key, translated in opts.fields.items():
if key in fields:
fields = fields.union(f.name for f in translated)
return fields
# This method was not present in django-linguo
def defer(self, *fields):
fields = self._append_translated(fields)
return super(MultilingualQuerySet, self).defer(*fields)
# This method was not present in django-linguo
def only(self, *fields):
fields = self._append_translated(fields)
return super(MultilingualQuerySet, self).only(*fields)
# This method was not present in django-linguo
def raw_values(self, *fields):
return super(MultilingualQuerySet, self).values(*fields)
# This method was not present in django-linguo
def values(self, *fields):
if not self._rewrite:
return super(MultilingualQuerySet, self).values(*fields)
if not fields:
# Emulate original queryset behaviour: get all fields that are not translation fields
fields = self._get_original_fields()
new_args = []
for key in fields:
new_args.append(rewrite_lookup_key(self.model, key))
vqs = super(MultilingualQuerySet, self).values(*new_args)
vqs.field_names = list(fields)
return vqs
# This method was not present in django-linguo
def values_list(self, *fields, **kwargs):
if not self._rewrite:
return super(MultilingualQuerySet, self).values_list(*fields, **kwargs)
if not fields:
# Emulate original queryset behaviour: get all fields that are not translation fields
fields = self._get_original_fields()
new_args = []
for key in fields:
new_args.append(rewrite_lookup_key(self.model, key))
return super(MultilingualQuerySet, self).values_list(*new_args, **kwargs)
# This method was not present in django-linguo
def dates(self, field_name, *args, **kwargs):
if not self._rewrite:
return super(MultilingualQuerySet, self).dates(field_name, *args, **kwargs)
new_key = rewrite_lookup_key(self.model, field_name)
return super(MultilingualQuerySet, self).dates(new_key, *args, **kwargs)
class MultilingualManager(models.Manager):
use_for_related_fields = True
def rewrite(self, *args, **kwargs):
return self.get_queryset().rewrite(*args, **kwargs)
def populate(self, *args, **kwargs):
return self.get_queryset().populate(*args, **kwargs)
def raw_values(self, *args, **kwargs):
return self.get_queryset().raw_values(*args, **kwargs)
def get_queryset(self):
if hasattr(super(MultilingualManager, self), 'get_queryset'):
qs = super(MultilingualManager, self).get_queryset()
else: # Django 1.4 / 1.5 compat
qs = super(MultilingualManager, self).get_query_set()
if qs.__class__ == models.query.QuerySet:
qs.__class__ = MultilingualQuerySet
else:
class NewClass(qs.__class__, MultilingualQuerySet):
pass
NewClass.__name__ = 'Multilingual%s' % qs.__class__.__name__
qs.__class__ = NewClass
qs._post_init()
qs._rewrite_applied_operations()
return qs
get_query_set = get_queryset